Cold Hoops Mid Winter Update - More Insights from The Poly Low Tunnel Experiment

Now that the weather has dropped significantly and then warmed up I went out to check on the cold hoop crops and see how they were affected. For background info you can read my previous post on the cold hoop experiment here.

It finally got down to -5 F or thereabouts a couple nights in a row, then it got back up in the teens and twenties and hung around there. Now we've been back to 20s lows and above freezing in the day for a few days.

I figured the colder weather and the freeze/thaw action could have an effect on our winter crops. First of all let me show you what things looked like just before that cold snap when the lows were generally in the low teens.

The hoops have been holding up quite nicely.

Peeking inside I can see the bok choy is doing well since my last thinning. It is a little light in color and showing the slightest sign of limpness, possibly due to the weather cooling down more lately.

Carrots look solid and look there's a worm!! By the way the ground is still not frozen in here while it has been frozen everywhere else outside the hoops for weeks!

Spinach looks fantastic! And it tastes so buttery and sweet.. I've never had spinach so good as in this cold weather.

Likewise the cilantro is looking great! I didn't know before this fall that cilantro actually thrives in cold weather! I always thought it was a warm weather plant and had trouble keeping it from bolting (not that that's a problem because I like coriander seeds). Turns out it thrives in cold weather, and the flavor during the winter is so different... it's very sweet and mild!

And the onions are very hardy and tasty.

Now onto the more recent update.

Now the following is after the more extreme lows down to -5F and then back up into the mid-high thirties for some of the warmer days.

The hoops look great!

The snow is building up on the sides which should be helping insulate the inside temperature and prevent cold air flow from coming in. The hoops seem to be holding up well to this amount of snow, but I am shaking it off to allow in more sunlight and to prepare them for more snowfall that we are expecting.

There are a few hoops that are spaced farther apart and are sagging slightly more from the snow but, in general it's in great shape. It seems 3-4 feet is a good max spacing of the hoops for this size tunnel if you expect a lot of snow.

Wow look at those ice crystals!

So inside the hoops the bad news is that the bok choy is pretty wilted. The good news is that I have a pretty good gauge of how far I can take them into the winter without extra protection like deep mulch or an inner hoop or cold frame.

The other good news is that while most of the leaves are wilted from extreme cold and then thaw, some of the smaller inner leaves still look perky and more or less undamaged. So this gives me a clue that the plants may still be alive and if that is the case and they continue surviving... come spring their established root systems would help them generate new leaves rapidly and we would have bok choy much much earlier than if we started them indoors and transplanted.

Right now I'm giving them about a 50/50 for survival.. we'll see!

The spinach on the other hand looks to be doing much better. Some of the bigger outer leaves look a little limp and probably have some frost damage, but not nearly as bad as the bok choy. Most of the leaves look happy, healthy and they are quite crisp and dark green. It's looking like they are surviving quite well!

The carrots, cilantro, beets and onions all look perky and unscathed by the cold so far! I think we're going to see some vigorous growth coming out of these plants early spring.

The biggest takeaways for me so far are

• How far I can take these plants into the winter
• Which plants can handle lower lows
• The ground still isn't frozen inside the hoops!
• How about that worm huh?
• Walking down these low tunnels requires a lot of squatting and some cold water running down my neck :)