It’s been a couple of weeks since my last update on cold frame #1 (CF1). I have romaine lettuce, spinach and radishes growing here. As you can see by the picture of a spinach plant, the plants are getting a little bigger. Growth is not as fast as in the summer obviously, but in view of the below normal temperatures we have had lately (daily temps in the 50’s and nightly in the 20’s) here in southwest Missouri, I am happy they are surviving at all. For added protection, I have made sure to place covers over the frames and even have rigged up two 40 watt light sources to help keep the internal temps in the high 40’s even when it has gotten as low as 24F.
Slow Growth Dynamics
The cooler growing environment is resulting in slower growth. That’s a given. What interests me, however, is the overall effect slow growth will have on the morphology of the mature plants. I do know that in very warm conditions, plants like lettuce and spinach will have a tendency to bolt. (Bolting is very common in plants like these when they begin to form flowers and seeds in response to stresses like too much drought, light and heat). In order to avoid this problem, I am making sure to give my plants about an inch of water per week, light in the late fall and winter is not very harsh and they are definitely not getting over heated. Even under full sun, with the lids closed, I am lucky to see internal temps in the mid 60’s. So when can I expect my first harvest? Perhaps sometime in late December. I plan to do periodic updates as time goes along. CF2 currently only has about five young spinach starts in it and will be getting additional romaine and lettuce starts that are now being hardened off.