We know, it’s going to cool down eventually, right? We might even have a winter at some point. For vegetable gardeners, winter is either a time to rest, a time to plan for next year, or a time to lament that we aren’t outside growing stuff anymore. Honestly, for me, winter is a bit of all three of those things. Yes, I miss growing and harvesting vegetables, but I also appreciate a little break. And in those times when I am missing growing vegetables, I tend to make plans for the next growing season. But did you know that with a little preparation, you can continue to grow vegetables as we enter into winter…maybe most of the winter if you prepare for it.

Yes, a greenhouse would be wonderful, but not all of us are in a position to invest the funds necessary to build a greenhouse in our backyard or even have the space to erect a greenhouse if we could afford it. So, how do we continue to grow vegetables during the colder months? We have a couple of options.

First of we can invest in what is called a high tunnel. High tunnels are typically constructed out of U-shaped metal tubes and a clear plastic sheeting covering. They are called high tunnels because they are tall enough for you to walk in them. There is also an option called a low tunnel. Low tunnels are just tall enough to cover your plants. You would need to remove the covering to get at them. But some of us don’t even have room for a high or a low tunnel. For us, there’s something called a cold frame.

There are a lot of ways to build a cold frame that don’t require a large financial commitment. The photo shows a cold frame made of wood with a plexiglass lid but there are a lot of variations on this theme. For example, imagine getting several straw bales, placing them in a U shape and then using some clear plastic as a cover, maybe held down with bricks. Maybe the plastic would even be at an angle to increase sun exposure. Either way, there are a lot of ways to construct your own cold frame that don’t take a huge investment.

You’ll want your cold frame to run east and west with the clear plastic covering facing the south. This will place you cold frame in the best position to absorb heat. And yes, it will need good sun exposure.

One of the great things about cold frames is that the temperature inside is usually between 5 and 10 degrees warmer that it is outside which means you can continue to grow in them until the outside temperatures really get cold. And sometimes, all you need to keep going when it does get colder is to cover them with something thicker during the night and then take that extra cover off during the day. During the day, the plants and soil in the cold frame will warm up, absorbing the heat to help get them through the night. It’s a pretty slick way to not only extend your growing season, but with a cold frame can also start growing earlier in the spring.

Cold frames work so well that you will probably need to raise the lid or covering during the day on warmer days, so you won’t end up with your plants getting too hot. Yes, it works that well.

As far as what you can grow in a cold frame that’s up to you. I would suggest planting some of the semi-hardy vegetables that you enjoy like beets, broccoli, cabbage, carrots, and kale etc. Semi-hardy means that they can take a little cold better than some of the more tender plants such as tomatoes, squash, and cucumbers etc. With these tender plants, if the temp inside the cold frame gets below freezing, they are pretty much done. But a slight dip below freezing won’t destroy semi-hardy plants.

It’s a little early for a cold frame now, but with a little planning and effort, you’ll be ready to keep on growing when the cooler temperatures finally arrive. See you in the garden!

You can get answers to all your gardening questions by calling the Tulsa Master Gardeners Help Line at 918-746-3701, dropping by our Diagnostic Center at 4116 E. 15th Street, or by emailing us at mg@tulsamastergardeners.org. Photo: iStockPhoto