It is possible, I have heard, to grow some vegetables all winter long - outdoors - in our backyards. I have never tried it, but it certainly sounds plausible enough to pique my interest.
The secret is to keep the plants warm. This is without the aide of artificial heat sources, but with a method that is similar to covering up with layers of blankets, tucking them in and letting the natural light do all the work. It might sound easy, but it isn't without a little work. Yet isn't the work worth it to be able to harvest fresh, homegrown vegetables any time of year?
Gardeners have been trying to beat Mother Nature for centuries, planting things that normally wouldn't grow here in winter. Every generation seems to have a better idea and sometimes these ideas give birth to new ideas.
Years ago the husband and I managed to extend the growing season by at least a month on either end with our raised bed hoop house. We came across the idea from a generic video we rented one day when there was nothing else to rent that we hadn't already seen, or at least anything else worth watching. The video explained how to build a wooden raised bed, gave dimensions that made sense and described how to install flexible, removeable hoops on which we would drape heavy, clear plastic. The bed could be as long as we wanted. Ours was 30 feet. The plastic was to keep out the cold air but let the sunlight in.
The beds should be no wider than four feet, the video explained. This is because a person's arm reach usually averages around two feet and this made it possible to pull weeds from either side without straining or having to walk onto the garden bed. Staying out of the garden bed avoided tamping down the soil.
It worked for us. We started plants and seeds more than a month earlier than usual by keeping the plastic tucked around the hoops and the ends of the bed. We took the plastic off the hoops for the summer, but at the end of the season, we managed to keep cold tender plants going for a month longer than usual, even after a few good frosts.
We did this for a few years until we lost interest. We basically did it just to see if we could and the food we raised wasn't necessary to feed our family.
But now I'm seeing articles and reports that some vegetables, mostly some varieties of lettuce and spinach and other greens, can be harvested all winter long with a similar set up. While we were anxious to see if we could grow earlier and longer than our season permitted, this method claims some vegetables can be grown and harvest all winter long.
This time, instead of using clear plastic, which is no longer recommended, floating row cover is the blanket that keeps plants warm.
I love floating row cover. I use it mostly in spring to keep early insects off of my seedlings. The cover enables sunlight and water to permeate its fabric, yet it affords a layer of protection similar to pulling a blanket up over our laps while we watch TV in the evening. Row covers come in different strengths and layering the row cover can offer even more protection just as though we added a second or third blanket to our laps.
Many gardeners suggest making the hoop houses portable so they can be moved from one garden bed to the other offering a chance to rotate the crops each season and this is a good idea, but if that isn't possible, one garden bed with a permanent hoop set-up will work.
The important thing to remember is to tuck the cover completely around the bed including both ends and secure it to the ground by either laying boards or pinning it tightly. Like the clear plastic the husband and I used in the 1980s, the object is to keep the cold air out.
Of course, you can lift the plastic to harvest your lettuce or spinach, but cover it back up immediately and don't lift it again until the next harvest.