How to Make a Humidity Chamber for Plants

Slip wooden dowels in the soil on each corner of your planter. The dowels need to be tall enough so that when secured into the soil, they extend several inches above the seedlings. Place additional dowels every eight to 12 inches along the sides of the planter. The dowels hold the plastic off the plants and soil and give shape to your humidity chamber.

Secure plastic sheeting to one side of your planters. If the planters are made of wood, you can use a staple gun. If the planter is plastic or some other material, use duct tape.

Unroll the plastic sheeting over the top of the wooden dowels, and secure it to the opposite side of the planter. When complete, your planter should have a horseshoe-shaped span of plastic over the top.

Close off one end of the humidity chamber. Cut a piece of plastic sheeting, and tape its top to the existing plastic sheeting and its bottom to the planter.

Create an opening for ventilation. On the final side, tape plastic sheeting to the top of the existing plastic chamber, but leave the bottom unsecured. You can prop this plastic open or leave it lying closed to adjust the humidity level as needed.

Water your seedlings. Once you water the seedlings, the humidity chamber will trap the moisture inside, creating the warm, moist environment that will help your seedlings thrive.