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Cloche for Duckweed

December 4, 2012

Problem: How to extend the duckweed growing season an extra month or two in the fall in KY?

Solution: Design a cloche over the pond using plastic sheeting with bricks to anchor it all at the base.

How to hold up the plastic, you say? For small kiddie pools, I’ve used recycled old tent frames of carbonite or strips of 1/8″ thick steel strips that were pre- rolled in my ex’s machine shop. Arrange igloo-style over the pool, stabbing the ends into the ground and tie together at the top where they meet. Then wrap in heavy clear plastic sheeting. I tried a couple of winters to neaten it up by cutting excess wads of plastic from a couple of sides of the cloche. It always ended horribly with tape coming loose in cold weather, right when I needed it the most. Now I simply roll the plastic vertically in at least a couple of places and preferably over the seam. Then I throw a rope around the bottom to secure it tightly. Stays put, especially with the bricks to anchor the plastic to the ground and eliminate drafts.

Once I had plenty of storm windows and fashioned a five sided dome, using a smaller flat storm window over the top- gaps and all.  Used plenty of ducktape. It was wonky and I was glad to have had the foresight to situate it in the backyard. However ungainly, it did extend my duckweed growing season out by another six weeks or so.

One nice thing about duckweed in a hot house like this- you don’t need to worry about it getting too hot as with terrestrial plants. The water acts as a buffer against a few days of it getting back up to sunny 70 degrees F. To harvest, I loosen the string enough to slip my hand or a net into the pond and pull out as much as I want for green mulching my indoor potted plants. Mostly, I just like to watch it continue to grow long after its terrestrial counterparts have succumbed to heavy frost. Now if I can just produce it in an environment where it is healthy to eat…


2 Comments leave one →
  1. Susan Munroe permalink
    December 6, 2012 2:06 pm

    There is a heavy (9 gauge, slightly thicker than 1/8″) single-strand wire, galvanized, that is called TENSION WIRE for use with chain-link fencing. It comes in a coil about 18-24″ in diameter (so it is already somewhat curved), and it is perfect for this use without having to use any kind of bending unit. But you will probably need bolt cutters to cut it.

    Both Lowes and Home Depot should carry it in lengths of 170 feet for about $22.

    There was a roll of it in the garage when I bought this place, and I’ve found quite a few uses for it for cloches and to cover beds with netting.



    • December 6, 2012 7:03 pm

      Sue, what a great idea. I used to use galvanized wire from a vineyard that I owned a few years ago. It was tough to cut but when bowed over veggies and both ends stuck deep in the ground, then intertwined with a crosswise piece running the length of the cloche, became quite stable. I forgot about wire. Thanks for sharing this.


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