December 29, 1998
Winter roared into many of our gardens about a week ago. At my home the temperature got as low as 11F (-12C), which is colder than it's been in several years. Now that the weather has returned to a more typical mild dampness, it seems like a good time to take stock of how the various vegetable species handled the cold snap. We'll also touch on the methods I use for protecting these valuable winter crops.
The first thing I noted was the winter stalwarts - kale, leeks and Brussels sprouts. I have yet to see the weather get the best of these plants. In my garden they are not given any protection from cold temperatures or from rain, yet they are still dependable sources of fresh food during the cold season.
I also left two beds of brassicas unprotected. The fall broccoli is pretty much toast, but I expected that. Actually I was pleased with how late it hung on this fall; probably this was due to the extended nice weather we experienced. The overwintered broccoli and cauliflower, though, handled the extended freeze just fine. That wasn't too big of a surprise - in past winters it's been soggy soil that's done them in, never the cold.
Overall I was pleased with how the crops inside the PVC hoophouse did. When I first heard the cold snap was coming, I decided to see how well a floating row cover (Agro-fabric P17) would work as extra insulation for the plants. It seemed to me it might have advantages over a leaf or straw mulch. Over most things I layed a double layer, but put a quadruple layer over the celery since I wasn't sure about that crop's hardiness. Unfortunately, the cold blew in hard from the east, which is not the normal direction for strong winds in my garden. The hoophouse, which runs east-west, did not provide any real protection. Much of the row cover blew off, although it stayed in place over the celery. So most plants ended up being exposed to a temperature of 20F (-7C). When the wind finally died down, I put my hoophouse back together and re-covered everything with the row cover fabric.
The celery still looks great. This surprised me, since I'd heard from several sources that it was only half-hardy. Apparently the P17 fabric provided a good insulating layer. Also unfazed by the cold were kohlrabi, claytonia (miner's lettuce), overwintered onions and scallions, carrots, parsnips (which were not protected by a row cover), escarole, radicchio, spinach, and garden cress.
There were no total casualties, but a couple species were somewhat damaged. It was no surprise that the lettuce showed some damage - what pleased me was that it survived at all! I knew it was hardy to the low 20s (F); apparently 20F-21F is the cutoff if it has no extra protection. I was disappointed, however, that the minutina didn't hold up better. It has been advertised as a very hardy salad green, but it fared only about as well as the lettuce did - where the row cover did not protect it, the leaves were pretty heavily damaged by the cold.
You may notice that a couple of items are missing from this list. Beets were an early casualty - early August to be exact. Some slugs came along and pruned them for me. Normally I also grow corn salad (mache) for winter, but didn't this year. However, based on previous years' experience I'm confident it would have weathered this cold snap well.
If you don't already have a winter garden, obviously it is too late to start this year! But we do have some resources available on our site, which should help you in your future planning.
How to Make a Cloche - For many people, a cloche is their method of choice to protect winter plants. They are cheap to build and go up fast. Also they handle winter windstorms better than a PVC hoophouse, due to their lower profile. But they don't protect YOU from the weather (so you get soaked when harvesting in a rainstorm), and humidity can be a problem with some of the more vulnerable crops.
How to Build a PVC Hoophouse - I really am sold on using this in the winter, even though I sometimes have to spend 10-15 minutes repairing it after a strong windstorm. I find it much more pleasant to harvest out of the weather. Also, the air circulation around the plants is better than with a cloche. On the other hand, a hoophouse doesn't give you quite the temperature protection that a cloche does. Since our main problem in winter is with rain and dampness, though, I don't find this to be a significant drawback.
Winter Vegetable Gardening - On this page I discuss more of the vegetables that can be grown in the winter garden. Also there's a table which tells you when they need to be started, and how cold a temperature they can probably handle.
All contents © Travis Saling
This page was last updated July 9, 2011