Just-planted transplants and newly germinated seedlings can be damaged beyond recovery by a sudden hot, sunny spell, especially if drying winds come along with the heat. To protect such vulnerable young plants, it's wise to set up temporary screens; these should be left in place until the weather cools at least slightly or until the plants have had time to develop strong root systems that can efficiently absorb water from the soil.
To shield a few plants from sun and wind, insert shingles or pieces of plywood about 6 inches wide and a foot tall in the ground on the sunny side of each plant. For larger plants, make a screen by draping burlap or shade cloth over a cylinder of 3/4-inch mesh wire or by stapling either material to stakes set firmly in the ground.
Also known as shade fabric, this woven material is useful as a temporary or long-term screen against hot sun and drying winds. Made of UV stabilized polypropylene, it's available at many nurseries and through mail-order firms. For most vegetable crops, use 30% shade cloth, which lets more sun through; for shade lovers, use 47% or 63% shade cloth.
You can drape the cloth over a bed of plants, supporting it on stakes as shown at left, or fasten it to hoops to protect rows of crops. It's also useful for covering the roof and sides of larger, permanent structures built especially for growing shade-loving plants.
Making a Portable Plant Screen
A portable plant screen does a good job of shading a bed of seedlings or transplants. Prefabricated lattice, sold at home improvement stores in panels of various sizes, makes a quick and easy screen; you can use the panel whole or cut it to fit the garden bed. Drive in 1- to 1-1/2-foot-long 2 by 2 stakes at the corners of the bed and at the midpoint of each side. Set horizontal slats made of 1 by 2 lumber on top of the stakes; then rest the lattice on top of the slats. You can also prop up a lattice panel on the south side of a planting bed, where it will provide both shade and protection from wind.