Cold Frames and Row Covers: Extending Your Growing Season on a Budget

What Each Tool Actually Does

Both cold frames and row covers create a slightly warmer microclimate around your plants, but the mechanisms and degree of protection differ considerably.

A cold frame is essentially a bottomless box — typically wood or rigid foam — topped with a transparent lid, often an old storm window or polycarbonate panel. It traps solar heat during the day and slows heat loss overnight, creating a stable environment that can stay 5–10°F warmer than the outside air, sometimes more on sunny days. Because the frame is rigid and enclosed, it also shields plants from wind and heavy rain.

A row cover (also called floating row cover or garden fabric) is a lightweight spun-bonded polypropylene fabric draped over plants or supported by wire hoops. It lets in light and moisture while trapping a thin layer of warmth. Depending on the fabric weight, row covers can protect against a few degrees of frost. The lightest grades are primarily used to block insects rather than cold.

If you're weighing whether either of these tools fits into a larger garden setup, see our garden layout planning guide for how to organize your beds around seasonal protection zones.

Side-by-Side Comparison

Here's how the two approaches stack up across the criteria that matter most to home gardeners.

One practical note: cold frames and row covers aren't mutually exclusive. Many gardeners use row covers for spring and fall frosts, then transition to cold frames for deep-winter crops like kale, spinach, and mâche.

Cost and DIY Options

Row covers are among the most affordable season-extension tools available. A roll of lightweight fabric wide enough for a standard 4-foot bed costs roughly $15–$40 depending on length and weight. Wire hoops to support it add a few dollars more. The fabric typically lasts 2–4 seasons with care.

Cold frames have a wider cost range. Purchased kits can run $60–$200 or more, but a DIY version built from salvaged lumber and an old storm window can cost under $20 — sometimes less if you're resourceful. Rigid foam insulation board is another cheap option for the sides. The lid is usually the key variable: glass transmits more light but breaks; twin-wall polycarbonate is lighter and more durable but costs more.

For gardeners already doing container or small-space growing, cold frames pair naturally with that approach — see our container gardening guide for ideas on combining portable pots with seasonal protection.

What to Watch Out For

Neither tool is entirely hands-off.

Cold frames need venting on warm, sunny days. Temperatures inside can spike rapidly — even in early spring, a closed cold frame on a sunny afternoon can exceed 80°F, stressing or killing cool-season crops. Most gardeners prop the lid open during the day and close it at night. Automated vent openers (available for $20–$40) can help if you're not home during the day.

Row covers need to be secured at the edges so wind doesn't dislodge them. Rocks, sandbags, soil staples, or wooden boards all work. If you're using them for pest exclusion, they need to go on before pests arrive — draping fabric over an already-infested bed won't solve the problem.

If you're considering a more permanent or larger-scale structure, compare how these tools measure up against bigger investments in our greenhouse vs. grow tent comparison.