For centuries, gardeners have been looking for ways to extend the harvest season in autumn and to get a jump on spring. Bell-jar cloches were the first season-extending accessory widely used by gardeners. They are large bell-shaped jars placed over small plants. Modern technology has brought gardeners non-woven lightweight fabric row covers. They are so light they can be put on top of plants without weighing them down or damaging them. The lightest-weight-fabric row covers can be used season-long because they don’t hold in the heat, which could cook the plants. Medium-weight row covers are best used in spring or fall because their heavier weight holds in heat to protect plants from frost.
Traditional Glass or Plastic Individual Cloches
Put the cloche over transplants set out in early spring to get a jump on the growing season. It can quickly get hot enough to cook your tender young plants. Remove the cloche if temperatures rise above 45 degrees F when skies are sunny.
Use a cloche to warm up the soil in early spring. You’ll be able to plant seeds earlier and to set out warm-weather transplants earlier. Set the cloche over the area of the garden where you want to plant seeds or transplants about seven to 10 days before planting.
Set cloches over plants to protect them from frost at season’s end. Many warm-weather plants will continue to produce during the warm daytime temperatures of fall if they are covered when nighttime temperatures drop below freezing. Remove cloches during the day so the plants don’t cook in the warm daytime temperatures of fall. This is extremely important in fall because the ground is warm from the summer heat and the interior of the cloche will heat up much faster in fall than in spring when the ground still has a winter chill.
Modern Fabric Row Cover Cloches
Use fabric row-cover cloches to cover an entire row of plants from cool or freezing spring temperatures. Use medium-weight fabric row covers for this application because they hold in a small amount of warmth. Secure the edges of the row cover with plastic or metal pins inserted into the ground, or hold the edges down with rocks.
Use fabric row covers to protect tender crops from freezing temperatures in fall. Lay the row covers right on top of the plants; they are made of lightweight non-woven fabric and do not weigh down the plants. Medium-weight row covers help hold in warmth, especially in fall when the ground still has residual heat from summer.
Put lightweight fabric row covers over plants during the growing season to protect them from insect pests. Squash bugs will not be able to attack squash vines, carrot flies will be unable to get to carrots. For this application, you must seal the bottom of the fabric to the ground. Bury the edges with soil completely so the insects can’t find their way in. Be sure to remove the row covers when the blossoms form so beneficial insects can pollinate them.