Seedlings are tender little things, easily damaged by the elements and easily killed by pests. Transplants you purchased from a nursery should be hardened off and ready for outdoor conditions, but conditions in your garden might be more extreme than the nursery from which you bought them.
Harden off seedling you raised indoors before planting them in the ground. Plant them in the ground when the nighttime temperatures are warm enough for the type of plant. See Early, Midseason, and Late Vegetables for a list of vegetable hardiness.
If you are “pushing” the season by planting early, or the weather turns unseasonably cold soon after you set your plants out, there are several methods for protecting the transplants from harsh weather. In addition to the simple methods listed below, also see Row Covers and Cold Frames and Hotbeds.
Shade the Transplants
- Set a board on a couple of bricks, concrete blocks or vegetable crates to shade the row.
- Shade individual plants by sticking a shingle (available from lumber yards) in the ground on the south side of each.
- Throw a handful of straw on the transplants—not enough to smother them, but enough to break the force of the sun.
Protect Transplants from the Wind
- Prop up a wide board or stick a shingle on the windward side.
- Use a hoe to pull the soil toward the wind, making a trench about 4 inches deep with a mound of soil on the windward side. Plant in the bottom of the trench.
- Pile branches on the windward side of the transplants.
Protect Transplants from the Cold
The best way to protect transplants from an unexpected cold snap is to cover them. Covers protect plants by using the heat stored in the earth. To understand how this works, see Protecting Plants From the Cold. If you don’t have row covers set up, throw an old blanket or sheet over the plants, pile straw on them, or prop a board on some bricks or boxes as described above. Leave the cover in place for a few hours in the morning to let the plant warm up slowly.