Using Row Covers for an Extended Fall Harvest

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Many leafy greens and root crops are frost tolerant into temperatures as low as the 20s. I generally cover my lettuce, spinach and kale and continue to harvest them—sometimes as late as Christmas. If you live further south, you might be able to keep these plants going all winter long with proper protection. On sunny days, row covers also trap heat to encourage more growth. 

Row covers are cheaper and lighter than cold frames, and they can easily be moved to where they’re needed to provide protection for several weeks.

Covering Plants With Row Covers

Row covers consist of transparent, lightweight, protective coverings in the shape of small tunnels. Lots of crops will carry on a while longer if they’re just given a little warmth and shelter—such as summer salads, spinach, greens, cucumbers, peppers, tomatoes, and green beans. And by using row covers, those late-season stragglers can keep producing for a two or three more weeks in the fall.

Look for spunbond frost blankets or row covers from a garden supply store. Most are made from polypropylene fabric, then held up with metal or PVC hoops. The covers need to be transparent and clean to let lots of light in, given low-light levels at this time of year. You could also use fabric row covers that do let in water, but they will not give as much protection or warmth as other covers. 

Also, you need to be able to open or roll back for watering since rain won’t reach the plants. It’s important that covers can be pinned down so that they don’t blow away or tear. By anchoring the sides of fabric to the soil, you are trapping air to create an insulating space. Because they’re so plentiful where I live, I use rocks to weigh down the sides of the row cover, but bricks are another option.

Row Cover Size

The row covers need to be wide and tall enough for your crops so they don’t touch the sides when fully grown so this requires some kind of support. I have metal hoops for the spinach and lettuce. If you’re building hoops from PVC, I’d space hoops about two feet apart; you will need a hacksaw to cut the pipe. To hold up the PVC supports, you can hammer in rebar stakes. Ensure the stakes are about 5 to 6 inches out of the ground, and make sure they have a smaller diameter than the PVC pipe so that the pipe can slip over them for easy installation and removal.

My kale was growing much too high for my own metal hoops. Luckily, it was up against a fence, so I decided to be creative in building their support. I took some bamboo poles and inserted them in the ground in front of the kale. Then I placed another bamboo across the middle of the front to keep the plants away from the front of the plastic.

Then I took some small hoops and tied them to the top of the bamboo poles.

The other side of the hoop was clipped to the fence using clothespins and I tied them to the fence (snow can be quite heavy).

I draped my row cover over the whole structure, pinned in places and grounded with rocks.

Be sure to pick out all the fallen leaves!

I did the same with the spinach.

You really do need to use some heavy rocks or the wind will just blow the cover off. I’m planning on having a nice, big salad for my dinner party on Saturday. The lettuce does need to be thinned and I’ll toss it with a bit of kale and spinach. Yum!

Handy Video Demonstrations

See how to make a row cover tunnel.

See more about using cold frames, row covers, hoop houses, and other ideas.