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Common gardening terms explained
Whether you’re new to gardening or simply want to brush up on your garden vocabulary, read along to learn what the most common gardening terms mean.
Abscission: Natural dropping of leaves, flowers and other plant parts.
Acidic: A soil, compost, or liquid with a pH between 0 and 7.0 (on a scale of 0.0-14.0). Often referred to as “sour” soil by gardeners.
Acre: A measure of land totaling 43,560 square feet. A square acre is 208.75 feet on each side.
Action or damage threshold: The level of a pest population at which control is initiated.
Aeration: Any method of loosening soil or compost to allow air to circulate.
Aerobic: Describes organisms living or occurring only when oxygen is present.
Alkaline: A soil with a pH between 7.0 and 14 (on a scale of 0.0-14.0). Often referred to as “sweet” soil by gardeners.
Alpine: Term used to describe small plants suitable for growing in rock gardens.
Alternate Bearing: The tendency of many fruit and nut trees to alternate large crops one year followed by a small, or nonexistent, crop the next year.
Alternate leaves: Arrangement of leaves on the stem, placed singly at different heights on the stem or axis. Any arrangement that is not opposite or whorled.
Anaerobic: Describes organisms living or occurring where there is no oxygen.
Annual: A plant that grows, flowers, produces seed all in one season, and then does not survive the winter. It must be planted each year. Many plants we call annual may be perennial in warmer locations.
Antagonists: Organisms that release toxins or otherwise change conditions so that activity or growth of the pest organism is reduced.
Anther: The terminal part of a stamen, which contains pollen.
Aquatic: A plant that grows in water, either submerged or with its flowers and leaves floating on the surface.
Arboretum: A garden with a large collection of trees and shrubs cultivated for scientific or educational purposes.
Auricle: An identifying feature on grasses. An appendage near the lower part of the leaf blade. May be absent or clasping.
Axil: The location on a stem between the upper surface of a leaf or leafstalk and the stem from which it is growing.
Axilary buds: Buds that form in leaf axils.
Azotobacter: Type of bacteria found in compost piles that can fix atmospheric nitrogen into a form plants can use.
Bacteria: Single celled organisms that require a host plant or some other organic material as a food source.
Balled and Burlapped (B&B): Generally larger trees or shrubs that were grown in the ground at a nursery. When ready for sale they are dug, wrapped in burlap and then sold. Some plants may be placed in wire baskets in addition to being wrapped in burlap.
Bare Root: Plants, usually trees and shrubs, that are sold with little to no soil around the roots. Some perennials are also sold as bare root plants. This is most common with mail ordered plants.
Bed Planting: Growing vegetables in closely spaced rows that grow together at crop maturity.
Bedding Plants: Generally annual or tender plants used in quantity for a temporary garden display in summer and fall/winter.
Beneficial Insects: Insects that benefits your garden by eating or laying its eggs in other insects, thereby controlling their population.
Biennial: A plant that completes its full life-cycle in two growing seasons. It produces leaves in the first and flowers in the second.
Biodegradable: Able to decompose or break down through natural bacterial or fungal action. Substances made of organic matter are biodegradable.
Biological Control Agents: See Natural Enemies.
Biological Pest Control: Using living organisms such as beneficial insects or parasites to destroy garden pests.
Biopesticide: A pest control product which is derived from natural materials such as animals, plants, bacteria and minerals.
Bokashi: A type of composting method. Bokashi means “fermented organic matter” in Japanese. As opposed to a classic compost recipe involving browns, greens, oxygen, and time, the Bokashi method rapidly ferments food waste in an air-tight container with the aid of a specialized inoculant.
Bolting: Vegetables which quickly go to flower rather than producing the food crop.; usually caused by late planting and too warm temperatures.
Bone Meal: Finely ground white or light gray bone; adds nitrogen and phosphorous to the soil over time as a slow release fertilizer and encourages root growth.
Broadleaf Weeds: General classification of weeds that have 2 cotyledons; leaves are generally broad and vary in size and shape.
Bulb: An underground storage organ with fleshy scale leaves from which the plant flowers and grows before becoming dormant. Example: Tulips, Daffodils.
Calcareous: A soil containing calcium carbonate in the mineral form; these soils have a high pH and are very well buffered against changes in soil pH.
Calcitic Limestone: A common material used for “liming” soil that has an acid level that is too high. This type is most commonly used and contains calcium carbonate.
Calyx: The sepals of a flower; the outermost series of flower parts; it is usually, but not always, green and leaf-like in texture.
Cambium: A thin ring of tissue within the stem, branch, and trunk that continually forms nutrient and water-conducting vessels.
Catkin: Slender, spike-like, drooping flower cluster.
CEC: Cation Exchange Capacity, is a measure of how much fertilizer your soil can hold and release over time. A high CEC is good because it means your soil will hold a lot of fertilizer. Clay soils have high CEC. A low CEC means you will have to fertilize more often. Sandy soils have low CEC.
Chelation: The formation of bonds between organic compounds and metals, some of which are insoluble, as in humus. Soluble chelates are used in fertilizers to help keep nutrient metals, such as iron, mobile in the soil and thus available to plants rather than locked up in insoluble mineral salts.
Chlorophyll: The green pigment that is responsible for absorption of light, necessary for photosynthesis.
Chlorosis: A yellowing or blanching of the leaves due to lack of chlorophyll, nutrient deficiencies or disease.
Clay: A constituent of soils that consists of particles less than 0.002 mm in size.
Clump Forming: Plants that form clumps of foliage, often spreading to form other clumps close by.
Cold Frame: An unheated structure covered with glass or plastic placed on the ground or in a garden bed that has a clear top. By design, it increases temperatures over the ambient temperature and is used for growing seedlings for transplant or for food crops, extending the harvest season.
Cold Sensitive: A plant or tissue that is damaged or dies due to prolonged exposure to low temperatures.
Collar: The junction between leaf blade and leaf sheath in grass and sedge leaves.
Compaction: Soil condition that results from tightly packing soil; compacted soil allows for only marginal aeration and root penetration.
Companion Planting: The sowing of seeds or planting in the garden in such a way that plants help each other grow instead of competing against each other or to discourage insect infestation.
Complete fertilizer: Fertilizer containing nitrogen, phosphorus, and potassium, the three nutrients in which plants are most commonly deficient.
Compost: Completely decayed organic matter used for conditioning soil. It is dark, odorless and rich in nutrients.
Compost Tea: A form of natural liquid fertilizer that is made by ‘brewing’ or steeping finished compost (described above) or worm castings in water. The result is a mild but nutrient-rich solution used to water and feed plants. Compost tea may be passively steeped, or actively aerated (bubbled) to increase microbial activity.
Conidia: Asexual spores.
Conifer: Woody trees and shrubs that produce cones; common conifers include pines, firs, spruce, juniper, redwood and hemlocks.
Controlled Release Fertilizer: Also called Time Release Fertilizer. Fertilizer comes in pellets and is an improved version of Slow Release Fertilizer. Fertilizer is released based on soil temperature itself (not microbe action) and tends to be more exact than Slow Release Fertilizer.
Cordon: A plant carefully trained to grow as one main stem, or occasionally two or three main stems, by removing side-shoots. E.g tomato plants.
Corm: Short, solid, enlarged, underground stem from which roots grow. Corms are food-storage organs. They contain one bud that will produce a new plant.
Corona: A crown like structure on some corollas, as in daffodils and the milkweed family.
Cotyledon: Energy storage components of a seed that feed the plant before the emergence of its first true leaves.
Cover Crop: Vegetation grown to protect and build the soil during an interval when the area would otherwise lie fallow.
Cool Season Crops: Cold hardy or frost-tolerant vegetable crops that prefer cooler soil and air temperatures to thrive. Includes the brassica family (cabbage, broccoli, cauliflower), leafy greens, and root vegetables (radishes, carrots, beets, turnips).
Crop Rotation: The planting of a specific crop in a site different from the previous year.
Cross-Pollination: When two or more plants of the same species pollinate each others’ flowers; for many fruit trees, cross-pollination is necessary to produce a crop.
Crown: The growing point of a plant from which new shoots emerge, at or just below the soil surface. E.g. Asparagus.
A species that was selected or bred by humans for a particular feature. Cultivars carry a specific name in addition to the scientific name and/or common name, e.g. ‘Annabelle’.
Cuticle: A continuous layer waxy substances covering over the outer surfaces of the epidermis of plants, it contains cutin and protects against water loss/water gain and other damage.
Cutting: A vegetative method of plant propagation whereby a piece of plant leaf, stem, root or bud is cut from a parent plant. It is then inserted into a growing medium to form roots, thus developing a new plant.
Damping Off: Decay of young seedlings at ground level following fungal attack. Often the result of soil borne diseases and over watering.
Dappled Shade: Areas where there is a mixture of sun and shade, generally because a deciduous tree is nearby. Dappled shade is similar to partial shade.
Day-Neutral: Plants whose flowering is not dictated by day-length, which includes tomatoes, corn, and cucumbers; some crops that are not naturally day-neutral, such as strawberries, have been bred that way in an effort to extend the harvest season
Days to emerge: Number of days, on average, that it will take a seedling to emerge from the soil or medium in favorable conditions.
Days to harvest: Number of days from sowing (or transplant) to harvest.
Dead Heading: The act of removing spent flowers or flowerheads for aesthetics, to prolong bloom for up to several weeks or promote re-bloom, or to prevent seeding.
Deciduous: Trees or shrubs that lose their leaves in fall and winter.
Deep Shade: A plant requiring less than 2 hours of dappled sun a day.
Deer Resistant Plants: Plants that deer are less likely to nibble on. Hungry deer (or rabbits, ground hogs, squirrels etc.) will, however, eat almost anything if they are hungry or thirsty. Deer tastes also vary by region so trial and error may be necessary to choose deer resistant plants for your area.
Defoliate: Foliage loss due to biotic or abiotic factors (e.g. insect feeding, chemical application).
Denitrification: The conversion of nitrates into atmospheric nitrogen by soil microbes in water logged soils.
Dehydration or loss of water. Insecticidal soap desiccates its victims.
Determinate: Describes tomatoes that stop growing when fruit begins forming from the topmost flower bud, making them more compact at around 3’–4′. Most of the crop ripens within a couple weeks time, making these a great choice for canning.
Direct Seed: To seed directly into the soil instead of starting your seeds indoors.
Disease Resistance: Exhibiting less susceptibility or an immunity against specific diseases as compared to other varieties.
Disease Tolerance: Better ability to thrive with the stress of infection as compared to other varieties.
Dolomitic Limestone: Lime that supplies both calcium and magnesium.
Dormant: Plants which are in a (yearly) resting state, most often during low or high temperatures.
Double Digging: A method of preparing the soil by digging a trench then putting the soil from one row into the next row.
Drainage: The ability for water to pass freely through the soil; without good drainage, which can be achieved by building raised beds or adding soil amendments, the planting area becomes waterlogged.
Drip irrigation: Any type of irrigation in which the water drips out slowly at the base of individual plants; this approach uses far less water than sprinklers.
Drought Resistant: Plants that can withstand periods with little to no supplemental water when planted and established in the landscape. No plant in a pot is truly drought resistant as they all need some water. All plants will need to be watered while getting established. Annuals and perennials need 2 to 3 weeks to establish, shrubs and trees need a year to become established. Often used interchangeably with drought tolerant although their definitions are different.
Drought Tolerant: Ability to survive or thrive in low water conditions. Also known as “water-wise.” Plants that deal with severe drought on a regular basis, and recover from repeated wilting. All plants will need to be watered while getting established. Annuals and perennials need 2 to 3 weeks to establish, shrubs and trees need a year to become established. Often used interchangeably with drought resistant although their definitions are different.
Dwarf: Plant that has been bred to be smaller than is typical for the species; fruit trees are often classified according to their degree of dwarfness.
Earth-Up: To draw soil up around a plant to exclude light, protect from frost or encourage roots to develop from the stem. This is commonly done with potato crops.
EC: (Electric Conductivity) A measure of how much salt is in your soil. High EC can mean that you have a problem from salt water or snow removal. Soils with very high EC can burn plants. A low EC means you need to fertilize (fertilizer is essentially make up of different types of salt). The salts that make up fertilizer are good for your plants (although too much can be bad). The salt from the ocean or snow removal is bad for plants.
Edging: Line that creates visual interest and separation, for example, between the lawn and an annual border.
Emergence: The time at which the seedling first appears above the ground.
Epidermis: The outer layer of plant tissue.
Ericaceous: Used to describe plants that like acid soil and will not tolerate alkaline soils (containing lime or chalk). E.g Blueberries.
Espalier: A plant pruning and training technique that creates a wide, flat structure. Commonly used for fruit trees. Great for small spaces and against structures, fences or walls for a unique visual impact.
Etiolation: Characterized by lanky, weak, pale plant growth, resulting from low or no-light conditions.
Evaporative cooling: Removal of heat from the plant through evapotranspiration (evaporation of water released through the plant stomata).
Everbearing: Refers to strawberry and raspberry varieties that yield a small crop in early summer, a few berries throughout the rest of the summer, and another heavier crop during late summer and early autumn.
Evergreen: A plant that retains all or most of it’s foliage throughout the year.
Exposure – the optimum amount of sun or shade each plant needs to thrive
- Full Sun – 6 or more hours of direct sun a day
- Partial Sun or Partial Shade – 4 to 6 hours of direct sun a day
- Full Shade – less than 4 hours of direct sun a day
- Dappled Shade – areas where there is a mixture of sun and shade, generally because a deciduous tree is nearby. Dappled shade is similar to partial shade.
Family: In the taxonomic classification of organisms, this is the rank above genus and below order (family names are written in Latin and always end in –ceae); similar types of plants are often referred by their family name, such as brassicas (Brassicaceae), nightshades (Solanaceae) and roses (Rosaceae).
Fertilizer: An organic or synthetic material added to the soil or the plant, that is important for its nutrient value.
Filler – Plants that fill in the middle area of a container connecting the spillers and fillers and making the container look full.
Fish Meal: Ground up fish. Contains nitrogen and phosphorus.
Floricane: Refers to raspberry and blackberry stems that grow for one year before bearing fruit and flowers e.g. summer-fruiting raspberries and blackberries.
Foliar Fertilizing: A technique of feeding plants by applying (spraying) liquid fertilizer directly to plant leaves.
Freeze Tolerant: (A plant that) can survive prolonged exposure to freezing temperatures.
Friable: An easily worked soil.
Frost(-Free) Date: Average date in spring (Last Frost date) when your area no longer experiences frost and the average date in fall for when your area experiences the first frost (First Frost Date). This date is important for knowing when to plant in spring. Knowing both spring and fall frost dates will help you determine the length of your growing season.
A low-lying area where frost occurs late in the season.
Frost Sensitive: Plants that are not frost tolerant and will die as a result of exposure to freezing temperatures.
Frost Tolerant: Plant that tolerate some cool weather and even frost, although the amount of tolerance varies between crops and even varieties.
Fruit: A seed capsule that emerges from a flower, such as a tomato or melon.
Full Shade: less than 4 hours of direct sun a day.
Full Sun: 6 or more hours of direct sun a day.
Fungi: Multi-celled organisms that reproduce by spores and rely on living or dead organic matter for food.
Fungicides: Compounds used to prevent the spread of fungi in gardens and crops, which can cause serious damage to plants.
Furrow: A small trench made in the soil for planting seeds; may also refer to the depression between raised planting beds
Gall: Abnormal growth of a plant caused by the presence in its tissues of a young insect or some other organism (fungi, bacteria etc.; aphids, gall wasps, and gall midges are among the major gall-causing insects.
Generation: The group of individuals of a given species that have been reproduced at approximately the same time; the group of individuals of the same genealogical rank.
Genus: In the taxonomic classification of organisms, this is the rank above species and below family (plural: genera); it is synonymous with the “scientific” or “Latin” name of plants (i.e. Rosa, Salvia and Quercus) and is always capitalized
Germinate: The beginning of growth in seeds, the action of sprouting, budding or shooting, above the soil. This occurs whenever a plant or seed begins to vegetate into leafy young plants. The breaking of dormancy in seeds or the sprouting of pollen grains deposited on a stigma.
Girdle: Encircling of plant roots, stems, trunks or branches resulting in a constriction of the plant part, or a reduction of water and nutrient flow through the girdled plant part; most often the stem of a woody plants that has been tied to tightly to a stake or support.
GMO: (Genetically Modified Organism). Commonly means genetically engineered, indicating that the variety was manipulated at the gene level in a laboratory.
Grasses: A category of plants that are monocots, have narrow leaves and a growing point at our just below the soil surface.
Grafting: A horticulture technique when a cut portion of a plant is joined or fused to another – to grow together as one plant. A common practice where a strong, disease-resistant, or otherwise ideal lower portion (the rootstock) is fused with various upper portions (the scion).
Green Manure: A crop that is grown and then incorporated into the soil to increase soil fertility or organic matter content. Usually turned over into the soil a few weeks before new planting begins.
Greensand: A soil amendment that is mined from the ocean floor; it is a natural, organic source of potassium and numerous micronutrients.
Ground Cover: Group of plants usually used to cover bare earth and create a uniform appearance.
Guano: Organic fertilizer made from the excrement of seabirds and bats; available in both high-nitrogen and high-phosphorus forms, guano is mined from dried deposits found beneath historic nesting areas in some parts of the world.
Gynoecious: A plant with only pollen-accepting flowers. A pollinator plant with pollen-producing flowers is required for fruit production. These varieties are generally very productive and fast to mature.
Habit : The general structure of the plant.
Climbing – Plants that climb fences or other structures by using roots or stem structures to grip, vines are climbers.
Clump Forming – Plant that forms clumps of foliage, often spreading to form other clumps close by.
Mounded – Plants with a rounded appearance, they are usually wider than they are tall.
Spreading – Plants that grow low and spread along the ground, rooting at nodes along the stem.
Trailing – Plants that trail along the ground or out of pots but do not root at nodes along the stem.
Upright – A plant that is taller than it is wide with straight (more or less) edges, these plants often have a somewhat spikey appearance.
Hardening Off: The process of acclimatizing plants grown under protection, in the greenhouse for example, to cooler conditions outdoors.
Hardiness Zone: Temperature zones are based on the lowest average temperature each area is expected to receive during the winter. Hardiness zones are used to determine whether a plant is likely to survive in an area.
Hardpan: Impervious layer of soil or clay lying beneath the topsoil.
Heat Sensitive: Plant/tissue damage or death due to exposure to temperatures above an upper limit.
Heat Tolerant: Plants that flourish despite hot temperatures.
Heavy Soil: A soil that contains a high proportion of clay and is poorly drained.
Heirloom: Open-pollinated varieties over 50 years old.
Herbaceous: Plants that do not have woody stems, only soft green stalks, and leaves.
Herbicide: A substance that kills plants or inhibits plant growth.
Hill Plantings: Planting multiple seeds together in clumps.
Holistic: A system designed to optimize the productivity and fitness of diverse, interdependent, communities within the agro-ecosystem.
Honeydew: The sweet liquid released from the anus of aphids and some other sap sucking bugs.
Horticulture: The art and science of plant cultivation.
Humus: A fairly stable, complex group of nutrient-storing molecules created by microbes and other forces of decomposition by the conversion of organic matter.
Hybrid: Modern F1 (filial 1) type hybrid. Two specific parent varieties are bred to achieve a first generation hybrid offspring. F1 hybrids are not open-pollinated. Traditionally, “hybrid” indicates any variety that had been made by cross-pollinating, even if that was completed by hand or an insect.
Hyphae: Single, tubular filament of a fungal thallus or mycelium; the basic structural unit of a fungus.
Indeterminate: Describes tomato varieties that continue to grow and produce tomatoes all season until first frost: therefore, you can find tomatoes at all stages on the plant at one time. Also called “pole” tomatoes because supports are helpful in guiding plants that can easily reach 6′ or more.
Inflorescence: The structure that carry the flowers on a plant.
Inoculant: A substance containing beneficial soil microbes; commercial inoculants are used for a variety of purposes, from hastening the rate of decomposition in a compost pile to improving soil fertility.
Inoculum: Pathogen or its parts, capable of causing infection when transferred to a favorable location.
Insecticide: A substance used to control or kill insects.
Instar: The stage in an insect’s life history between any two moults; a newly-hatched insect which has not yet moulted is said to be a first-instar nymph or larva; the adult (imago) is the final instar.
Integrated Pest Management (IPM): A pest control strategy that uses an array of complementary methods: natural predators and parasites, pest-resistant varieties, cultural practices, biological controls, various physical techniques, and pesticides as a last resort. It is an ecological approach that can significantly reduce or eliminate the use of pesticides.
Intercropping: Planting more than one crop in an area at the same time.
Internode: The section of stem or rhizome between any two nodes.
Interplanting: See Companion Planting.
Interveinal: Between the leaf veins.
Invasive: Plants that spread aggressively and are difficult to eradicate.
Iron Chelate: A soil amendment that corrects chlorosis, a condition characterized by yellow leaves with green veins; iron chelate is available in both organic and synthetic forms.
Kelp Meal: A soil amendment made from dried, ground seaweed; it is a natural, organic source of potassium and numerous micronutrients
Larva: Young insect which is markedly different from the adult; caterpillars and fly maggots are good examples.
Lateral Bud: Bud forming along the side of a stem or branch rather than at the end.
Lateral Roots: Secondary roots that develop and grow from the primary root structure.
Lawn Substitute: Mat-forming plants that tolerate foot traffic; examples include clover, Roman chamomile, and thyme.
Layering: Treating a runner or shoot so it will form roots while still attached to the parent plant.
Leaching: The removal of salts and soluble minerals (nutrients) from the soil soil surface by flushing the soil with water due to gravity.
Leggy: Overly tall, stretched out seedlings. Usually more weak and prone to toppling. Prevent leggy seedlings by providing ample bright light.
Legume (Leguminous): A plant species within the Fabaceae (Leguminosae) family which creates symbiotic relationships with rhizobium (soil) bacteria to fix atmospheric nitrogen for growth.
Light soil: A soil that contains a high proportion of sand.
Ligule: Identifying feature on grasses; flat membrane or band of hairs arising from the inner surface of the leaf sheath, where it joins the leaf blade.
Lime: Calcium compounds, often applied to lower the pH of the soil (make it more alkaline); particularly useful when growing brassicas (cabbages, broccoli etc) to prevent club root disease.
Lobe: A segment of a cleft leaf or petal.
Long-Day Plant: Plants that form flowers only during summer, when there are more than 12 hours of light each day; these include spinach, lettuce and other plants that tend to “bolt” in early summer.
Medium: For horticultural purposes, a medium is the material plants grow in.
Macro-climate: The overall climate of a particular region.
Macronutrients: Nutrients required by plants for normal growth. Macronutrients such as nitrogen (N), phosphorus(P), and potassium (K) are needed in large quantities by most plants.
Maggot: Vermiform larva; a larva without legs and without well-developed head capsule.
Mandibles: Paired appendages or jaws, most commonly used in chewing insects to cut and crush food, or for defense; may be modified into a tube-like stylet in piercing-sucking insects such as aphids, leafhoppers and plant bugs.
Micro-climate: Can be applied to a variety of things. For our purposes, it is a spot within a garden that differs from the general environment. Some examples would be a wet spot where water collects during rain, a spot that remains warmer in the winter – often due to a structure, a spot that is sheltered from the wind, a spot that is affected by ocean salt spray etc.
Microgreen: Young, leafy vegetables or herbs that are harvested just above the soil line when the plants have their first pair of leaves, called cotyledons, and possibly the just-developing true leaves. AKA Sprouts.
Micro-Nutrients: Some mineral elements are needed by plants in very small quantities. If the plants you are growing require specific “trace elements” and they are not getting them through the soil, they must be added.
Milk Phase: Stage of development when the juice of the kernels on sweet corn ears appears milky.
Molting: The process of loosening/shedding the old cuticle ad producing a larger replacement.
Monoecious: The attribute of a plant producing both pollen-producing and pollen-receiving parts.
Mounded: Plants with a rounded appearance, they are usually wider than they are tall.
Moth: Insect closely related to the butterfly; they both belong to the order Lepidoptera. Moths, and particularly their caterpillars, are a major agricultural pest in many parts of the world.
Mulch: Any organic material, such as wood chips, grass clippings, compost, straw, or leaves that is spread over the soil surface (around plants). Mulch helps retain soil moisture, decreases weeds, reduces erosion, helps cool plant roots, adds organic matter (provided organic mulch is used), increases the attractiveness of the landscape, and protects plants from adverse summer or winter conditions. Read more about bagged and bulk mulch.
Mycelium: The network or mass of hyphae formed by fungi.
Mycorrhizae: Specialized fungi that colonize the root system of plants to form a mutually beneficial or symbiotic relationship, acting as extensions of the root system, increasing the surface area and exchange of nutrients and water between the soil and the plant’s roots.
Native: Specie or variety originating from an area or region.
Natural Enemies: Predators, parasitoids or pathogens that help to reduce pest numbers, sometimes keeping populations from reaching economic injury levels.
Natural Mulches: Mulches made from natural materials such as compost or bark.
Naturalization: Process of plants that have spread over a large area over time, whether by self-seeding or via creeping rhizomes.
Necrosis: (adj. necrotic) Death of cells or tissue, usually accompanied by black or brown darkening.
Nitrate: The form of nitrogen that plants use; easily lost through leaching.
Nitrogen: Essential nutrient responsible for green vegetative growth in plants (abbreviated N on fertilizer products); animal manures, blood meal, fish meal and freshly cut vegetation are common sources of organic nitrogen.
Nitrogen-Fixing: Plants that form a symbiotic relationship with soil microbes that chemically convert atmospheric nitrogen to a soluble form of nitrogen, the nutrient responsible for the rapid green growth.
Node: The location on the stem or rhizome where buds, leaves and branches are attached.
No-Till-Gardening: This type of gardening calls for no cultivation (or tilling) of the soil after the initial tilling. In its place, regular mulches are added and plants are planted through the mulch. This saves on labor and eliminates weeds, which might germinate as a result of tilling. Click on our no-dig vegetable gardening article and learn how working less makes growing easy (and maybe better).
Noxious Weed: Weeds that government agencies want to prevent from establishing in a particular area.
N-P-K: An abbreviation for the three main nutrients that have been identified as absolutely necessary for plants are nitrogen (N), phosphorus (P) and potassium (K). These three are also known as “macronutrients,” and are the source of the three numbers commonly found on fertilizer labels.
Nurse Plants: Plants that provide factors or serve as breeding grounds for beneficial insects, increasing populations of beneficial insects.
Nymph: Young stages of those insects which undergo a partial metamorphosis; the nymph is usually quite similar to the adult except that its wings are not fully developed and it normally feeds on the same kind of food as the adult.
Open pollinated: Varieties that produce seeds that are “true”, growing into nearly identical plants as the plant they were harvested from (if they are not cross pollinated).
Opposite Leaves: Arrangement of leaves on the stem placed two at a node, on opposing sides of a stem, immediately across from each other.
Organic: Refers to something derived from living organisms and is made up of carbon-based compounds. It is also a general term used for a type of gardening using no chemical or synthetic fertilizers or pesticides.
Organic Gardening: This method of gardening is based on building a healthy, living soil through composting and using supplemental nutrients from naturally occurring deposits. The basic principle is to feed the soil so the soil will feed the plants. Healthy plants are better able to resist pests and disease thus reducing the need for control. If control is needed, cultural and mechanical methods are used first. Naturally derived pesticides are used only as a last resort.
Organic Matter: Dead and decaying plant or animal tissues, including leaves, roots, manure, and the bodies of insects, earthworms, and microbes; compost piles are comprised primarily of organic matter, an essential ingredient of fertile soil.
Over Mulching: Applying too much mulch.
Oxygen starvation: Roots cannot get the oxygen they need.
Panicle: Type of inflorescence that usually has a central axis and many branches that are themselves more or less re-branched.
Parasite: Organism that spends all or part of its life in close association with another species, taking food from it but giving nothing in return. Ectoparasites live on the outside of their hosts, while endoparasites live inside the host’s body.
Parthenocarpic: The attribute of a variety producing fruit without fertilization. Cultivars produce seedless fruits when flowers are unpollinated, making them ideal for greenhouse production where pollinators may be excluded. When pollinated, these types produce seeded fruit.
Partial Sun or Partial Shade: 4 to 6 hours of direct sun a day.
Pathogen: An organism (such as fungus, bacterium, or virus) capable of causing a disease.
Peat: Partially degraded vegetable matter found in marshy areas. Peat is commonly used as a soil amendment.
Peat Moss: A common ingredient in potting soil, peat moss is the decomposed remains of plants that have collected at the bottom of bogs; this spongy material has exceptional water holding capacity and is also used lower the pH of soils for acid-loving plants.
Perennial: A plant that grows and flowers for years. They are either evergreens or may die back to the ground but will grow again the following season.
Perlite: A common ingredient in potting soil, perlite is a volcanic mineral that has been heated, causing it to puff up; perlite has exceptional water and air holding capacity, which helps to prevent soil from becoming compacted or drying out.
Permaculture: Principle that focuses on the intentional, careful design and maintenance of agriculturally-productive ecosystems (including garden spaces) to mimic the diversity, stability, and resilience of natural ecosystems.
Permanent Wilting Point: The point where a plant can no longer remove the small amount of water remaining in the soil and the plant wilts.
Pest: Plants, fungi, bacteria, nematodes, insects and animals that occur in a place they are not wanted.
Pesticide: A substance used to control or kill pests.
Petal Fall: The growth stage when petals begin to fall from the bloom.
Petiole: Stalk that attaches the leaf to the stem; a leafstalk.
pH: A scale from 0-14 that explains the degree of acidity or alkalinity of the water or soil. Soil pH is very important because it affects the availability of nutrients to plants and the activity of microorganisms in the soil.
Phloem: Nutrient-conducting vessels found throughout the plant. Phloem vessels transport nutrients produced in the foliage down through the stems, branches, or trunk to the roots.
Phosphorus: Essential nutrient involved in photosynthesis and various metabolic functions (abbreviated P on fertilizer products); bone meal and rock dust are the primary sources of organic phosphorus.
Photodegradable Mulch: Mulch that contains chemicals that cause the plastic to degrade when exposed to ultraviolet radiation.
Photoperiodism/Day Length Response: Refers to a reaction some organisms have to the length of day or night. In plants this reaction is usually flowering.
Photosynthesis: The process by which plants use the sun’s light to produce food (carbohydrates).
Photosynthetically Active Radiation: Wavelengths of radiation (mostly reds and some blues and yellows) used by plants for photosynthesis (production of sugars).
Pinching: Removing a portion of the plant, often just the very tip of the shoots, to encourage branching. Often this is done by using your finger nails to pinch off the newest growth but scissors, pruning shears, or a knife can also be used.
Pistil: The female seed-bearing organ of a flower, consisting of the ovary, style, and stigma.
Plasticulture: Growing system where plastic mulch is laid in beds on the soil surface, and crops are planted through small holes punched through the mulch; useful to reduce weeds, retain moisture and enhance earliness and harvest quality.
Pollination: The fertilization of a flower by wind, insect, birds, etc. where the male pollen reaches the female stigma, resulting in a seed, sometimes surrounded by an edible fruit like a pepper.
Pollinator: An organism that transfers pollen.
Propagation: The process of growing (creating) new plants through any variety of methods, including from seed, cuttings, grafts, or other plant parts.
Potassium: Essential nutrient involved in various metabolic functions in plants (abbreviated K on fertilizer products); greensand, kelp meal and wood ashes are the primary sources of organic potassium.
Primocane variety: Refers to the first-year stems of raspberries and blackberries. Autumn-fruiting raspberries will produce flowers and fruit on primocanes (they produce fruit in their first year of growth).
Predator: Insect that attacks and feeds on other insects, usually smaller and weaker than itself.
Preventative Weed Control: Practices whose aims are to prevent weeds from occurring in the garden.
Pruning: Using pruning shears, scissors, a knife, or loppers to shape or rejuvenate a plant, not to increase branching. Generally pruning is much more drastic than pinching. Pruning is most commonly used on shrubs, trees, and perennials.
Pupa: The 3rd life stage of some insect species, such as butterflies, beetles and flies. It occurs only in insects undergoing complete metamorphosis, during which the larval body is rebuilt into that of the adult insect. Typically a non-feeding and inactive stage.
Pupate/Pupation: To become a pupa.
Purity: The seed is true to type and does not contain undesirable contaminants.
Raised bed: A garden bed that is elevated off the ground.
Rhizome: An underground stem or runner that grows horizontally from nodes rather than vertically like most other plants.
Rhizobium bacteria: Bacteria that grow in close association with the roots of legumes and can convert atmospheric nitrogen into nitrate.
Rock Phosphate: A finely ground natural rock powder that is used to supply the soil with phosphate.
Roguing: Removal of diseased plants.
Rootball: The clump of roots and soil on a plant when removed from its pot.
Root Bound: A plant that has been in a pot a long time may have roots that circle around the edges of the pot. These roots may not grow out into the soil. To encourage good root growth cut or break up the roots to separate them.
Root Resistant Cultivars: Vegetable cultivars that are resistant to one or more disease, insect, nematode or virus.
Root Rot: Fungal disease caused by several different types of fungi that causes the roots of a plant to turn brown, grey, and/or slimy. Root rot impairs a plants ability to uptake water and will often kill plants that are infected. Root rot is often caused by chronic over-watering. The most common symptom of root rot is a plant that is wilting even though the soil is wet.
Rootstock: The underground part of a plant containing the roots. In grafting, a plant (scion) is joined to a desirable rootstock – often to promote a desired habit.
Rooting Hormone: Substances that help stimulate root growth on fresh cuttings during the propagation process, while also protecting the new cuttings from disease. Rooting hormone products can be purchased in a powder or gel form.
Row Cover: Fabric that is used to either exclude pests or raise temperatures of the area beneath it. Most of the time it is a type of poly-spun row cover material commonly used in farm and garden settings and it comes in several different thicknesses. Row covers may or may not have hoops under it to create a “low tunnel”.
Row Planting: Growing vegetables in single or double rows with aisles between each row.
Runner: A trailing stem growing above ground and rooting at the nodes, where plantlets are produced (e.g. strawberries). Some plants produce underground runners (=Rhizome).
Sand: Soil particles ranging in size between 0.2 to 2 mm.
Sanitation: Removing sources of pests so as few pests as possible get into your garden.
Scarification: The process of breaking through a hard outer covering of a seed to allow moisture to penetrate.
Scientific/Latin Name: The two or more part name that is unique to a specific species. Scientific names are consistent in any language, whereas a species may have several common names that may even vary by region.
Sudden leaf death or browning, either interveinally or at the margin that occurs when plants have difficulty taking up water or have sudden exposure to full sunlight following a wet, cloudy period.
Scouting: Regularly checking crops for pests and damage symptoms; looking in your garden to determine if pests are a problem.
Season Extender: Any technique or piece of equipment used to extend the growing season in both spring and fall. Examples include; row covers, greenhouses, hotbeds, cold frames etc.
Seaweed Meal: Seaweed that has been dried and ground into a fine powder. It contains many different compounds that may affect plant growth.
Seed: A dormant undeveloped plant.
Seed Coat: The outer “skin” on a seed that protects it from the environment.
Seed Heads: Pods or clusters of seeds on mature plants at the end of the growing season.
Seed Pod: A dry calyx containing a mature or maturing seed.
Seed Potatoes: Potato tubers grown specifically for starting new plants and producing potatoes.
Seedling: A plant that has just emerged from its seed.
Self-Cleaning : A term used when a plant sheds old blooms without human help. This is not the same as dead-heading which involves removing seed heads to prevent seed set.
Self-Fertile: A plant that does not need pollen from a second individual in order to fertilize and set fruit. See also Self-Pollinating.
Self-Pollinating: Plants with the ability to pollinate themselves, meaning they can produce fruit with their own pollen (as opposed to those that require the pollen of another plant of the same species), which is useful where space is limited; many fruit trees are not naturally self-pollinating (also referred to as self-fertile) though breeders have developed varieties to overcome this trait.
Self-Seeding: A plant’s ability to drop seeds that germinate successfully and grow into seedlings. The subsequent seedlings are often referred to as “volunteers”.
Semi-Determinate: Growth type of tomatoes that falls between determinate and indeterminate types. They produce a main crop that ripens within a couple weeks, but also continue to produce up until frost.
Sepal: One of the separate, usually green parts forming the calyx of a flower.
Short-Day Plant: Plants that form flowers only during spring or fall, when there are less than 12 hours of sun each day; these include onions, poinsettia and chrysanthemums.
Side Dress: Applying a strip of fertilizer along the side of a bed of established plants in order to maintain adequate nutrient levels through the end of the growing season.
Silt: Soil particles between 0.002 and 0.05 mm in size.
Slips: Cuttings taken from a mature Sweet Potato plant; used to grow a new crop.
Slow Release Fertilizer: Fertilizer that comes in pellets and is slowly released based largely on microbes which are more or less active based on soil temperatures.
Soil Amendment: Material added to the soil to improve its properties. This may include; water retention, permeability, water infiltration, drainage, aeration and structure. Soil amendments are mostly organic matter or very slow release minerals and are typically worked into the topsoil.
Soil Crust: A hard surface layer that can form on some soils after rains.
Soil-less media: A growth media not containing field soil.
Soil Test: A measurement of the major nutrients (nitrogen, phosphorous, and potassium) and pH levels in the soil.
Soil Texture: The coarseness or fineness of soil particles.
Soluble fertilizer: Fertilizer that dissolve easily in water and are immediately available for plant use.
Specimen Plant: Normally a tree or shrub grown in a prominent position where it can be viewed from different angles.
Species: Plants which are genetically similar and which breed true to type from seed.
Spiller: Plants placed along the edge of a combination container to spill or trail out of the pot.
Spindly: Excessive and weak stem growth due to exposure to adverse environmental conditions.
Spore: Reproductive structure of fungi and some other organisms, containing one or more cells; a bacterial cell modified to survive an adverse environment.
Spreading: Plants that grow low and spread along the ground, rooting at nodes along the stem.
Sprout: Germinated seeds that are not grown in medium but instead rinsed in water and drained several times a day.
Stamen: The male organ of a flower, consisting of the filament and the pollen-containing anther.
Staking: The practice of using a stick, pole, or other object to support a plant as it grows.
Standard: A tree or shrub that has been trained or grafted to a certain height with a long bare stem and foliage at the top (“Shrub-on-a-stem”).
Stippling: Numerous small, white or bronzed puncture marks on the leaf.
Stolon: Horizontal stem at or slightly below the soil surface that gives rise to new plants at its nodes and tips.
Stoma: (pl. stomata; adj. stomatal; also stomate) Structure composed of two guard cells and the opening between them in the epidermis (tiny pores) of a leaf or stem, functioning in gas exchange; oxygen, carbon dioxide, water vapor, and other gases move in and out of the leaf through these pores.
Stratification: The process of subjecting seed to a moist and cold treatment to break dormancy, which occurs naturally when seed is sown outdoors in the fall and experiences a winter period.
Stunting: Reduced plant growth due to a pest or a lack of water, nutrients or other necessity for plant development.
Subsoil: The infertile layer of soil beneath topsoil that contains minerals, but little to no biological activity or organic matter; also called mineral soil.
Succession Planting: Growing crops so that they mature at different times.
Successive Sowing: Sowing at least once more after the initial sowing, which extends the harvest. Three ways to successive sow:
- 1. Staggering sowings of the same crop;
- 2. Sowing two varieties of the same crop with different maturing dates;
- 3. Replacing one finished crop with a different crop.
Suckers: New shoot growth pushing from either the roots or the lateral branches, (sometimes called root suckers, or water sprouts.
Swale: A broad, shallow ditch used to collect water along a slope and encourage it to soak slowly into the ground; swales help to prevent erosion.
Taproot: The primary root; usually larger than the branch roots; and usually present in most annual and biennial plants.
Tassel: The structure at the tip of the corn plant, which is the male flower.
Tipburn: Yellowing and/or necrosis of the leaf tissue at the apex.
Tender Perennial: Plants that are perennial in warm locations but are not winter hardy in cold locations. These plants are often treated as annuals in cold climates or may be in the house plant section.
Terminal Bud: The portion of a plant where new growth originates from, most often in the center or top ‘leader’. If the terminal bud is cut, it often causes the plant to stop or slow upward growth and can encourage branching instead.
Thinning: Reducing seedlings so that remaining plants are spaced properly.
Thriller: Plants that are placed in the center or back of a combination planter to add drama and height to the combination.
Tilth: Describes the general health of the soil including a balance of nutrients, water, and air. Soil that is healthy and has good physical qualities is in good tilth.
Topdressing: Applying fertilizers or some kind of soil amendment after seeding, transplanting or once the crop has been established.
Topsoil: The upper layer of soil that you plant in. It varies in depth from place to place, but will almost always be less than a foot deep and can be as little as 2 inches deep
Toxicity: When a plant does not react well to something it is often called Toxicity. Toxicity could refer to too much fertilizer, too much sun, sensitivity to insecticides etc.
Trace Elements: Nutrients that plants need in small amounts. Common trace elements include Boron, Copper, Iron, Manganese, Molybdenum, and Zinc. These elements are usually included in most commercial fertilizers.
Trailing: Plants that trail along the ground or out of pots but do not root at nodes along the stem.
Movement of nutrient ions from the plant roots to shoots and other plant parts as part of transpiration (ie water flow through the plant).
Transpiration: Loss of water vapor from the plant.
Transplanting: The moving of a plant from one growth medium to another.
Trap Crops: Plants that attract insect pests keeping them away from the vegetable crop.
Trellis: Latticework that supports climbing plants.
Tuber: Swollen root or underground stem with storage tissue (e.g. a potato).
True-To-Type: The plants are actually the vegetable and variety the label indicates.
Upright: A plant that is taller than it is wide with straight (more or less) edges, these plants often have a somewhat spikey appearance.
Untreated Seed: Seed that does not have a chemical treatment such as fungicide applied to it.
Variegated Foliage: Foliage with different colors, usually but not always random, alternating on the foliage.
Variety: A botanical subdivision within a species. A species that has naturally formed a unique characteristic, for example from cabbage (Brassica oleracea) came kale (Brassica oleracea var. viridis) and kohlrabi (Brassica oleracea var. gongylodes) which both adapted unique, characteristics that differ from cabbage and so the variety (“var.”) name was added to the species name.
Vector: Organism which acts as a carrier of pathogens from plant to plant.
Vermicomposting: The use of red worms to convert food scraps or other organic materials into worm castings.
Vermiculite: A common ingredient in potting soil, vermiculite is a mica-like mineral that has been heated, causing it to expand into a spongy material with exceptional water and air holding capacity; it has similar properties as perlite.
Vine crops: Crops that produce vines that grow along the ground including watermelon, muskmelon and pumpkins.
Virus: Particles containing DNA or RNA that are much smaller than bacteria and require a host cell to multiply.
Vernalization: Cold treatment, such as found in cold winter conditions, that induces flowering in some varieties.
Viability: The percentage of seed that will germinate.
Volunteer: A plant that emerges from being self-sown or sown by an animal rather than by the gardener.
Watering: Plants differ on how much water they require and will generally fall into 5 categories. These categories are most relevant for plants in containers but also apply to in ground plantings.
- Dry – Water only when the soil is quite dry. Plants that prefer dry conditions may be susceptible to root rot disease if kept too wet. Dry plants will need little to no supplemental water once established if they are planted in the ground.
- Dry to Normal – Water when the top of the soil in a pot is dry to the touch but err on the side of dry rather than wet. While these plants will be more tolerant of moist conditions than Dry plants they still do not like constantly moist soil. Dry to Normal plants will need little to no supplemental water once established if they are planted in the ground.
- Normal – Water when the top of the soil in a pot is dry to the touch. For in ground plantings they will need some supplemental water if there is an extended dry spell but will not need constant watering.
- Normal to Wet – Water when the top of the soil in a pot is dry to the touch but err on the side of wet rather than dry. Plants that like Normal to Wet conditions will prefer that the soil be constantly moist and will not tolerate dry soils well. These plants are often good planted at pond edges. For in ground plantings you will need to provide an inch of water each week if mother nature doesn’t do it for you.
- Wet – These plants need soil that is constantly moist to wet. Plants in the wet category also will do well on pond edges or as pond plantings. They do not tolerate dry soils.
Waterlogged: The air spaces in the soil are filled with water.
Water Soluble Fertilizer: Fertilizer that either comes in liquid form or comes in crystal form that needs to be dissolved in water.
Weed: A plant growing where it is not wanted and where it adds no value.
Whorl: Three or more leaves or flowers at one node; with the parts encircling the stem and pointing outward like the spokes of a wheel.
Windbreak: A planting of (a row or multiple rows of)trees or shrubs which shelters an area from wind.
Worm Casting: The digested organic waste of red worms. Gardeners consider them the most nutrient dense organic compost available.
Xeriscaping: To create a low maintenance landscape with native plants and small or non-existent areas of turf grass. One of the primary goals of xeriscaping is to reduce landscape water use.
Xylem: Water-conducting vessels found throughout the plant. Xylem vessels transport water and minerals from the roots upward through the plant.