Gardening Glossary UK

Plain-English definitions of the growing terms you'll encounter on seed packets, in gardening books, and across this site.

A

Annual

A plant that completes its full life cycle in one growing season. Examples: lettuce, radishes, French beans.

Aspect

The direction a bed faces. South-facing gets the most sun in the UK.

B

Bolt

When a plant prematurely produces flowers and seeds. Makes leaves bitter and reduces harvest. Common in lettuce, spinach, and beetroot.

Brassica

Plant family including cabbages, kale, Brussels sprouts, broccoli, turnips, swede, and radishes. All susceptible to club root.

C

Chitting

Pre-sprouting seed potatoes in a light, frost-free location before planting.

Cloche

A cover placed over plants to trap warmth and protect from frost, wind, and pests.

Crop rotation

Moving plant families to different beds each year to prevent build-up of soil-borne pests and diseases.

F

F1 hybrid

First-generation cross between two parent plants, bred for uniformity and disease resistance. Saved seeds will not breed true.

Frost hardy / Frost tender

Hardy = survives below 0°C (kale, leeks). Tender = killed by frost (tomatoes, courgettes, basil).

H

Hardening off

Gradually acclimatising indoor-raised seedlings to outdoor conditions over 7–14 days before transplanting.

L

Last frost date

The average date of the final frost in spring. In most of the UK: mid-April to mid-May. Tender crops must not go outside before this.

Legume

Plant family (peas, beans, clover) that fixes nitrogen from the air into soil. Excellent predecessors for hungry crops like brassicas.

S

Succession sowing

Sowing small amounts of the same crop every 2–3 weeks to spread harvest over a longer period and avoid a glut.

Sets

Small immature bulbs for planting onions, shallots, and garlic. Easier and faster than growing from seed.

T

Tilth

The physical condition of soil — a fine, crumbly tilth is ideal for seed sowing.

Thinning

Removing excess seedlings to give remaining plants enough space, light, and nutrients.