Extending the growing season with row covers

DIY garden row cover
Phot by Brad Sylvester. Copyright 2012.

If a New Hampshire garden is to compete with a garden in Georgia for total yield over a span of twelve months in the 1000 Pound Challenge, a key factor with be the ability of the northern garden to extend the growing season. One way to do that is with the use of row covers.

Row covers are used both in the early spring and late autumn to protect garden plants from cold and frost damage. They provide a crude greenhouse for an outdoor garden by covering the garden and trapping ground heat to keep the plants warm enough to survive cold early spring or late autumn nights.

They should be made of a material that lets sunlight in, but which keeps frost out and heat in. Generally, that means plastic sheeting. In my case, I had some battered plastic that I recently used to help protect my in-laws' furniture while moving it in an open truck bed during a light rain. Rather than throw out the plastic, I recycled it by making garden row covers.

I used flexible green branches from my backyard as the hoops for the row covers, and longer branches as the framing members. Row covers are actually pretty easy to build. I have prepared a slide show with step by step instructions for building your own garden row covers and a written a detailed account of the specific benefits of row covers.

With the row covers in place, I can plant seeds directly into the garden even though we have another month of frost danger, or I can transplant seedlings that I started indoors out into the garden. This will add weeks of productive harvesting to the garden.

By using row covers again in the fall, I can grow crops like lettuce, spinach and other plants that aren't as sensitive to shortened daylight hours, well into late autumn or even early winter.

Techniques like the use of row covers make a huge difference in the total annual yield of gardens in regions with short growing seasons. In New Hampshire, row covers can increase the effective growing season by 50-100% depending upon the severity of the weather.

If I'm going to have any chance at the 1000 Pound Challenge, I'll need row covers to give my garden a longer harvest time along with a number of other techniques designed to increase the yield per square foot of garden space.