You’ve got a nice bunch of pretty little green stems poking up from your seed starting containers (If you missed it, read how to start your own seeds here), but now what? How do you transition them from the comfy indoor life to the harsher outdoor weather to get them ready for the spring planting? You make a cold frame of course.
A cold frame is used to gradually get your plants used to the outdoor weather. You can buy commercial cold frames, but they’re extremely easy to make yourself and very cost effective. You will need something clear for the top to allow light to get in. This could be some old windows, sheets of Plexiglas, or even just a roll of clear plastic. For the sides you can use anything from straw bales to cinder blocks, or if you want to get really fancy, you can build your sides from wood and attach the top with hinges for easy access.
In its simplest form, you build a cold frame by making a square or rectangle with your straw bales or cinder blocks (if you use cinder blocks, be sure the holes are facing upward, not sideways, or air will blow into your cold frame). Then you just lay your windows or plastic over the top opening, making sure the entire opening is covered. The best cold frames have higher back walls and lower front walls, and face a southward angle to allow plenty of warm sun to shine through the top windows or plastic. Basically what you have is a miniature greenhouse.
Keep your trays of seedlings in the cold frame while the sun is shining and bring them inside at night. This will help “harden off” the plants and get them used to outdoor temperatures. The sunshine also prevents the plants from getting too long and leggy, allowing them instead to grow thicker, sturdier stems. Once the temperatures get a bit warmer, you can leave your plants in the cold frame all the time, until you are ready to transplant them (We’ll be discussing that next post). If the temperatures get very warm in the day, be sure to open the top of the cold frame or you run the risk of cooking your plants.
As a final note, a cold frame doesn’t have to be used just during the spring. You can easily set one up in the fall to extend your autumn growing season into the early winter months as well.
Copyright © Amber Reifsteck ~ The Woodland ElfEnjoy this post? Click here to subscribe by email and get new posts delivered to your inbox.