2/20/17 Update: I didn’t get any greens over the winter, but it looks like I’ll get plenty of spinach and lettuce a head of everyone else, and my rosemary bush survived. Not bad for the first try.
Update: This is the garden and pod after 24 hours of 10 – 14 degreed F weather in mid-December 2016.
Surprisingly, the broccoli (and some weeds) survived with no water buffer. The blue-green plastic I put on the plants are Wall o’ Waters, empty of water. I figured two layers of heavy plastic couldn’t hurt!
The two pods with Wall o’ Water covering and without are shown below. The rosemary, choi and spinach did very well. The lettuce survived, but not very well and I doubt it will turn out to be productive before January kills it. It looks like the rosemary may survive all winter.
Last Tuesday, 12/6, I harvested the last of the greens from the garden, finding a nice batch of chard, spinach and even a little kale under frost-wilted outer leaves. But I knew the end was near with several days well below freezing predicted. Below is a picture of the final harvest before I opened up the garden and let the chickens in.
By yesterday, 12/11, the chickens had stripped out all of the frost wilted greens, the clover cover crop, and even a lone (and thorny) artichoke that decided to finally grow far to late for me to get any benefit of it. You’ll note the plastic “pods”: the big ones are about 2′ x2′ x 3′. The lone blue pod is where I put a dahlia bulb in a deep hole — the highest point of the bulb is about 18″ deep — and then covered it with hay and then the blue half barrel shown. I hope the bulb will be sound when I dig it up in the spring: that is the experiment.
The last few nights the temperature had dropped down to the low 20s, so I added buckets of water to fend off freezing temperatures. Since freezing water is exothermic (gives off heat) the temperature inside the pods should stay at the freezing point (but no lower) until all of the water in the five gallon buckets has frozen — though obviously the plants further from the bucket will be colder. As you can see below, so far so good.
The plot on the left is: rosemary, toy choi, spinach and lettuce. The plot on the right is the same, minus the rosemary, and plus some volunteer garlic. The difference is, the lettuce on the left was transplanted, and the spinach on the right was transplanted. (All of the toy choi was transplanted.) Next year I’ll have to specifically plant little 2′ x 3′ plots with the pods in mind, since transplanting really knocked back the growth.
Thursday night is supposed to drop down to the low teens, and stay there for over 24 hours! I’d hoped my mini-greenhouse-pods would last at least through December, but the plants may not make it through this atypically cold onslaught. I plan to add a layer of plastic over them and the buckets — and to gather enough greens for a salad on Wednesday night, just in case.
Below is what’s inside the smallest pod (a cracked storage container that worked as an excellent cold frame this spring): broccoli. I don’t see any way this is going to survive the extreme cold on the way.