Gardening glossary
Clear meanings for the words gardeners use
Look up seed packet language, soil terms, plant science, timing concepts, and common labels. Search the list or browse by category.
Showing 75 of 75 terms
plant labels
Annual
An annual is a plant that completes its life cycle from seed to flower and seed within one growing season. Learn how annuals differ from perennials and biennials.
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Aphid
An aphid is a small sap-feeding insect that can cluster on young growth and spread plant viruses. Many aphids also have natural predators.
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Apical dominance
Apical dominance is the tendency of a plant's main growing tip to suppress growth from buds lower on the stem and limit branching.
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Beneficial insect
A beneficial insect helps a garden by pollinating flowers, eating pests, decomposing material, or supporting another useful ecological process.
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Biennial
A biennial is a plant that normally needs two growing seasons to complete its life cycle, usually growing leaves first and flowering in the second season.
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Blight
Blight is a rapid browning, wilting, or death of plant tissue caused by different diseases or stresses. The term alone does not identify one pathogen.
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Bolting
Bolting is the rapid production of a flowering stalk by a leafy vegetable or herb. Learn why heat, day length, and plant stress can end the harvest.
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Cation exchange capacity
Cation exchange capacity, or CEC, describes how much positively charged nutrient a soil can hold and exchange with plant roots.
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Chill hours
Chill hours describe the amount of cool winter exposure some fruit plants need before they can flower and grow normally in spring.
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Chlorosis
Chlorosis is the loss of green color from leaves because chlorophyll is reduced. It can result from nutrient, root, disease, light, or environmental problems.
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Companion planting
Companion planting means growing different plants near one another to manage space, timing, habitat, or a specific interaction. Pairing charts are not universal rules.
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Compost
Compost is organic material that has decomposed under managed conditions into a stable soil amendment. Learn what finished compost can and cannot do.
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Cotyledon
A cotyledon is a seed leaf that supplies or helps produce food for a young seedling before its mature leaves take over during early growth.
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Crown
A plant crown is the area where roots meet stems or leaves. It is a sensitive growth point that should be planted at the correct depth.
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Cultivar
A cultivar is a cultivated plant selection maintained for identifiable traits such as color, size, flavor, growth habit, or disease resistance.
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Damping off
Damping off is a group of seedling diseases that cause young stems or roots to collapse, often in cool, wet, poorly ventilated growing conditions.
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Days to maturity
Days to maturity is the approximate time from a stated starting point until a crop reaches the harvest stage described by the seed company or plant source.
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Deadheading
Deadheading is removing spent flowers before or after seed develops. Learn when it can extend bloom, improve appearance, or prevent unwanted reseeding.
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Determinate
Determinate tomatoes grow to a relatively defined size, set much of their fruit in one period, and are often suited to containers or short harvest windows.
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Direct sowing
Direct sowing means planting seed where the crop will grow instead of starting it in a container and transplanting it later. Learn when direct sowing works best.
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Disease triangle
The disease triangle describes how a susceptible host, a disease-causing organism, and suitable environmental conditions must overlap for disease to develop.
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Drainage
Drainage is the movement of excess water through or away from soil. Good drainage keeps roots supplied with water without leaving the root zone saturated.
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First frost date
A first frost date estimates when a location may experience its first autumn freeze. Use it to plan harvest and protection, not as a guarantee.
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Frost tolerant
Frost tolerant describes a plant that can survive or continue growing through some freezing conditions, although tolerance varies by species, stage, and duration.
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Germination
Germination is the process in which a viable seed resumes growth and produces a root and shoot. Learn what seeds need and how to improve emergence.
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Grafting
Grafting joins part of one plant to the rooted part of another so their tissues can grow together as one plant with shared functions.
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Growing degree days
Growing degree days estimate heat accumulation over time and help predict development stages for plants and some insect pests.
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Hardening off
Hardening off is the gradual process of acclimating indoor-grown seedlings to outdoor light, wind, temperature, and watering conditions before transplanting.
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Hardiness zone
A hardiness zone groups locations by average annual extreme minimum temperature. Learn what the USDA zone can tell you and what it cannot predict.
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Hardpan
Hardpan is a dense soil layer that restricts roots, air, and water movement. It can form naturally or result from compaction and repeated traffic.
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Heirloom
Heirloom describes a plant variety preserved and passed through growers over time. It is not a universal legal definition or performance guarantee.
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Hybrid
A hybrid is offspring from parents with different genetic backgrounds, often bred for traits such as vigor, uniformity, flavor, or disease resistance.
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Indeterminate
Indeterminate tomatoes keep extending stems and producing flower clusters while conditions remain favorable. Learn how this growth habit changes support and pruning.
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Integrated pest management
Integrated pest management, or IPM, is a decision process that combines monitoring, prevention, identification, and targeted controls to manage pests.
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Internode
An internode is the section of stem between two nodes. Its length affects plant shape, spacing between leaves, and whether growth looks compact or stretched.
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Landrace
A landrace is a locally adapted population shaped by long-term selection and environmental conditions rather than one uniform breeding standard.
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Last frost date
A last frost date is a probability-based estimate of when a location is likely to experience its final spring freeze. It is a planning date, not a guarantee.
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Loam
Loam is a soil texture with a balanced mix of sand, silt, and clay. Learn why loam can hold water and nutrients while still draining and working well.
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Microclimate
A microclimate is the temperature, moisture, wind, and light pattern in a small area that differs from the surrounding climate.
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Mulch
Mulch is a protective layer placed on the soil surface to reduce evaporation, suppress weeds, moderate temperature, or protect soil structure.
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Mycorrhizae
Mycorrhizae are associations between plant roots and fungi. The fungi receive plant carbohydrates and can improve access to water or nutrients in some conditions.
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Native plant
A native plant is a species or variety that occurs naturally in a defined region without human introduction. Learn why the region and purpose of the label matter.
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Nitrogen fixation
Nitrogen fixation is the conversion of atmospheric nitrogen into forms plants or soil organisms can use, often through bacteria associated with legume roots.
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Node
A node is a point on a plant stem where leaves, buds, branches, or roots can develop. Nodes help gardeners understand pruning and propagation.
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NPK
NPK stands for nitrogen, phosphorus, and potassium, the three numbers on a fertilizer label that state the percentage by weight of each nutrient.
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Nutrient deficiency
A nutrient deficiency occurs when a plant cannot obtain enough of an element for normal growth. Symptoms depend on the nutrient, crop, roots, and soil conditions.
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Open-pollinated
Open-pollinated describes a variety that produces seed through natural pollination and can reproduce its traits when properly isolated and selected.
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Organic
Organic can describe a certified production system that follows defined rules, or materials derived from living organisms. The context matters.
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Organic matter
Organic matter is material derived from living organisms at different stages of decomposition. It influences soil structure, water, nutrients, and biological activity.
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Perennial
A perennial is a plant that can live and grow for multiple years, although its top growth may die back seasonally. Learn what the label does and does not promise.
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Photoperiod
Photoperiod is the pattern of light and darkness a plant experiences each day. It can influence flowering, dormancy, and seasonal growth in some species.
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Pollination
Pollination is the transfer of pollen to the receptive part of a flower, allowing fertilization and seed or fruit development in many plants.
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Powdery mildew
Powdery mildew is a group of fungal diseases that forms pale, powdery growth on plant surfaces. Learn why airflow and plant conditions affect it.
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Pruning
Pruning is the selective removal of plant parts to manage size, shape, health, safety, flowering, or fruiting. The correct cut depends on the plant and goal.
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Root rot
Root rot is the decay of plant roots, often associated with saturated soil, poor drainage, or disease-causing organisms.
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Root-bound
Root-bound describes a container plant whose roots have filled the available space and begun circling or forming a dense mat.
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Runner
A runner is a horizontal stem that grows from a plant and can produce a new plant at a node, as in strawberries and some grasses.
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Scale insect
A scale insect is a sap-feeding insect that often appears as a small bump or shell attached to stems, leaves, or fruit and weakens plants.
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Scarification
Scarification is the careful weakening of a hard seed coat so water can enter and germination can begin. Learn when this seed treatment helps and when to avoid it.
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Seed dormancy
Seed dormancy is a condition in which a living seed does not germinate even when some basic conditions appear suitable. Learn why dormancy can be useful.
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Seed viability
Seed viability is the ability of a seed to remain alive and capable of germinating under suitable conditions. It is different from germination speed or vigor.
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Soil aggregate
A soil aggregate is a cluster of sand, silt, clay, organic matter, and biological material held together as a crumb or soil structural unit.
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Soil pH
Soil pH measures how acidic or alkaline a soil solution is. It affects nutrient availability and should be interpreted with the crop and a reliable soil test.
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Soil salinity
Soil salinity is the concentration of dissolved salts in soil water. High salinity can make water harder for roots to absorb and injure sensitive plants.
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Soil texture
Soil texture is the relative proportion of sand, silt, and clay particles. It affects drainage, water storage, root growth, and nutrient holding.
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Stratification
Stratification is a period of controlled warm or cold conditions that helps some dormant seeds become able to germinate. Learn how it differs from scarification.
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Succession planting
Succession planting is a system of scheduling repeated sowings or follow-up crops so one garden space produces several harvests over a season.
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Tendril
A tendril is a slender plant structure that coils around support and helps a climbing plant hold itself up as stems extend.
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Tilth
Tilth describes the physical condition of soil for plant growth, including crumb structure, pore space, moisture, and ease of root growth.
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Transplant shock
Transplant shock is temporary stress after a plant is moved, often shown by wilting or slowed growth while damaged or disturbed roots recover.
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True leaves
True leaves are the first leaves that resemble the mature foliage of a plant and develop after the seedling's cotyledons.
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Variety
Variety can mean a named plant type in everyday garden language, or a formal botanical rank below species. Read the surrounding label to know which meaning applies.
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Vernalization
Vernalization is the exposure to cool conditions that enables some plants to flower. Learn why winter temperature can affect bulbs, biennials, and cool-season crops.
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Water-holding capacity
Water-holding capacity is the amount of water soil can store for plant use after excess water has drained away from the root zone.
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Whitefly
A whitefly is a small sap-feeding insect that gathers beneath leaves, produces honeydew, and may spread plant viruses between plants.
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