There's a surprise frost forecast — what should I cover and with what?
Cover warm-season transplants and seedlings with row cover fabric or old bedsheets — not clear plastic sheeting directly on leaves — and place covers before sundown to trap daytime heat.
The most important cover material is spun-bonded row cover fabric (sold under brand names like Reemay or Agribon). It lets light through, traps radiant heat from the soil, and provides 4–6°F of frost protection at the lightest weights and up to 8–10°F at heavier weights. Old bedsheets, burlap, and newspaper work nearly as well for overnight protection. These breathable materials can rest directly on plant foliage without damage.
Clear plastic sheeting should not be placed directly on plant foliage. Plastic doesn't breathe, traps moisture against the leaves, and can cause freeze damage to whatever it directly contacts when temperatures drop. If you use plastic, support it on hoops or stakes so it creates a tent above the plants, not a wrap around them.
Place covers before sundown. Covering plants at 10 PM after temperatures have already dropped traps cold air under the cover along with the plants. Covering while temperatures are still above freezing traps the day's accumulated warmth in the soil and air beneath — that heat continues to radiate through the night and keeps temperatures under the cover noticeably warmer than the open air outside.
Cold-season crops — kale, spinach, lettuce, peas, carrots, brassicas — typically don't need covering for a light frost (28–32°F). Established plants of these species can often handle temperatures in the mid-20s°F, especially if they've had any exposure to cool weather to harden them. Save your covers for tomatoes, peppers, cucumbers, basil, and other warm-season plants that are damaged at 32°F.
- TomatoThe warm-season anchor of the summer garden.
- PepperA tropical perennial grown as an annual — patient, slow, and particular about warmth.
- BasilThe summer companion — to tomatoes, to pasta, and to the gardener with a south-facing window.
- CucumberA thirsty vine that wants warm soil, steady water, and something to climb.
- ZucchiniThe summer squash that turns a garden into a produce stand — if you can keep the vine borers away.
- AphidSoft, clustered insects on new growth causing curled leaves and sticky honeydew.
- Bird DamageBerries pecked or missing, seeds scratched from beds, and seedlings dislodged — birds feeding on ripe fruit, seeds, or soil grubs.
- Cabbage MaggotBrassica transplants wilting and dying as white maggots tunnel through roots at or below the soil line.
- Imported CabbagewormRagged holes in brassica leaves with pale green caterpillars and green frass nearby.
- Cucumber BeetleYellow-green beetles chewing cucurbit leaves and flowers; rapid wilting may signal bacterial wilt transmission.
- What is a last frost date and how do I actually use it?Your last frost date is the average date of the final freezing night in spring — it's a probability, not a guarantee, and smart planting adds a buffer of 1–2 weeks beyond it for cold-sensitive crops.
- How can I extend my growing season in fall?Row cover fabric, cold frames, and switching to cold-hardy crops are the three most reliable tools for extending production 4–6 weeks past your first fall frost.
- How do I harden off seedlings before transplanting?Gradually expose indoor seedlings to outdoor conditions over 7–10 days, starting with an hour of shade and building up to full sun and overnight temperatures before planting.