Garden Glossary

The chemical inhibition of one plant's growth by another, through compounds released into the soil or air. Some plants suppress nearby competitors; others are themselves suppressed by certain neighbors.

Small, soft-bodied insects in the superfamily Aphidoidea that feed by piercing plant tissue and extracting phloem sap. They reproduce rapidly through parthenogenesis and can reach damaging populations quickly, but are also targeted by many natural predators.

Insects that provide value in the garden by pollinating crops, preying on pest insects, or parasitizing pest species. Supporting beneficial insect populations is a core strategy in biological pest control.

Brief immersion of vegetables in boiling water (or steam) followed by rapid cooling in ice water. Required before freezing most vegetables to inactivate enzymes that cause quality loss during frozen storage.

A physiological disorder in tomatoes, peppers, and squash characterized by a dark, sunken, leathery lesion at the blossom end (bottom) of the fruit. Caused by calcium deficiency in developing fruit tissue, typically due to inconsistent watering rather than calcium-poor soil.

The rapid shift from vegetative growth to flowering and seed production, usually triggered by heat, lengthening days, or stress. Leaf quality drops sharply once a plant bolts.

A potentially fatal illness caused by the toxin of Clostridium botulinum, an anaerobic bacterium that can grow in improperly processed low-acid canned foods. The primary food safety reason that low-acid vegetables require pressure canning rather than water bath canning.

An unheated, bottomless garden structure with a transparent lid that functions as a passive solar collector, protecting plants from frost and cold winds and extending the growing season by 4-6 weeks on each end.

The practice of storing perishable food at low temperatures to slow microbial activity and metabolic processes, extending usable life. Includes refrigerator storage, root cellaring, and purpose-built cool rooms or refrigerated spaces.

Exposing seeds to a period of cold, moist conditions to break dormancy and trigger germination - mimicking the natural overwintering process many seeds require.

The intentional grouping of different plant species in the same space to improve growth, repel pests, attract beneficial insects, or make better use of space and resources.

Decomposed organic matter - kitchen scraps, yard waste, and plant material - broken down by microbial activity into a stable, humus-rich material that improves soil fertility, structure, and biological activity.

A crop grown primarily to benefit the soil rather than for harvest, used to prevent erosion, suppress weeds, fix nitrogen, add organic matter, or break pest and disease cycles between main cash crops.

The practice of planting different crop families in different garden beds each year to break pest and disease cycles, manage soil nutrients, and reduce the buildup of soilborne pathogens.

Decay of plant tissue at or just below the soil surface where the stem meets the root system. Caused by several soilborne pathogens including Sclerotinia, Phytophthora, and Rhizoctonia, typically promoted by excess moisture and poor drainage.

A post-harvest conditioning process that hardens the skin, heals surface wounds, and develops flavor in certain crops including winter squash, sweet potatoes, garlic, and onions. Proper curing dramatically extends storage life.

A seedling disease caused by several soilborne pathogens - primarily Pythium, Rhizoctonia, and Fusarium species - that rots stems at or below the soil line, causing seedlings to collapse shortly after emergence.

A plant type that flowers and fruits regardless of daylength, triggered by age or temperature rather than photoperiod. Includes most warm-season vegetables and certain strawberry varieties bred for continuous fruiting.

The average number of days from transplant date (or from direct sowing, where noted) until a crop is ready to first harvest under normal growing conditions.

A food preservation method that removes moisture from food to below the level that supports microbial growth, typically to 10-20% remaining water content. Extends shelf life for months to years when properly stored.

A plant growth habit, most commonly used for tomatoes, in which the plant grows to a fixed height, sets all its fruit within a defined period, and then stops growing. Determinate plants require minimal pruning and are suited for processing or one-time large harvests.

Planting seeds directly into their permanent garden location rather than starting them indoors and transplanting seedlings later.

The total amount of photosynthetically active radiation (PAR) delivered to a plant over a full day, measured in moles of photons per square meter per day (mol/m²/day). The most useful single metric for matching light conditions to crop requirements.

The first filial generation produced by crossing two distinct parent varieties. F1 hybrids are the direct offspring of a controlled cross and display hybrid vigor, but do not breed true from saved seed.

Microbial transformation of food through enzymatic activity, primarily by bacteria, yeasts, or molds. In vegetable preservation, fermentation usually refers to lactic acid fermentation by naturally occurring bacteria that preserve food and develop complex flavors.

The average calendar date of the last spring frost or first fall frost at a given location. Used to determine planting and harvest windows for frost-sensitive crops.

A genus of soilborne fungi responsible for several serious plant diseases including Fusarium wilt, crown rot, and damping-off. Fusarium wilts are particularly destructive because they colonize the vascular system, blocking water movement and causing rapid collapse.

Genetically Modified Organism - a plant, animal, or microorganism whose genetic material has been altered using recombinant DNA technology to introduce traits that would not occur through natural breeding.

Plant material - usually a cover crop - that is cut and incorporated into the soil while still green to decompose and add organic matter and nutrients to the soil rather than being harvested or composted.

An artificial light source designed to provide the spectrum and intensity needed for plant growth indoors. Used for seed starting, overwintering plants, and year-round indoor production. Quality is measured by light output (PPFD/DLI) and spectrum, not watts.

The process of gradually exposing indoor-started seedlings to outdoor conditions over 7-14 days before transplanting, reducing transplant shock and improving survival rates.

A geographic region defined by average annual minimum winter temperatures, used to determine which perennial plants can survive winter in a given location. Published by the USDA as the Plant Hardiness Zone Map.

The measured empty space left between the surface of food and the top of the jar in home canning. Correct headspace is essential for proper vacuum seal formation; too little or too much headspace prevents an adequate seal.

A plant variety that has been passed down through generations without crossing with other varieties, typically open-pollinated and with documented history, often bred before commercial hybrid development in the mid-20th century.

An unheated or minimally heated greenhouse-style structure made from bent conduit or pipe covered with greenhouse poly film. Extends the growing season by 6-8 weeks on each end and, in mild climates, can enable year-round production.

A plant produced by intentionally crossing two distinct parent varieties, often designated F1. Hybrids typically show vigor and uniformity but do not breed true from saved seed.

A plant growth habit, most commonly used for tomatoes, in which the plant continues growing, flowering, and producing fruit throughout the entire season until killed by frost or disease. Indeterminate plants require staking or caging and ongoing pruning.

A pest control philosophy that combines monitoring, prevention, biological controls, and targeted chemical intervention in a defined sequence - using the least disruptive approach that keeps pest populations below economic or aesthetic damage thresholds.

A growing method that maximizes yield per area by spacing plants closely enough that mature leaves just touch, suppressing weeds and making full use of available soil, water, and light.

The practice of growing two or more crop species simultaneously in the same space, either in alternating rows, mixed plantings, or with one crop understory to another. Aims to improve total yield per area and provide complementary benefits between crops.

Fermentation by naturally occurring Lactobacillus bacteria that convert sugars to lactic acid, preserving vegetables without vinegar or canning. The method behind sauerkraut, kimchi, traditional dill pickles, and fermented hot sauce.

A plant that flowers, bolts, or forms bulbs when the daily light period exceeds a critical threshold, typically 14-16 hours. In North American gardens, long-day responses occur during summer.

A localized zone within a larger climate area where temperature, humidity, wind, light, or frost frequency differs measurably from the surrounding area, often allowing different plants to thrive than would be possible in the general region.

Any material applied to the soil surface to retain moisture, suppress weeds, regulate soil temperature, or add organic matter. Common types include wood chips, straw, leaves, plastic film, and compost.

Microscopic roundworms in the phylum Nematoda. In gardening, the term most often refers to root-knot nematodes (Meloidogyne spp.), which damage crop roots, or beneficial entomopathogenic nematodes used to control soil-dwelling insect pests.

The biological conversion of atmospheric nitrogen gas (N2) into plant-available forms, primarily ammonium, carried out by specialized bacteria - most practically by Rhizobium bacteria in symbiosis with legume roots.

A variety pollinated by wind, insects, or other natural means, whose offspring reliably reproduce the parent's characteristics when grown under similar conditions. Seeds from open-pollinated varieties can be saved and replanted.

In agriculture, a production system certified under USDA National Organic Program (NOP) standards that prohibits synthetic pesticides, synthetic fertilizers, GMOs, and specified other inputs. In common usage, also refers to growing practices that avoid these inputs without formal certification.

A measure of soil acidity or alkalinity on a scale from 0 to 14, with 7 being neutral. Most vegetables grow best between pH 6.0 and 7.0. pH affects nutrient availability and microbial activity more than it directly affects plants.

The duration of light and dark in a 24-hour cycle. Many plants use photoperiod as a trigger for flowering, bulb formation, or dormancy, independently of temperature or season.

The physiological response of plants (and other organisms) to the relative length of light and dark periods in a 24-hour cycle. Controls flowering, bulbing, dormancy, and other developmental transitions in many vegetable and fruit crops.

A gardening or farming approach that intentionally grows multiple crop species together rather than a single species (monoculture). Mimics natural ecosystem diversity to reduce pest pressure and improve resilience.

A fungal disease that produces white or gray powdery growth on the surface of leaves, stems, and fruit. Unlike most fungal diseases, it thrives in warm, dry conditions rather than wet ones, and is caused by host-specific obligate fungi in the order Erysiphales.

A home canning method that uses steam pressure to raise the interior temperature of jars to 240-250°F, high enough to destroy Clostridium botulinum spores. Required for all low-acid foods including vegetables, meats, and beans.

A contained growing area built above ground level, filled with amended or imported soil mix, that improves drainage, warms earlier in spring, and allows precise control over soil quality.

A cool, dark, moderately humid underground or semi-underground space used for long-term storage of root vegetables, winter squash, apples, and other produce without refrigeration. Maintains temperatures of 32-50°F using ground insulation.

Lightweight spunbonded fabric laid over crops to provide frost protection, pest exclusion, or microclimate modification without blocking the light and air that plants need. Available in different weights for different levels of protection.

Intentionally abrading, nicking, or soaking a seed coat to allow water to penetrate and trigger germination in seeds with hard, impermeable coats.

Any technique that allows growing beyond normal frost-date boundaries, including cold frames, row cover, hoop houses, and low tunnels. Enables earlier spring planting and later fall harvests.

A plant that flowers, bulbs, or undergoes reproductive change when the daily light period falls below a critical threshold, typically 12-13 hours. In North American gardens, short-day crops respond to fall and winter light conditions.

Any material added to soil to improve its physical or chemical properties, including fertility, pH, drainage, water retention, or structure. Distinct from fertilizer, which is added specifically for plant nutrients.

A high-density planting method developed by Mel Bartholomew that divides a raised bed into one-foot squares, each planted with a specific number of plants based on mature plant size.

Staggering multiple sowings of the same crop at intervals of 2-4 weeks to spread the harvest over a longer season rather than producing one large glut.

The process by which water moves through a plant from roots to leaves and evaporates through pores called stomata. Drives nutrient uptake, cools leaf tissue, and accounts for the majority of water plants absorb.

A seedling started indoors or in a nursery and moved to its permanent growing location. Also the act of moving a plant from one location to another.

Compost produced through the digestive activity of earthworms, primarily red wigglers (Eisenia fetida), rather than thermal decomposition. Vermicompost is highly bioactive and contains elevated available nutrients compared to traditional compost.

The process by which a plant requires extended exposure to cold temperatures before it can flower or complete its reproductive cycle. Critical for biennials, many perennials, and crops like garlic and winter wheat.

A measure of the free (available) water in food, expressed on a scale of 0 to 1.0. Microbial growth, enzymatic activity, and spoilage reactions depend on water activity rather than total water content. Most pathogens cannot grow below water activity 0.85.

A home canning method that processes jars in boiling water at 212°F. Safe only for high-acid foods (pH 4.6 or below) including most fruits, jams, jellies, pickles, and acidified tomatoes. Not suitable for low-acid vegetables.

The loss of turgor pressure in plant tissue, causing drooping stems and leaves. Wilt can result from drought stress, root damage, vascular diseases (Fusarium wilt, Verticillium wilt, bacterial wilt), or other pathogens that disrupt water movement through the plant.