Growing with Floating Row Cover

By Tanya Wohlsclagel, Master Gardener

A couple of years ago, as I wandered around the Hubbards Farm Market in early May, I looked on with envy.  Beet greens, kale, swiss chard.  These growers had perfect, robust, mouth watering greens to sell at a premium, early season price when I just had seedlings emerging.  In early June they had green and yellow beans, a whole month ahead of my crop.  I finally asked a grower how they are so far ahead of me.  She replied “Floating row cover, dear.”

At that time, I had been operating a small CSA, where I provided members with produce all growing season long.  I was so interested!  Not only would it be nice for me to be eating veggies sooner but it also would be impressive to my customers.  In 2010, I first experimented with floating row cover.   I ordered 5 x 250 feet from Stokes Seeds which was, at that time, about $85, tax and delivery in.  I purchased # 9 gauge wire from Home Hardware that had to be special ordered and took about a week to arrive.  My store charged just under $30, tax and delivery in. 

There are different grades of floating row cover which offer different levels of thickness and protection  Most grades are able to lay directly on sturdy plants.  As the plants grow, it will lift upward.  This is a helpful insect barrier for broccoli, cauliflower, cabbage, etc.  For less sturdy plants and seedlings, floating row cover can be erected with wire supports and used to construct low tunnels, also known as “caterpillars” and Johnny's Seeds has trademarked the name “Quick Hoops”.     

To build low tunnels, I cut the wire into 63 inch lengths and create hoops by pushing both ends into the ground.  Each hoop was placed about 3 feet apart.  I then dug a shallow trench on both sides along the length of the hoop area just outside of the hoops.  Before unraveling the row cover, I secured one end with rocks.  Then, with a helper, we unrolled to the length of the hoop area we were covering.  We cut that end, leaving lots of extra so we could secure it with rocks.  On the sides, we placed the row cover in the shallow trench and covered with the soil that was removed from the trench and also additional shovelfuls of soil, to further secure it.  The ends we twisted like a tootsie roll wrapper and secured with rocks.  Most of our vegetable garden area consists of raised beds surrounded by wood.  If I  placed a row cover near the edge, we wedged a 2”x2” by 8' or 2”x4” by 8' board between the wood and the outside of the hoops.  I weighed that down with rocks.  These low tunnels were a little easier to open for weeding and planting.  It is important that there are no flaps or gaps in the edge where the wind can get in and lift.  If you take the time to carefully secure your row cover in the beginning, you will spend less time chasing row covers around your yard.   

I used these row covers for more tasks than I initially imagined.  Very early in the season, as soon as the ground could be worked, I erected a row cover over a bed to warm the soil.  Using a thermometer after a few days, I found that the soil temperature inside the row cover was consistently a few degrees warmer than in the soil outside the row cover.  Some seeds will not germinate until a certain temperature is reached, so the row cover allowed me to start seeds earlier and have better germination.

The row cover also created a micro climate.  The soil would warm through the day and then at night, when temperatures dropped, the air inside the row cover would stay warmer.  The warmer temperatures allowed even cold tolerant plants to grow better.  Beets, chard, kale, carrots, peas, onions, spinach, and lettuce, to name a few, will germinate better and grow faster under a row cover. 

In my area, 15 minutes inland from Chester, last frost is often the long weekend in May but you can't really be sure until about June 10^th.  The row cover allowed me to change my last frost date.  I could plant frost sensitive plants like tomatoes, beans and cucumbers as soon as most nights were above freezing.  If the occasional cold night set in, the row cover micro climate kept the plants from freezing. 

I also used the row covers for heat loving plants.  Basil was twice as successful at germinating under the row cover versus not under the row cover.  It also grew faster and was bigger than the plants subject to the wind, cooler temperatures and insects.  Eggplant and peppers, notorious heat lovers,  also preferred life under the row cover. 

The row covers even made hardening off easier.  Transplants normally taken from under lights and then put outside would have to be done gradually over the course of a few days.  The row cover protected the transplants from wind and shaded them from the sun just enough that you could transplant most plants without hardening off at all.  If, later in the season you decide to uncover your plants permanently, you may have to do so gradually at that point, if the weather is very hot.  In the long run, the row cover saves time with hardening off because life under the row cover is “part way” to outdoor life. 

The row cover was a great insect barrier.  I started zucchini and cucumber seeds under the row cover and kept them covered until they were well established plants.  This allowed them to survive attacks from the cucumber beetle.  Lettuce, beet greens and spinach didn't have holes in the leaves.  If you secure the row cover over insects that are already there, you will have to find and remove them.  The row cover even protected plants from predators like deer and rabbits. Even chickens that escaped from the nearby pen could not invade the row covered areas.

The row cover also extended the season into the fall.  We started seeds late in the summer for a second crop of beans and carrots.  We also covered established plants, like kale, so we could harvest right to December.  At the end of the season, the row cover material and the hoops can be stored and used again in future years. 

The row cover in our vegetable garden turned out to be much more useful and successful than initially thought.   There were a few drawbacks, including drought.  Once the row cover fabric gets wet the first time, rain will penetrate the row cover, but things will be drier inside because of the warmer temperatures and vigorous  growth.  Watering and checking soil moisture is essential during warm, dry weather.  Also, the cover has to be pulled back for weeding, watering, harvesting and then carefully secured every time which is a bit inconvenient.  Another disadvantage is not seeing what is growing as you stroll around your gardens with a morning cup of tea.   If you use the row cover to start plants but then later want to uncover them when the weather warms, they do need to be uncovered gradually over a few days.  One last important consideration is that if your plants require pollination to fruit, the cover will have to be removed prior to or at least during flowering.

Though more effort is required, gardening with floating row covers has many advantages to the home vegetable gardener.  Extending the season, earlier fruits and veggies, producing healthy, more robust plants and protection from a wide variety of predators is worth the extra work. 

Happy Gardening!