The Greedy Gardner
In the movie “Wall Street”, Gordon Gekko said: “Greed is good”. After forty years of gardening, I have come to the sad realization that I am indeed a greedy gardener, though I’m not at all sure that’s a good thing. For me, the early vegetables are never early enough, and the fall growing season is never long enough. How often have I planted in the late winter or early spring only to be hit by a late frost, resulting in damaged — — or worse yet dead seedlings, not to mention the curse of low soil temperatures, resulting in poor or no seed germination?
My grandmother, an avid gardener, must take some of the blame for this learned attribute of mine. As a child, I remember visiting her late one winter day as she was in the garden planting spinach, peas and radishes. With a cocky smirk on my face, I asked if she was “practicing.” With a bit of a frown, she inquired as to what I was trying to say. With a confident voice, I responded, “Whatever you are planting isn’t going to amount to anything because if they do come up, they’re going to be killed by a late freeze.” I was at once informed somewhat abruptly that “if a gardener doesn’t lose a few things in the spring and in fall, they’re not getting their money’s worth.” I humbly turned and headed to the house. BOY, would she be proud of my gardening habits today!
I have indeed taken that old cliché “plant early and plant often” to a higher level. Some years back I started using row covers and found they reduce the risk of a late “killing” frost, hasten the growth of early crops, and improve seed germination rates. Thankfully, these row covers have greatly reduced my “practice planting” opportunities. In addition, when row covers are used in the fall, they can extend the fall growing season, and that’s especially true if you combine row covers with raised beds.
The use of protective coverings to produce a miniature greenhouse effect is certainly not a new idea. A quick trip to one of our local antique shops will often led to the discovery of glass bell jars, which were commonly placed over individual plants in the early 1900’s by European gardeners. And more than a few of us recall using newspapers to make paper “hats” to place over tender tomato and pepper seedlings to protect them from a late frost.
The main purpose of row covers in the late winter or early spring is to provide protection from adverse weather conditions and increase air and soil temperatures during the initial stages of growth. The improved growth of plants under row covers can be attributed to higher air and soil temperatures. Row covers, when utilized in conjunction with raised beds, often allow crops to be planted 3-4 weeks before traditional planting. Now that’s a head start to make my grandmother envious!
Two basic types of row cover material are available: plastic (which is supported by plastic or metal hoops) and fabric (which also may be supported by plastic or metal hoops but often are let to float, resting directly on plants). If you decide to use clear plastic, go for a length of 5 to 8 feet wide. Plastic comes in a range of thicknesses, measured in millimeters, ranging from 1 ½ mm to 8 mm, the greater the thicknesses, the higher the insulation value, and thus, greater heat retention. The down side of a thicker material is that less light passes through to the plants. The sides and ends of the row covers are secured in place by anchoring the edges with one of the following methods:
- Ground stakes
- Row cover hand pegs
- Anchoring pins
- Plastic bottles filled with water or sand.
The temperature under plastic row covers needs monitoring as heat will build up and can be 20-25 degrees hotter than the outside air temperatures. As a general rule, when the air temperatures outside of the row cover reaches 60º-65º F, the ends should be opened to provide ventilation and cooling to prevent plant damage.
One advantage of utilizing a supported row cover is that as temperatures rise, you can prevent bolting of lettuce and other plants that are not tolerant of warm temperatures. You simply remove the row cover and drape a shade cloth over the frame, and your lettuce will continue growing — and not going to seed — in that nice, cool shade.
Most floating row covers are thin, lightweight, porous or spun-bonded materials. They are placed directly over the plants, leaving some slack for movement and room for plant growth. As with plastic row covers, the edges of floating row covers are secured by anchoring the edges with dirt or stones or metal staples you can find at gardening stores. Floating row covers provide only a few degrees of protection, but they are an excellent barrier for a wide range of pests. However, if the crop requires pollination, such as squash, the row cover needs to be removed when plants start to flower or you’ll need to pollinate by hand.
There are numerous resources, including various web sites and seed catalogs that provide “How To” instructions for row covers as well as offer materials for constructing row covers.
- Be aware that manufactures and vendors of row covers hype their products, claiming remarkable results. Nevertheless, there’s science to support some claims, at least to some extent. An article published by Washington State University (“Row Covers for Vegetable Gardens –Community Horticulture Fact Sheet #19” http://ext100.wsu.edu/king/wp-content/uploads/sites/17/2014/02/Row-Covers-for-Vegetable-Gardens1.pdf) suggests that university research has confirmed a number of row cover benefits:
- Early Yields
- Increased Yields
- Frost protection
- Pest Protection
- Water Conservation
This article describes an interesting trial conducted in New Hampshire, which involved both covered and non-covered seedbeds of nine varieties of lettuce and three types of spinach, which were planted in October. By spring those beds with floating row covers had perfect stands of lettuce and spinach. In those beds without row covers, not a single plant survived the winter. The researchers were bewildered by the dramatic results because the temperatures recorded under the row covers were the same as without row covers (-2 degrees F). The researchers theorized that the frost heaving and drying was less severe under the row cover material! They are continuing their trials, so maybe soon we’ll know even more about row covers. In the meantime, I encourage you to try some row covers this spring. With a row cover, you can afford to get greedy!
Virginia Tech Publication 426-381 “Season Extenders” http://pubs.ext.vt.edu/426/426-381/426-381.html
“Vegetable Production Under Row Covers,” The Virginia Gardener, Volume 6 Number 2, February 1987 (S.B. Sterrer)
“The Use of Row covers in the Home Garden: Cornell University Ecogardening Factsheet #6,”
“Row Covers for Vegetable Gardens” (Washington State University Community Horticulture Fact Sheet #19) http://ext100.wsu.edu/king/wp-content/uploads/sites/17/2014/02/Row-Covers-for-Vegetable-Gardens1.pdf