DIY terra cotta watering system

This state has no shortage of water.  We can waste it as we please, without worrying about drought warnings, crop failures, or growing tired of countless images of cracked, parched earth on the TV screen.  This doesn’t mean we should.  Water is one of those things that you quickly learn to appreciate if you don’t have enough of it.  I know I hate wasting water after spending all those years in the San Joaquin Valley, where droughts are pretty much the norm.

Sometimes, I think the world would change almost instantly if those without water shortages were forced to live with drought for a few months. Just enough to realize that water is a limited natural resource, just like oil.  Unlike oil, it’s a resource we can’t survive without.

So, what does this have to do with the photos I’ve posted today? Well, I thought I’d share a sort of primitive drip irrigation method I stumbled across recently, which makes use of buried terra cotta vessels called ollas.  There’s an excellent post here on how this method works.  It’s designed for dry climates, but we decided to install them this summer to regulate our water use a little more, and to make life easier when we went out of town.  Essentially, we’re taking advantage of the permeable properties of unglazed terra cotta to distribute water to your garden slowly and efficiently, minimizing water loss from evaporation.  And yes, this is a new experiment this year — I’ll be reporting back on how well all of this works.  For now, here’s a little tutorial on how I made them, so you can have a shot at this yourself:

1. Find unglazed terra cotta pots and saucers (or just use 2 pots of the same size — I’ll get to that in a bit).  We chose 6″ versions from Home Depot, which cost $1.50 each.  You will also need sandpaper and a waterproof sealant.  The 100% silicon sealant for doors and windows (which you can find in the paint section of Home Depot or any major hardware store) works quite well.

2. Sand the lips of the pots and saucers.  The pots and saucers in the background of the shot above are shown to illustrate how we’re going to glue the olla together; sanding will help the pot and saucer edges match up.  Make sure to clean off the surfaces you sand with a bit of water and let sit for an hour or two to dry before you continue.

3. Line the lip of the pot with silicon sealant (lots of it).  You want to make sure there are no gaps in between the pot and the saucer — otherwise you’ll have a water leak, which will defeat the whole purpose of this exercise.  Let this dry overnight, and check again for any gaps.  You might even want to test these for leaks before you put them in the ground.

If you’re using two pots instead of a pot and saucer to make your ollas, you’ll have to seal up one of the drainage holes as well.  I made one of these as a test, and just stuffed the whole with plastic wrap and then covered everything in silicon sealant.  This leaked.  More silicon fixed the problem, but you’ll definitely want to test this style of olla for leaks, because it’s difficult to visually confirm that you have a good seal on this sort of opening.

4. Bury the ollas in the garden so the saucer part and most of the pot is underground. You’ll basically bury these deep enough so just the open drainage hole is sticking up out of the ground.  This is so you can fill the ollas up periodically.  The first picture on this post should give you a good idea of how to position your olla.  Then, just fill them up, and cover the whole with a rock or something, so you don’t create a nice little mosquito nest in your garden. (As an aside, check out our pea shoots!  We installed the olla this week, and had planted these a while ago. I can’t wait until they start flowering…)

Simple enough, right?  As you might guess, the size and thickness of your olla will determine how the water is distributed, so you may need bigger pots, etc, but for a small vegetable garden like ours (a 10″x4″ plot), I think these should be adequate. If you have planters, you can buy small versions of this (kind of like this) (or make some with little pots, if you can find them?).  We tried a version of these plant nannys last year that used plastic 2 liter bottles as the water reservoir, and had trouble getting a good seal between the bottle and the terra cotta input in the garden bed, but they may be worth trying if you have a container garden.

I suppose now we’ll see how long I can put off watering the garden with these in place.  Though with all the rain we’ve had lately, I don’t think we’ll have anything to worry about any time soon.