📖 Gardening Glossary
40+ common gardening terms explained in plain English. No jargon, no gatekeeping — just clear, simple definitions.
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Allelopathy
When one plant releases chemicals that slow down or stop the growth of nearby plants. It's nature's way of reducing competition. Black walnut trees are the most famous example — they release a chemical called juglone that many garden plants can't tolerate.
See also: companion planting
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Biennial
A plant that takes two years to complete its life cycle. In year one, it grows leaves and roots; in year two, it flowers, sets seed, and dies. Examples: carrots (if left to flower), parsley, kale (technically a biennial grown as an annual).
Blanching (Gardening)
Blocking light from reaching a plant's stems or leaves to keep them pale, tender, and less bitter. Gardeners do this with celery (by mounding soil around the stalks), cauliflower (tying leaves over the head), and endive (covering with a pot).
See also: bolting
Bolting
When a plant suddenly shoots up a tall flower stalk and tries to produce seeds — usually triggered by hot weather or long days. Once a plant bolts, the leaves often turn bitter and tough. Common in lettuce, spinach, cilantro, and basil.
See also: blanching, cool-season crop
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Companion Planting
The practice of growing certain plants near each other because they benefit one another — by repelling pests, attracting pollinators, improving flavor, or providing shade and support. The classic example is the "Three Sisters": corn, beans, and squash grown together.
See also: allelopathy, nitrogen fixer
Compost
Decomposed organic matter (kitchen scraps, leaves, grass clippings) that turns into dark, crumbly, earthy-smelling material. Compost improves soil structure, feeds beneficial microbes, and adds slow-release nutrients. Often called "black gold" by gardeners.
Cool-Season Crop
Plants that grow best in the cooler temperatures of spring and fall. They can tolerate light frosts and often bolt (go to seed) when summer heat arrives. Examples: lettuce, spinach, peas, radishes, kale, broccoli.
See also: warm-season crop, bolting
Cover Crop
A crop grown primarily to protect and improve the soil rather than to harvest. Cover crops prevent erosion, suppress weeds, and add organic matter. Common examples: winter rye, clover, buckwheat, hairy vetch.
See also: green manure, nitrogen fixer
Crop Rotation
The practice of planting different types of crops in the same spot each year to prevent pest build-up and soil nutrient depletion. A simple rotation: follow heavy feeders (tomatoes, corn) with nitrogen-fixing legumes (beans, peas), then light feeders (lettuce, herbs).
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Determinate (Tomatoes)
A tomato variety that grows to a fixed height, produces all its fruit in a short burst (2–4 weeks), and then stops. Great for containers, canning, and people who want a big harvest all at once.
See also: indeterminate
Direct Sow
Planting seeds directly into the garden soil where they will grow, rather than starting them indoors. Crops that hate root disturbance (beans, carrots, radishes, peas) are best direct-sown.
See also: transplant, hardening off
Dynamic Accumulator
A plant with deep roots that "mines" nutrients from deep in the soil and brings them to the surface in its leaves. When the leaves drop and decompose, those nutrients become available to shallower-rooted plants. Examples: comfrey, yarrow, dandelion, borage.
See also: nitrogen fixer, compost
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Frost Date
The average date of the last spring frost and the first fall frost for your location. Your growing season is the window between these two dates. These are averages — actual frost can come earlier or later — so check the forecast.
See also: hardiness zone, planting calendar
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Germination
The process by which a seed wakes up from dormancy and begins to sprout — triggered by water, warmth, and sometimes light. Most vegetable seeds germinate in 5–14 days when soil temperatures are right. The seed packet usually lists the days to germination.
See also: direct sow, transplant
Green Manure
A cover crop that is grown and then tilled or chopped back into the soil while still green and living. It adds organic matter and nutrients, improving soil fertility for the next crop. Buckwheat, clover, and alfalfa are popular choices.
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Hardening Off
The process of gradually exposing indoor-grown seedlings to outdoor conditions over 7–10 days before transplanting. You start with an hour of shade outdoors and slowly increase time and sun exposure. This prevents transplant shock.
See also: transplant, direct sow
Hardiness Zone
A geographic area defined by its average minimum winter temperature (USDA zones 1–13 in North America). Knowing your zone helps you choose perennials that will survive winter and figure out when to plant annuals. Most of the US is zones 4–9.
See also: frost date, planting calendar
Heirloom
A plant variety that has been passed down through generations (usually 50+ years), grown from open-pollinated seed, and selected for flavor, hardiness, or appearance rather than shelf life or shipping durability. You can save heirloom seeds and they'll grow true to type.
See also: open-pollinated, hybrid
Humus
The dark, stable, fully decomposed organic matter that remains after compost and mulch have broken down completely. Humus is what gives rich soil its crumbly texture and ability to hold water and nutrients.
Hybrid (F1)
A plant bred by deliberately crossing two different parent varieties to combine their best traits — like disease resistance, uniform size, or extra sweetness. Seeds saved from hybrids won't reliably produce the same plant next year.
See also: heirloom, open-pollinated
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Indeterminate (Tomatoes)
A tomato variety that keeps growing and producing fruit all season long until frost kills it. These plants get tall (6–10 feet), need sturdy support (staking or caging), and give you a steady supply rather than one big harvest. Most heirloom tomatoes are indeterminate.
See also: determinate
Intercropping
Growing two or more crops in the same space at the same time — often a fast crop between slower ones. For example, planting radishes (25 days) between rows of carrots (70 days). The radishes are harvested before the carrots need the space.
See also: companion planting, succession planting
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Legume
A plant family (Fabaceae) whose members form a partnership with soil bacteria to pull nitrogen from the air. Most legumes have pods with seeds inside. Garden examples: peas, beans, lentils, clover, alfalfa, and peanuts.
See also: nitrogen fixer, cover crop
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Mulch
A layer of material spread on top of the soil around plants. Organic mulches (straw, wood chips, shredded leaves) suppress weeds, retain moisture, regulate soil temperature, and break down to feed the soil. Inorganic mulches (landscape fabric, gravel) only suppress weeds and retain moisture.
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Nitrogen Fixer
A plant (usually from the legume family) that partners with soil bacteria to pull nitrogen from the air and convert it into a form plants can use — storing it in root nodules. When the plant dies back, that nitrogen becomes available to nearby plants. Examples: peas, beans, clover, alfalfa.
No-Till Gardening
A method of gardening where you never dig, turn, or till the soil. Instead, you add compost and mulch on top and let worms and soil life do the mixing. No-till preserves soil structure, beneficial fungi, and earthworm tunnels — and means fewer weeds.
NPK
The three numbers on fertilizer bags, standing for Nitrogen (N), Phosphorus (P), and Potassium (K). N = leafy green growth, P = roots and flowers/fruit, K = overall health and disease resistance. A 10-10-10 fertilizer has equal parts of all three.
See also: pH, nitrogen fixer
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Open-Pollinated
A plant variety that is pollinated naturally by wind, insects, or self-pollination. Seeds saved from open-pollinated plants will grow into plants that look and taste like the parent — unlike hybrids. All heirlooms are open-pollinated, but not all open-pollinated varieties are heirlooms.
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Perennial
A plant that lives for more than two years, coming back each spring from the same root system. In cold climates, the top growth may die back in winter but the roots survive. Examples: asparagus, rhubarb, rosemary (in warm zones), fruit trees, mint.
pH (Soil)
A measure of how acidic or alkaline your soil is, on a scale from 0 (very acidic) to 14 (very alkaline), with 7 being neutral. Most vegetables prefer slightly acidic soil (6.0–7.0). If the pH is too far off, plants can't absorb nutrients even if they're present in the soil.
See also: NPK
Pollinator
An animal (usually bees, butterflies, moths, or hummingbirds) that moves pollen from one flower to another, enabling fruit and seed production. Many garden plants — including squash, cucumbers, and fruit trees — depend on pollinators. Planting flowers nearby helps attract them.
See also: companion planting, open-pollinated
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Raised Bed
A garden bed built above ground level, usually framed with wood, stone, or metal, and filled with soil. Raised beds warm up faster in spring, drain better, reduce bending, and let you control soil quality completely.
Row Cover
A lightweight, breathable fabric laid over plants to protect them from frost, insects, and harsh sun. Unlike plastic, row covers let water and light through. Use them in spring to extend the season and in summer to block pests.
See also: frost date, hardening off
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Soil Amendment
Any material you mix into soil to improve it — compost adds organic matter, lime raises pH, sulfur lowers pH, sand improves drainage for clay soils, and perlite adds aeration for containers.
Succession Planting
Staggering plantings of the same crop every 2–3 weeks so you get a continuous harvest instead of everything at once. Essential for lettuce, beans, and cilantro. Also means planting a new crop in the same spot right after harvesting the previous one — like fall kale after spring peas.
See also: intercropping, cool-season crop
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Transplant
Moving a young plant from one place to another — most often from an indoor pot to the garden. Crops like tomatoes, peppers, and basil are commonly started indoors and transplanted out after the last frost.
See also: hardening off, direct sow
Trap Crop
A plant grown specifically to lure pests away from your main crops. The pests gather on the trap crop instead, and you either sacrifice it or treat it. Example: planting nasturtiums to attract aphids away from your vegetables.
See also: companion planting
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Volunteer
A plant that pops up on its own from last year's dropped seeds — not something you intentionally planted. Volunteer tomatoes, squash, and dill are common surprises. They're free plants, but they may not grow where you want them!
See also: open-pollinated, heirloom
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Warm-Season Crop
Plants that need warm soil and air temperatures to thrive. They are killed or damaged by frost and should be planted after your last spring frost date. Examples: tomatoes, peppers, beans, corn, squash, cucumbers.
See also: cool-season crop, frost date
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Zone (Hardiness)
See hardiness zone.