The best way to Overwinter Potted Perennials From a Greenhouse
Throughout the winter, the chilly weather may make the interior of a greenhouse too cold to get a few plants. If you plan in advance, you’re able to successfully carry these plants through the winter and to the spring, once you’re able to move them back to the greenhouse. A sunken cold frame is smaller than the usual greenhouse, so that it heats quicker and the insulating material of the surrounding soil helps it to retain heat. These can home your potted perennials during cold spells when you don’t want to carry your plants in your property. The U.S. Department of Agriculture plant hardiness zone for containers is two higher than it is if you planted the plants at the ground. Take this into consideration when overwintering them. Should you potted perennials are not sturdy enough for your growing zone, then you have to slip them into dormancy by bringing them into a cool, dark place over the winter.
For Actively Growing Plants
Dig a rectangular hole in the ground deeper than the height of your tallest potted plant and broad enough to get all of your plants to fit, plus room for cinder blocks on all sides. Make the southern side of this hole shallower than the northern side so you’re able to slope the plastic panel to catch the sun’s rays in the south.
Line the hole with cinder blocks to keep the sides from collapsing in.
Set the potted perennials inside the hole.
Insert a thermometer on the side of the hole to measure the air temperature at the cold frame.
Cover the surface with a clear plastic panel to trap the sunlight’s heat and heat. Mound dirt the sides up to cover any gaps which could let in cold air.
Prop open one side of this plastic panel with bricks during warm winter days or in the event the temperature in the cold frame gets above 70 degrees Fahrenheit.
Non-Hardy Plants
Reduce feeding and watering in autumn to slow the plants’ growth.
Bring the potted plants in the ground to an unheated basement or garage where the temperature remains near freezing without going below 32 F.
Water just to barely keep soil moisture over the winter to maintain the plants dormant.
Return the plants to the ocean when temperatures warm in the greenhouse to spring growing temperatures.