Master Gardener: Extending the vegetable growing season at Seed to Supper Farm

My answer is a definite … OK, it’s impossible to give a definite answer because we never know what the weather is going to do.

However, gardeners are gamblers. I mean, you have to be a little bit of a gambler to put a tiny little seed in the ground and expect it not only to grow but also to produce something you can eat.

At our Seed to Supper Farm in Bixby, where we grow vegetables to donate to area food pantries, we are gambling like we’ve never gambled before. Just last week, we were still planting seeds hoping for a good harvest. However, we’re planting seeds based on days to harvest and which crops can handle a little dip below freezing here and there. So, here’s what we are doing.

The event that typically ends the vegetable growing season for most vegetables is the first freeze. In our area, the average first freeze date is Nov. 15. So, if this is an average year, we should have a decent growing season up until that date. However, if you remember, last fall we had our first freeze in mid-October.

In the case of a light freeze, you can cover your crops with a layer or two of garden cloth during the cold snap to help extend the growing season. For us, since we have about 15 100-foot rows, we probably won’t be doing that. When the deep freeze arrives, we are done for the season. So, at this point, we are rolling the dice and gambling on the weather.

Three weeks ago, we planted beets and turnips. Both of these have a days-to-harvest of about 60 days. If we do the math … We planted around the first of September, so if this is a normal year, we should get a good harvest. And if the first freeze is delayed, we’ll get an even better harvest.

About a week after we planted beets and turnips, we planted cabbage. This particular variety of cabbage is supposed to produce a crop in 50-60 days, so again, we should be in pretty good shape in an average temperature year. However, one of the good things about cabbage is that it can handle temperatures down to about 20 degrees without significant damage. With any luck, we won’t experience those temps before Dec. 1.

Next up, we planted kale and collards. Once again, both of these have a days-to-harvest of about 60 days, which will put us pretty close to the Nov. 15 average freeze date. But these plants should also be good down to about 20 degrees, so we should be good… emphasis on the “should.”

We also planted some radishes, but radishes have a pretty short days-to-harvest of 20 to 40 days, so we should be able to plant radishes up until the beginning of October.

As a home gardener, you have a few options to help you extend the growing season. First would be row covers.

Row covers are a fairly economical way to help extend your garden season. In reality, they are just what they sound like: a fabric that covers your crops. Row cover fabric or frost cloth is available in a variety of sizes and densities. This fabric is suspended over your crops using some kind of support mechanism. Typically, these supports are in the shape of a half circle that rises above your crop that holds the fabric above your crop. Lightweight row cover fabric can give you about 2 degrees of protection. With some of the heavier fabrics, you can get 6 to even 10 degrees of frost protection. Basically, they are a way to get you past an early dip in the temps or through an unseasonably early freeze. Two degrees doesn’t sound like much protection, but in some cases, that could be the difference between your crop freezing or living to grow another day.

Cold frames are a more permanent way to extend your garden season both in the spring and in the fall. In the spring, they are a good way to get a jump on the garden season, and in the fall, they are a good way to keep some crops going after experiencing freezing temperatures.

There are a variety of ways to approach building your cold frame, but for the most part, they are rectangular boxes with a clear roof that is hinged so you can prop it open on warmer days. Cold frames should be located east to west horizontally with the top opening toward the south. This allows for maximum heat absorption.

Cold frames are typically constructed out of wood, but do not use wood that has been treated with creosote or pentachlorophenol because fumes from these products will accumulate in your cold frame and potentially harm your plants. It’s also a good idea to have the structure be higher in the back than in the front. This will allow for maximum sun exposure and good drainage.

The clear roof can be plastic or glass. If you are crafty, visit a few garage sales to see if you can find an old window frame since these would make a great top for your cold frame. Weather stripping under the lid wouldn’t be a bad idea, either.

Treat your plants in the cold frame just like you would your other plants. They’ll need to be watered regularly, and on warmer days, you’ll probably need to lift the lid to provide ventilation to prevent them from getting too hot.

Here’s hoping those freezing temperatures arrive late this year! See you in the garden!

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