Glossary

Gardening glossary

Plain-English definitions of the growing terms you'll meet across the site. Heard a word you don't know? It's probably here.

A

AlliumPlant types: The onion family — onions, shallots, garlic, leeks and chives — grown for their pungent bulbs, stems or leaves and valued in crop rotation.
AnnualPlant types: A plant that completes its whole life cycle — germinating, flowering, setting seed and dying — within a single year.
Aphid (greenfly & blackfly)Pests & diseases: Small sap-sucking insects that cluster on soft growth, weakening plants, leaving sticky honeydew and spreading viruses.
AspectConditions & terms: The direction a plot or wall faces and the sunlight it gets — south- and west-facing spots are warmest and best for most crops.

B

BiennialPlant types: A plant that grows leaves and roots in its first year, then flowers, sets seed and dies in its second — like carrots, leeks and parsley left to run on.
BlanchingTechniques: Excluding light from stems — by earthing up or wrapping — to keep them pale, tender and mild, as with leeks and celery.
BlightPests & diseases: A fast-spreading disease (Phytophthora infestans) that rots the leaves, stems and fruit of potatoes and tomatoes in warm, wet weather.
Blossom end rotPests & diseases: A dark, sunken patch at the base of tomatoes, courgettes and peppers, caused by calcium failing to reach the fruit, usually from erratic watering.
BoltingSeeds & growth: When a plant flowers and runs to seed prematurely — usually triggered by heat, drought or stress — making leaves bitter and tough. Common in lettuce, spinach and rocket.
BrassicaPlant types: The cabbage family of vegetables — including cabbage, kale, broccoli, cauliflower, sprouts and turnips — grouped together for crop rotation because they share pests and feeding needs.
BroodyChickens: When a hen stops laying and sits tight on eggs (or an empty nest) trying to hatch them, driven by hormones — useful for hatching, frustrating if you only want eggs.

C

Carrot root flyPests & diseases: A low-flying fly whose larvae tunnel rusty channels through carrot and parsnip roots, drawn in by the smell of bruised foliage.
ChittingTechniques: Letting seed potatoes sprout short, sturdy green shoots before planting, to give them a head start and an earlier crop.
ChlorosisPests & diseases: Yellowing of leaves caused by a lack of chlorophyll, often from a nutrient shortage or, in blueberries, soil that is not acidic enough.
ClocheTechniques: A small, movable cover — glass, rigid plastic or fleece on hoops — placed over plants to warm the soil and shelter crops from cold, wind and pests.
ClubrootPests & diseases: A soil-borne disease that swells and distorts the roots of brassicas and badly stunts the plants; its spores persist in soil for many years.
Codling mothPests & diseases: A moth whose caterpillars tunnel into the cores of apples and pears, leaving maggoty fruit with a tell-tale hole.
Cold frameTechniques: A low, unheated box with a clear, sloping lid that traps warmth — used to harden off seedlings, raise early crops and overwinter tender plants.
CompostSoil & compost: Decomposed organic matter — kitchen and garden waste broken down into a dark, crumbly, sweet-smelling material that feeds soil and plants.
CordonTechniques: A plant trained and pruned to a single main stem — used for tall tomatoes grown up a cane, and for space-saving fruit trees grown at an angle.
Cotyledon (seed leaves)Seeds & growth: The first leaves to emerge from a germinating seed, usually simple in shape and different from the plant true leaves.
Crop rotationTechniques: Growing related crops in a different part of the plot each year to reduce the build-up of pests and diseases and balance soil use.
CucurbitPlant types: A member of the squash family — courgettes, cucumbers, pumpkins, squash and melons — grown for their fleshy fruit.
Cut-and-come-againPlant types: Harvesting salad and leafy crops by taking outer leaves or cutting the plant low, so it regrows for several more pickings.

D

Damping offSeeds & growth: A fungal disease that makes young seedlings collapse and rot at the base, encouraged by cold, wet, overcrowded conditions.
DeadheadingTechniques: Removing faded flowers to keep a plant tidy, prolong flowering and stop it putting energy into setting seed.
Determinate vs indeterminatePlant types: Bush (determinate) plants grow to a set size and crop in a flush; cordon (indeterminate) types keep growing and fruiting — a key distinction in tomatoes.
Direct sowingTechniques: Sowing seed straight into the ground where it is to grow, rather than raising plants in pots first.

E

Earthing upTechniques: Drawing soil up around the stems of a crop — most often potatoes — to protect shoots from frost, stop tubers greening, and encourage more to form.
EricaceousSoil & compost: Acidic, lime-free compost or soil (pH around 4.5–5.5) needed by acid-loving plants such as blueberries, which go yellow and unproductive in ordinary compost.
Ex-battery henChickens: A commercial laying hen rehomed at the end of its caged or barn life; ex-batts make rewarding pets and keep laying well with good care.

F

F1 hybridSeeds & growth: A first-generation seed produced by crossing two specific parent plants, giving vigorous, uniform, reliable plants — but seed saved from them will not come true.
First earlyPlant types: A fast-maturing potato (or other) variety ready to harvest early in the season, before second earlies and maincrop types.
ForcingTechniques: Excluding light from a plant such as rhubarb or chicory to draw up tender, pale, early stems or leaves ahead of the normal season.
Free-drainingConditions & terms: Soil or compost that lets excess water pass through quickly so roots are not left sitting wet — vital for Mediterranean herbs and many crops.
Free-rangeChickens: Poultry given daily access to range and forage outdoors rather than being confined, which is better for welfare and natural behaviour.
FriableSoil & compost: Soil with a loose, crumbly texture that breaks apart easily in the hand, ideal for sowing and root growth.

G

GerminationSeeds & growth: The moment a seed sprouts and begins to grow, triggered by the right mix of moisture, warmth and (for some seeds) light.
GraftingSeeds & growth: Joining the top growth (scion) of one plant onto the roots (rootstock) of another, used for fruit trees so the rootstock controls size.
Green manureSoil & compost: A fast-growing cover crop sown to protect and enrich bare soil, then dug in or cut down to add organic matter and, for legumes, nitrogen.
Grit (for chickens)Chickens: Insoluble flint grit that hens swallow to grind food in their gizzard, plus soluble oyster-shell grit that supplies calcium for strong eggshells.
Grow bagConditions & terms: A flat plastic bag filled with compost that you plant straight into, popular for tomatoes and cucumbers on a patio or in a greenhouse.

H

Hardening offTechniques: Gradually acclimatising indoor-raised seedlings to outdoor conditions over 7–10 days before planting them out, so the shock of wind, sun and cold does not check or kill them.
HardinessConditions & terms: How well a plant withstands cold; hardy plants survive UK winters outdoors, while half-hardy and tender ones need protection or warmth.
Heritage (heirloom)Plant types: An older, open-pollinated variety passed down over generations, grown for flavour, history or unusual looks rather than uniformity.
HumusSoil & compost: The dark, stable organic matter left when compost and plant material fully break down, which holds moisture and nutrients in the soil.

J

John InnesSoil & compost: A range of loam-based composts made to standard recipes (No.1 to No.3) suited to seeds, potting and long-term container plants.

L

Last frostConditions & terms: The average date of the final frost of spring in your area — the point after which tender crops can safely go outside.
Leaf mouldSoil & compost: Crumbly, dark material made from rotted-down autumn leaves, used as a soil improver, mulch or seed-compost ingredient.
Leggy seedlingsSeeds & growth: Pale, stretched, weak seedlings caused mainly by too little light, which makes them reach for it and topple easily.
LegumePlant types: A member of the pea and bean family that fixes nitrogen from the air through its roots, enriching the soil for the crops that follow.
LoamSoil & compost: The ideal garden soil — a balanced mix of sand, silt and clay that holds moisture and nutrients while still draining freely.

M

MaincropPlant types: A slower-maturing variety grown for a main, storable harvest, as opposed to quick early types; used especially for potatoes and carrots.
MoultingChickens: The annual shedding and regrowth of feathers, usually in autumn, during which hens stop or slow laying while they regrow their plumage.
MulchSoil & compost: A layer of material — compost, bark, leaf mould or straw — spread on the soil surface to lock in moisture, suppress weeds and feed the soil as it breaks down.

N

No-dig gardeningTechniques: A way of gardening that avoids digging the soil. Instead you spread compost on the surface and let worms and weather work it in, protecting soil structure and suppressing weeds.

O

OverwinteringTechniques: Keeping a plant alive through winter, outdoors with protection or under cover, so it crops earlier or survives to the next year.

P

Peat-freeSoil & compost: Compost made without peat, using composted bark, wood fibre, coir and green waste, to avoid damaging peat bogs.
PerennialPlant types: A plant that lives for several years, regrowing each season — unlike annuals, which grow, set seed and die in a single year.
PerliteSoil & compost: Lightweight white granules of expanded volcanic glass added to compost to improve drainage and aeration.
Pinching outTechniques: Removing the soft growing tip of a plant with finger and thumb to encourage bushier growth, or on a cordon tomato to stop it.
Point of layChickens: A young hen (pullet) at around 16–22 weeks old, just about to start laying eggs — the most popular age to buy when starting a backyard flock.
PollinationTechniques: The transfer of pollen that lets a flower set fruit — done by insects, wind or by hand — essential for crops like courgettes, beans, tomatoes and fruit trees.
Potting onTechniques: Moving a growing plant into a larger pot once it has outgrown its current one, to give the roots more room.
Powdery mildewPests & diseases: A fungal disease that coats leaves in a white, dusty bloom, common in late summer on courgettes, squash and peas when roots are dry.
Pricking outTechniques: Carefully lifting tiny seedlings from a seed tray and moving them into individual pots or modules once they have their first true leaves.

R

Raised bedConditions & terms: A growing bed built up above the surrounding ground, usually framed and filled with compost, giving better drainage, warmth and control.
Red miteChickens: A tiny blood-sucking parasite that hides in coop cracks by day and feeds on chickens at night — the most common pest of backyard hens, worst in warm months.
RootstockSeeds & growth: The root system a fruit tree is grafted onto, which controls its eventual size and vigour — letting you grow full-size apples on a small, garden-friendly tree.
RunnerSeeds & growth: A long, trailing stem that a plant such as a strawberry sends out, which roots where it touches the soil to form a new plant — a free way to propagate.
RustPests & diseases: A fungal disease that marks leaves with orange or brown pustules, seen on alliums like leeks and garlic in damp conditions.

S

ScionSeeds & growth: The upper, fruiting part of a grafted plant that determines the variety, joined onto a separate rootstock.
Seed viabilitySeeds & growth: Whether seed is still alive and able to germinate; viability declines with age and varies by crop, which is why fresh seed is more reliable.
Side-shootingTechniques: Removing the shoots that grow between the main stem and leaves of a cordon tomato, to channel energy into fruit.
Slug & snailPests & diseases: Soft-bodied molluscs that feed at night and can shred seedlings and leafy crops, especially in warm, damp weather.
Soil pHSoil & compost: A measure of how acidic or alkaline soil is on a 0–14 scale; most vegetables prefer a slightly acidic to neutral pH of about 6.0–7.0.
StakingTechniques: Supporting a tall or top-heavy plant with a cane, stake or framework so it does not flop or snap.
Successional sowingTechniques: Sowing small amounts of a fast crop every few weeks rather than all at once, so you harvest a steady supply instead of a glut followed by a gap.

T

Tender vs hardyPlant types: Tender plants are killed or damaged by frost (like tomatoes and courgettes); hardy plants withstand cold — the line that governs when to plant out.
ThinningTechniques: Removing surplus seedlings so the remaining plants have enough room, light and food to grow to full size.
TilthSoil & compost: The crumbly, fine texture of well-prepared topsoil — like coarse breadcrumbs — that seeds germinate and root into easily.
TransplantingTechniques: Moving a young plant from where it was raised into its final growing position.
True leavesSeeds & growth: The second set of leaves a seedling produces, which resemble the adult plant and signal it is ready to prick out.

V

VermiculiteSoil & compost: A light, spongy mineral added to compost to hold moisture and air, and often used to cover seeds for even germination.
VernalisationSeeds & growth: The cold period some plants need before they will flower or bulb up; a mistimed cold spell can also trigger premature bolting.
Vine weevilPests & diseases: A beetle whose adults notch leaf edges and whose grubs eat roots, especially of plants grown in pots like strawberries.

W

WaterloggedConditions & terms: Soil saturated with water so that air is driven out and roots suffocate and rot; common on heavy clay or compacted ground.