Any enthusiastic gardener will want to extend the natural planting season no matter how short or long it may be. I learned to make use of hoop tunnels and row covers to get an extra few weeks of yummy produce, even when we lived in the warm temps of the North Carolina coast.
I don’t remember how I discovered hoop tunnels, but they’re a great way to extend your growing season. Hoop tunnels help insulate your plants from both cold winds and cooler temperatures. It doesn’t mean that I’ll be able to harvest tomatoes here in Zone 6b in January; some things just aren’t meant to be. But it does mean that we can eat freshly harvested greens in January, and that we can start our tender seedlings earlier each spring.
Our hoop tunnels are made from PVC pipe, anchored with short pieces of rebar hammered into the ground (just slide the PVC over the end of the rebar that remains above ground). Once the curved “hoops” are in place, holes are drilled into them to attach horizontal pieces of PVC onto the top and either side (zip ties work great) to keep the plastic covering from sagging onto the plants below. I cover the hoops with contractor plastic bought at a home improvement store but greenhouse film, which lasts longer, is available through a number of online suppliers (if you prefer a ‘ready-made’ product, complete hoop tunnels are available as well).
Once the plastic is draped over the hoops, it’s anchored at each end and along the sides to block the wind. I use a 2 x 4 or a long tree branch as an anchor for the sides. That allows quick access to the plants inside. Rocks or bags of sand anchor the ends. An outdoor thermometer inside each tunnel is necessary for monitoring the temperature. You’ll be surprised at how warm it can get in a hoop tunnel on a sunny day and, if it starts to get too warm, you simply raise the plastic a bit to let cooler air mingle with the warm.
According to Eliot Coleman, author of The Four Season Harvest, the growing season can be extended even further by layering your frost protection. To accomplish this, simply add a layer of row cover or frost blanket under the hoop tunnels. The row cover rests on top of the plants, giving one layer of protection and the plastic on the hoop tunnel adds yet more insulation. I’ll be trying that for the first time this year. Most row covers add four degrees of frost protection per layer. Of course, each added layer cuts down on the amount of light the plants receive so we’ll experiment with just a single layer of row cover in addition to the plastic on the hoop tunnels. We’ll be putting our broccoli, cabbage and kale transplants out a couple of weeks earlier than called for in the NC ag extension guide and we’ll see how we do!
