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Gardening glossary

Row cover (floating fleece)

Row cover, sold in the UK as horticultural fleece and in the US as floating row cover or Reemay, is one of the highest-leverage tools in a kitchen garden. The fabric is light enough to lay loosely on top of crops without crushing them — they grow up underneath, lifting the fleece as they go. Light penetrates at roughly 85–95%; water drains through; air circulates. What stays out is wind, flying pests, and the bottom 2–6 °C of cold air.

The three uses:

**1. Frost protection.** - Lightweight fleece (17 g/m²) gives roughly 2 °C of frost protection. - Medium fleece (30 g/m²) gives 4 °C. - Heavy fleece (50 g/m² or doubled fleece) gives 5–6 °C. This is what extends the autumn crop of lettuce, kale, and spring onions deep into winter in mild UK climates and rescues spring transplants from a surprise late frost.

**2. Insect exclusion.** Carrot fly, cabbage white butterfly, leek moth, leaf miner, and aphids cannot reach the crop through a properly sealed fleece. The cover must be down before adults emerge — for carrot root fly, that means before mid-May in most of the UK — and edges must be buried or weighted down so insects cannot crawl under.

**3. Wind and cold-soil moderation.** Newly planted brassicas, strawberries, and beans benefit from a couple of weeks under fleece. Soil under fleece warms 1–3 °C faster in spring, accelerating germination and root development.

How to use it well:

- **Float, don't pin tight.** Allow slack for crops to lift the fabric as they grow. Tight fleece bends and damages young shoots. - **Bury or weight edges.** Soil, stones, or sandbags every metre along the perimeter. Pegs slip out in wind. - **Remove for flowering crops.** Anything that needs bee pollination (squash, courgettes, beans, strawberries) must come out from under fleece once flowering starts. - **Wash and store.** Reusable for 3–5 seasons if folded and stored dry. Tears can be patched with garden tape.

For pest exclusion specifically, finer-mesh insect netting (the kind sold for carrot fly) is more durable than fleece and lasts a decade with care.

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Related terms

Cold frame

A cold frame is a low, glazed, unheated box that extends the growing season by trapping solar warmth around plants. It hardens off seedlings in spring, protects salads through autumn and winter, and overwinters borderline-hardy perennials.

Last frost

The last frost (or last spring frost) is the average date of the final freezing temperature of spring at your location. It is the anchor date for transplanting frost-tender crops — tomatoes, peppers, basil, beans, and squash — outdoors.

First frost

The first frost (or first fall frost) is the average date of the season's first freezing temperature in autumn. It ends the growing season for warm-weather crops and is the anchor date for planning final harvests, garlic planting, and cover-crop sowing.

Harden off

Hardening off is the 7–14 day process of gradually exposing indoor-raised seedlings to outdoor conditions — sun, wind, and cooler temperatures — before transplanting. Skipping it causes leaf scorch, transplant shock, stalled growth, or outright death.

Microclimate

A microclimate is a small area whose temperature, wind, humidity, or sun exposure differs noticeably from the surrounding regional climate. A south-facing brick wall, a frost pocket, or a sheltered courtyard can shift the effective hardiness zone by half a step or more.