Tuesday, May 5, 2020

Let's Talk Row Covers

Tis row cover season.  Frost cover season.  Take it off and put back it on season.

I have my tomato plants in the cold frame.  The old and battered polycarbonate panels combined with a 50% sun shade allow me to harden off the seedlings.  I have to regulate how far open the lid is which regulates both the maximum temperature, and the amount of wind.  I always hope that the sunny days will be on my days off so I can adjust to conditions every couple of hours.  Satisfaction is defying the weatherman's prediction and knowing you got your cold frame set up right when you left for the office at 7am.

I am still baby-sitting the Chilly Pear tree.  It has now had its cover off more than on, but we are expecting cold nights this week, so it will be an on and off week.  The tree has done remarkably well under near blizzard conditions.  This past Friday we stopped by Tractor Supply, and they had a batch of fully leafed out ornamental trees in their parking lot that were frost burned all to heck.  That made me feel better.

I have lettuce babies and some herb seeds in pots in the garden.  I've been regulating their protection also with a plastic storage tub.

This not only keeps the soil warmer, it also is a humidity dome
preventing the seeds from drying out as they germinate
And then there are the Cauliflowers, Broccoli and Brussels Sprouts.  Last year I planted them in the Strawberry Bed which has a framework over it making it easy to apply a row cover with clothes pins.  This year there are Strawberries back in there so the cole crops had to go into the main garden.  If I don't want to be fighting little green worms every day for the next four or five months (and I certainly don't), it is imperative that the cole crops be covered from day one to keep the cabbage moths off.  Additionally, we have been having pretty stiff winds for at least a portion of every day and the young seedlings, which despite being raised with a fan on them daily, would still be dehydrated, battered and even twisted off.  The row cover buffers the wind.

There are a lot of products of different materials and dimensions out there that are marketed for supporting the row covers and building tunnels.  Additionally, I've seen a lot of examples on the internet of people supporting tunnels with bent PVC pipes.  This hasn't actually been a time where you can just wander into Home Depot and start bending PVC pipes to see which will work for this application.  So, with the challenge presented to my clever husband, I found that we had a substantial roll of leftover black water pipe hanging around.  I knew I wanted the hoops to be about six feet from end to end, which matches my existing bent pipe structures and row cover material.  Not only the strawberry covers, but this section shown below can be moved anywhere in the garden and is useful for either protecting lettuce in the fall or new plants in the spring.

This hoop house can be moved over the nursery plants at night to protect from late frost.
I have collected a lot of frost covers and remnants of frost covers over the years.  They typically come in widths of six feet, ten feet or twelve feet.  The lengths vary from ten feet to fifty feet (and they are not easy to cut neatly).  The frost protection varies from "summer weight" which rates about 28 degrees and will protect from a light frost to "garden quilts" which protect down to 24 degrees.  The thickness also affects the light transmission.  Summer wight allows 85% of light transmission, and the heaviest of the quilts allow 60%.  There are also shade cloths that block at least 50% of the sun.

Summer weight is what I want to use for most of the season, but it is easily torn and doesn't hold up well to battering winds and heavy rains (or hail or snow load).  After a few years of exposure to UV rays and other weather conditions it becomes even more fragile.  With potentially violent weather in March and April I do best with the heavier garden quilts for starters.

I attempt to keep all of this stuff sorted out by writing the dimensions and frost protection in a corner of the cloth with black marker.  And this stuff is AWFUL to fold neatly.  You think folding a fitted bedsheet is tough, just try wrestling with a 10' x 20' piece of eiderdown on a windy day.  So once you get it folded and put away, you are not going to want to unfold it just to see what size it is!

I had been planning to drive re-rod into the soil inside the sides of the beds, but my husband convinced me to drill into the wood itself to set the base.  The hole is not particularly tight on the rod.  I will be able to pull it out with the aid of locking pliers.  The hole is four inches deep.

The half inch re-rod slips inside half inch pipe firmly but easily.  The taller your rod, the more upright the sides of your hoops will be.

Now lets talk fasteners.  The catalogs which sell row covers don't present any clues as to how you are supposed to hold down the row covers which I think is a missed marketing opportunity.  Why not sell all of the hardware people will need for the cover/support combination they are selling?  Heck, even write one of those helpful articles for the information portion of the website to take the guess-work out of it.  Yes, you can weigh them down with rocks or poles or even bury the sides in the soil.  You could use earth staples.  But you are going to ruin your row cover pretty quick, and it will not be easily moved for watering or weeding.

I spent the winter months surfing the net for examples and products, and using what experience I have to imagine how all this would work easily and hold up, stay secure yet be easy to remove for watering or weeding, not to mention harvesting.  These half inch Bootstrap Farmer clamps are pricey, but brilliant.  The one down-side is that they require a bit of force to remove, and you may end up tearing a lightweight cloth if you have to repeatedly remove them.
 There are less expensive versions of PVC clamps. 
You could use scraps of garden hose.

Tekton makes a variety of sizes of strong spring clamps.  We have a bunch of them accumulated around the garden shed.  The 3/4 inch size work perfectly on the 1/2 inch water pipe.  And they are much less costly than the Bootstrap clamps above.
The Earth Staples, which I have used in the past for pinning down covers, actually work brilliantly for gathering and containing the ends of the fabric as long as you are placing them in firm soil. 
The earth staple has a hole to pass the end of the row cover through and pin it down
With a six foot length of pipe, spanning three feet of bed, I knew from my existing frames that the ends would be almost two feet tall.  I needed enough material to drop two feet and then insert into whatever I'm pinning it with.  My beds are 12 feet long (outer dimension) so I needed a length of fabric at least 18 feet long. 
12+2+2+slack=18 feet

This worked out perfectly.  Thankfully, I had an existing row cover that length so I could try it before I ordered fresh material for this season.  It isn't particularly expensive to replace.

So this is my finished row cover.  I can loosen the ends, slide the covers up one side of the ribs, and clamp them up giving me easy access to the plants.  I used the blue Bootstrap Farmer clamps (which I already had) on the ridge to stabilize the tunnel.  One downside of the black Tekton clamps is that the jaws are a little rough and can snag the fabric.  The blue clamps do not have the problem.  I am going to try placing some neoprene squares under those clamps to cushion the fabric.

The pipes are placed every 40 inches.  I had originally planned five supports instead of four, but we ended up drilling into the beds and there is already a re-rod drilled into the center of each side.  I would have had to shift everything off center and the four ribs seem sufficient for summer.  If you were extending the season into the fall with a chance of snow weighing down the cover, closer together would be better.

These covers also look neat and tidy.  I expect they will hold up well.  The covers will need to be replaced every few years, and if the pipe needs to be replaced, that will be simple to do.


  1. Really good, informative post. I'm happy to see so many folks "getting into" gardening this year but have real fears that the thought that they will be to raise a substantial amount of their own food as first time gardeners is going to be extremely discouraging. There's one whole heckuva lot more to gardening than one would EVER dream, isn't there!

    1. There IS a lot to it. Yes, you can just throw some seeds in the dirt. But it had better be pretty good dirt and the right timing. I see so many people with these monster plants they are just itching to get outside, while the rest of us know that it really isn't practical to expect to eat zucchini or green beans in May in most of the country. And if you're going to plant early, be prepared for frost. If anyone is a fan of Green Acres they will remember Oliver digging up hundreds of tomato plants and moving them into the house! You can't just give up. You have to be clever, determined and resilient.