Wednesday, February 29, 2012

Growing Tomatoes with Kozy Coats

Heirloom tomato harvest, including 'Anna Russian', 'Oxheart Pink', 'Black Brandywine', 'Yellow Brandywine', 'Crimson Cushion', 'Black Prince'
I've been experimenting with growing tomatoes using Kozy Coats (which are very similar to Wall-o-Waters). That's those weird-looking plastic cones made of tubes filled with water. (The only difference between Kozy Coats and Wall-o-Waters is that the KCs are red and the W-o-Ws are green.)
Kozy Coats with tomato plants inside, late April
 The basic idea is that you can put your tomato transplants out earlier than normal inside the Kozy Coats, which should result in an earlier harvest. The tubes of water heat up during the day, then give off warmth at night. Also, the shape of the structure itself protects plants from cold winds and traps warm air inside. It works like a little mini-greenhouse/cloche for each tomato. The company claims that you can set your plants out when the ground is still frozen, by setting up the Kozy Coat a couple weeks early to thaw the soil. I've never tried to go quite THAT early, but I have planted tomatoes as early as April 5 (where our "normal" tomato planting time is about May 20). In April and early May we definitely still get freezing temps at night here, and plenty of cold days as well.

Tomato growing inside Kozy Koat, late April
So the question is, does it work? Short answer: yes. I definitely get earlier harvests this way. More complicated question: is it worth it?  Answer: it depends...

Tomato plants in June
Using Kozy Coats requires quite a bit of extra work, and a certain amount of peril (mostly to the plants, although the gardener is in significant danger of getting SOAKING wet when trying to fill the blasted things). Putting plants in the ground six weeks earlier gives me tomatoes in hand only about two weeks earlier than normal. Is two more weeks of tomatoes worth the work and risk? Only you can decide...

Things that can/will go wrong:
  • Disease and death - Light is transmitted through the colored plastic, and air does circulate a little through the top, but both air circulation and light transmission are diminished. If you hit a long stretch of particularly gray, damp weather, your tomatoes may get diseased, grow poorly (resulting in no earlier harvest), or even die. In six years of growing tomatoes using Kozy Coats I've lost only one plant. But success is definitely better in years when spring days are bright and sunny. Cold nights, however, really do not seem to be an issue at all, nor does snow.
  • Sunburn - When temps warm up, you need to remove the Kozy Coats, or the tomatoes can actually fry in there. This needs to be handled delicately, and you have the same potential problems you do with hardening plants off. Just popping the protection off suddenly, especially on a bright day, will cause the leaves to get sunburned and perhaps fall off. Ideally you want to take them off for a few hours each day, putting them back on at night, and extending the fresh-air time gradually. (I am much too lazy to follow my own advice here, and no plant has ever died of sunburn for me, but they look pretty awful when they first come out.)
  • Cold wet gardener - Filling the tubes with water is probably a 3-person job at least (which I always do by myself, since my husband and daughter magically disappear when non-fun tasks arise). The Kozy Coats stand up well once all the tubes are filled, but it's like trying to hold up a heavy mass of drunken jello until then. It's not physically possible to hold open the tube for filling without getting extremely wet, even if you miraculously manage not to topple any onto your feet. And remember, it's now 4-6 weeks before you're tomatoes want to be outside, so prepare to be very, VERY cold.
  • Limited choice - If you buy your tomato transplants, you will find at best limited availability of varieties so early in the season. In early days before I got into seed starting, I ended up buying varieties I was not particularly interested in (even - shudder - HYBRIDS!) because that was all I could find for sale in April. So the bad news is you'll just have to begin your heirloom tomato seed starting mania, if you've somehow managed to escape it so far :-)
  • Your neighbors will look at you real funny. But we're all used to that, right?
So am I willing to risk all of this just for two measly extra weeks of tomatoes? YOU BET I AM! And if you have eaten one of these guys plucked straight from the vine, you surely understand why.
Tomato 'Brandywine'


  1. Very interesting. Do you start your own seeds? We will be starting our seeds soon and I think that these Kozy Coats will be a good idea--if we can find them here. Good post. Good information.

    1. Yes, I have gotten very into starting seeds and it is a lot of fun! Gives me something to do in the winter before the garden gets going. I'll be starting tomatoes this week, so they'll be ready to put out in early April. You can get the KCs or WOWs from mail order companies if they're not in local stores.

  2. I use these in the colder part of the season to give my tomato plants a head start. I check them every day to make sure all is well. Mine are green, but the red improves growth. My neighbors have asked me about these. They do look odd if you are not accustomed to seeing them.

    1. Yes I have heard that claim from the company that the red color somehow improves growth. Not sure if it's really true - I just picked up the red ones because that's what was available. The red definitely stands out in the yard more and attracts neighbor attention! Mostly people are just sincerely curious - what the heck is that?

  3. I have never seen these before and am really intrigued. I wonder where I would find them here in Canada?

  4. Here we can pick them up at local garden centers and even bigger home improvement stores, and they're also commonly available through mail-order. In the U.S. for example Jung's, Gardener's Supply, and all carry them. Check your local garden supply mail order companies - I betcha they're available in Canada too. They are particularly useful people like us with shorter/cooler growing seasons.

  5. Lee Valley sells them in Canada.
    To make filling easier I set the kc up around a lg pot with soil in it. When tubes are full I lift the pot out. It helps hold it up when filling.

  6. I have used both the red and the green and didn't see a difference, besides the fact that the red ones were very flimsy (won't buy that brand again). I don't remove mine, even in 90-100 degree heat, and I have never had a problem. I left a couple on the whole summer last year just to see how they would do.

    1. Wow, I have never tried leaving mine on all summer! By summer my tomatoes start growing out of the top and get all squished. We also have major problems up here with blight, mildew, etc. so I'm not sure keeping the base enclosed like that would be a good idea for me... but perhaps in a dry climate it works well. Thanks for the idea!

  7. I've been using them for approximately five years and it always amaze me when my tomato plants survive to -15C°. When the weather gets warmer, I'm always anxious to open the kozycoats to see if my tomato plants are alive. I never lost a plant except when I forgot to open my kozycoats in a really warm day I had a pepper plant that died of heat.I do start my own seeds and when you use extra early varieties you can have tomatoes one month before everyone.You can even start your seeds in January to gain more time. I also use pots to hold my kozycoats do they do not tumble. I leave my kozycoats all summer long, but obviously I leave it open so the plant can grow out of it.


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