Season Extension with Row Cover

What is row cover and what does it do?

Row cover is a lightweight spun fabric draped over plants, either directly on them or over hoops. It traps a little heat, blocks wind and can keep many insects off crops. Different weights give different levels of protection.

Lighter fabric gives more light and less frost protection, and heavier fabric protects more but lets in less light. Read the product description and ask your extension office what weight suits your use.

Know the fabric choices. Lightweight cover is mostly for insects and a degree or two of frost protection, medium weights suit early spring and fall nights, and heavy cover is for deeper cold. Match the weight to the job and ask your extension office what suits your crops.

• Light fabric: insects and mild frost
• Medium: early spring and fall
• Heavy: deeper cold, less light
• Always read the product label

What are the main uses?

Use it in early spring to protect transplants from light frost and to warm soil, in fall to extend harvests, and during the season to exclude insects such as flea beetles and cabbage worms.

It does not replace a heated greenhouse. It adds a few degrees in cold nights and has limits in a hard freeze.

Hoops make the whole system easier. Wire or flexible conduit hoops set over a bed hold the fabric up, let plants grow beneath it and keep leaves from freezing against the cover. Set them before planting so you do not disturb roots later.

• Spring frost protection
• Fall harvest extension
• Insect exclusion
• Wind protection for seedlings

How do I install it?

Prepare the bed, plant and water, then lay fabric over plants with loose slack so they can grow. Anchor edges thoroughly with soil, boards or weights so wind cannot lift them. Hoops made of flexible tubing or wire hold the fabric off plants and prevent damage. Water the bed before covering, since moist soil holds and releases more warmth overnight than dry soil does, and cover late in the afternoon so stored heat is trapped.

Seal gaps when excluding insects, since a small opening lets them in. Keep fabric away from sharp edges and handle it gently so it lasts.

Bring thermometers. A small min-max thermometer under the cover tells you whether your system is doing its job, and it takes the guesswork out of when to vent and when to close up.

When should I vent or remove it?

Covered plants can overheat on warm, sunny days. Open or lift edges on mild days and close up before the temperature drops. Check weather forecasts for sudden warm spells.

Remove cover from crops that need pollination, such as squash, cucumbers and peppers, once they flower. Remove it from any crop when summer heat arrives, unless it is shade fabric made for that use.

Keep clips, rocks or soil handy to hold edges, and expect to adjust after storms. Fabric that flaps in the wind wears out fast, so secure it well and check it after every blow.

Does it cause problems?

Moisture trapped beneath can encourage disease, and pests that were already under cover can multiply. Check under fabric often. Slugs may hide in damp conditions.

Rotation and clean beds matter, since pests trapped under the fabric cannot be hunted by predators. Look for damage and open covers if you see problems.

Count the cost categories: fabric, hoops, anchors, and a little time each season. Fabric is reusable, which spreads the cost over several seasons, and homemade hoops can be inexpensive.

How do I care for and store row cover?

Shake off dirt, let fabric dry fully, fold loosely and store in a dry, rodent-proof place. Sunlight breaks down fabric over time, so storing out of light extends its use.

Patch small tears with tape made for the purpose and replace worn sections. With care, many gardeners reuse row cover for several seasons, which lowers the cost per season.

How does row cover fit into a larger plan?

It works with other methods such as mulch, cold frames, low tunnels and good timing. Start with cheap protection and consider larger structures once you know what you grow and sell or eat.

Keep records of dates, temperatures and results. Ask your extension office or local growers about what works in your climate, and check current guidance from groups such as SARE and Cornell Small Farms Program.

Last reviewed: November 12, 2026. Written by the Homestead & Small Farm Editorial Team. See our editorial policy.