A friend/neighbor is DIY exemplar and always looking for a project around his home or otherwise. When asked, he was happy to build a few cold frames for me. Yay! Two designs; each is in consideration of the sun’s track and solar gain.


Why a cold frame; and what is a cold frame? The why is in order to extend the growing season where it is usually short; doing so on both the Spring and the Autumn ends of the season. These frames are not attached to, but are resting upon the existing bed. When night temperatures are warm enough, these cold frames will be removed and put in the shed.
What is a cold frame? Originally, they were made with an old window as the top, hinged for opening during the day/closing for late afternoon and evening as temperatures dive, and often made from scrap wood. A stick or block of wood is used to partially open the top during the day. The temperatures within a cold frame generally exceed the ambient outdoor temperatures, especially in zones of strong sunshine/solar gain, like here in Colorado and at altitude. Therefore, it is vital to vent or open the cold frame according to your specific conditions and the variations of weather daily.
Are they worth that little bit of responsible monitoring? Absolutely! If one wants fresh greens a month or more before the ground can produce them or wants to have fresh picked greens into Thanksgiving or beyond, YES, a cold frame.
Soil temperature is how seeds know when to germinate. Sunlight is how they grow (photosynthesis); but, without warm enough soil, per the requirements of the particular seed/plant, the seed can’t and won’t sprout. That displays the intelligence of plant life.
And, a surprise; to me, anyway. Chard babies are sprouting in one seed snail! Four of them.




