Installing Row Covers: Simple Protection That Makes a Big Difference

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Row covers. Now this is one of those things that sounds boring but is actually incredibly useful. A row cover is basically just a layer of protective material — fleece, mesh, or plastic — placed over your crops to protect them from frost, pests, wind, or all three at once. Think of it like tucking your plants into bed. They’re warm, they’re safe, and nothing nasty can get at them while they sleep. Except it’s not sleep, it’s growing. But you get the idea.

I resisted using row covers for years because I thought they looked ugly. And they do, a bit. A garden covered in white fleece looks like a laundry explosion. But function beats form every time on my allotment now, because the results are undeniable. My carrots haven’t had carrot fly since I started using mesh covers. My early lettuce survives late frosts because of fleece. My brassicas go uncaterpillared (that’s a word now) because the netting keeps the butterflies off. It’s all about protection and it works.

JB uses row covers on everything and his crops are consistently better than everyone else’s. I thought he was just a naturally better gardener. Turns out he’s just a better protector. “Cover your crops, Tony” he kept saying, and I kept not listening. Now I listen. Now I cover. Now my crops are better. Sometimes the simplest advice is the best advice, you know what I mean?

Types of Row Cover

Horticultural fleece — the white, lightweight fabric you see everywhere. It lets light and rain through while raising the temperature underneath by 2-4 degrees. Brilliant for frost protection in spring and autumn, and for warming soil before planting. I buy it in big rolls — much cheaper per metre than buying pre-cut pieces. It comes in different weights — lighter stuff (17g/m²) for mild frost protection, heavier stuff (30g/m²) for harder frosts. I use the lighter stuff for most things.

Enviromesh — fine woven mesh that keeps out insects but lets in light, rain, and air. This is your anti-pest barrier. Covers the plants completely, pegged down at the edges, and nothing gets through. Carrot fly, cabbage white, flea beetle — all stopped in their tracks. More expensive than fleece but it lasts years if you look after it. I’ve had the same roll of enviromesh for four seasons and it’s still going strong.

Netting — comes in various mesh sizes. Fine mesh for insects, wider mesh for birds and pigeons. Make sure you get the right size for the job — bird netting with big holes won’t stop a butterfly, and insect mesh is overkill if you’re just trying to keep pigeons off your brassicas. I keep both types. Different jobs, different tools.

Clear polythene — creates a mini greenhouse effect. Great for warming soil and getting early crops going, but be careful in sunny weather because it can overheat and cook plants surprisingly fast. Always ventilate on warm days. I use polythene mainly for pre-warming beds in early spring.

Supporting Your Covers

You can just drape fleece directly over crops and peg it down at the edges — it’s light enough that it won’t damage most plants. But for mesh and netting, and for longer-term fleece protection, you’ll want some kind of support structure to hold the cover off the plants.

The cheapest and easiest option is hoops made from blue MDPE water pipe. You can get 25mm pipe from plumbers’ merchants for about a pound a metre. Cut it into lengths, bend them into hoops, and push the ends into the soil. The pipe is flexible enough to bend easily but rigid enough to hold its shape. Space hoops about a metre apart along the row and drape your cover over the top. Bob’s your uncle.

I cut my hoops to about 1.5 metres long, which gives a nice arch over a standard raised bed. You can buy fancy metal hoops or commercial tunnel cloche systems, but honestly, the blue pipe works just as well and costs a fraction of the price. Cheap as chips and effective. My two favourite words.

When to Use Row Covers

Spring — fleece over early sowings to protect from late frosts and warm the soil. This can bring your harvest forward by two to three weeks compared to unprotected crops. Mesh over carrots from the moment they’re sown to prevent carrot fly.

Summer — mesh over brassicas to prevent caterpillars. Mesh over carrots and onions to prevent root flies. Remove fleece once the frost risk has passed — plants need full sun and airflow in summer.

Autumn — fleece back on over late crops as temperatures drop. Protects salads, extends the season for tender crops, keeps the worst of the rain off brassica seedlings.

Winter — fleece over anything tender that’s overwintering. Double-layer fleece for hard frost nights. Mesh can come off most things over winter as the pest pressure drops (the insects are dormant). But keep netting on your brassicas because the pigeons don’t take winter off. Pigeons are a year-round menace.

Common Mistakes

Not ventilating under polythene covers — sunny days in spring can push temperatures under plastic to 30°C or more. Your plants will literally cook. Always prop open the ends or lift the covering on warm days.

Leaving covers on too long — plants under covers can get leggy and weak if they’re shaded by fleece for too long. Use the lightest weight that does the job, and remove covers when the threat has passed.

Not securing edges properly — if pests can get under the mesh at the bottom, the whole exercise is pointless. The cover needs to be sealed to the ground all the way around. I bury the edges in soil or weight them with bricks. No gaps. Zero tolerance. One gap and the carrot fly will find it. They’ve got a nose for it.

Using damaged covers — holes in mesh completely defeat the purpose. Check your covers at the start of each season and repair or replace any that are damaged. A small hole is all a butterfly needs to get through and lay eggs. And then you’ve got caterpillars in your enclosed space with no predators to control them. Ask me how I know. Don’t actually ask me. The memory still stings.

Storage and Care

Good covers aren’t cheap, so look after them. At the end of the season, wash mesh and netting with clean water, let them dry completely, fold them loosely, and store in a dry place. UV degrades most materials over time, so storing them out of direct sunlight extends their life. Fleece is harder to reuse — it tends to tear and degrade faster — but the heavier weights can last a couple of seasons if you’re careful.

Label your covers when you store them. Trust me. Come March you’ll be standing in the shed with three similar-looking rolls of white fabric going “which one is the fleece and which one is the mesh?” They look the same when folded up. Ask Ronny. He had a beautiful crop of carrots protected by fleece instead of mesh. Kept them warm from frost but didn’t stop a single carrot fly. He was not amused.

Look after yourselves. Take good care. 🌱