Wednesday, October 10, 2012

UPDATE A Large Scale Wick Irrigation Experiment

I've had a couple of question about how this worked out and some details. First, the rope I used was the cheapest sort of braided nylon rope. I've used 1/2-inch and 5/8-inch and have no doubt that any diameter will wick. I've not tried any other materials, but I see no reason why rayon and cotton won't work. Try poly at your own risk.

Note again that you have to sort of jump start any wicking. The system has to be wet for wicking to begin. A dry rope in dry soil won't wick. No problem. Just water the container the first time.

Now, as to how it worked. While it certainly did wick and continued to water the containers through the summer, merely getting water wasn't enough to save tender plants in the brutal Texas heat. I think this is a good project for milder weather outdoors or for a greenhouse.

I did another wicking container project using a stock watering tank, the galvanized farm sort, about three feet across. I used five cheap plastic flower pots inverted on the bottom, each pot having a "mousehole" cut into the downside edge to let water in and out. The pots support a piece of expanded aluminum mesh I happened to have. It supports a piece of coarse weave nylon fabric, something salvaged from a large bag of unknown use. Any open-work support and any non-rotting fabric capable of holding dirt on top will work. The old type plastic flourescent light grates come to mind.

A 1-1/2-inch PVC pipe penetrates the support layer and has a mousehole cut into the bottom end. This is for filling the space at the bottom with the water supply. The support layer is also penetrated by five pieces of the same nylon rope used in the other project. As the soil is added, the upper ends of the rope are wound around in it and some distance above the support layer. I left about a foot to curl in the bottom of the reservoir and a foot to wind around in the soil.

One last touch is to drill a small hole in the side of the container. This will prevent it flooding in the rain, and it gives you an indication when you have filled the reservoir almost up to the support layer.

I use this one for herbs, although an aggressing sage reached shrub size and took over. I'll do another one for other herbs. It has kept the plants well watered with no attention but occasionally filling the reservoir. Note, though, if you grow very much in it, you will be surprised as how much water it uses. It's a good lesson in how much water these plants demand.