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.


Filed under gardening, irrigation, water

14 responses to “DIY terra cotta watering system

  1. ingenious idea. hope it works out well for you. i finally planted my balcony garden last night – had to do it in the dark but it’s done, phew!

  2. liz

    Thanks, Julia. Glad to hear your garden’s all planted!

  3. Tim

    How did your home-made ollas work out for you? Did they inclrease garden production? I live in Colorado Springs, CO and it is very dry here; hoping to get a report on how your ollas performed before making them myself.

    Thank you

    • liz

      Well… It turns out it was a really wet year here on the East Coast, so we had way too much water and a really horrible growing season. The only consolation (sort of) was that we weren’t the only ones who basically didn’t get much out of the garden last year. However, we did manage to test these at the start of summer before all the rain started, and while they worked well for our purposes, I think we’d need a larger pot with thicker walls to make it work for drier climates or for longer watering intervals. They definitely do consistently provide water directly to the roots of your plants if you position them properly, so they work in that respect, but it will take some experimenting to see how long you can go without watering and how many you’ll need in your garden, as this will vary according to climate and soil conditions.

  4. april

    I have just stumbled upon the olla myself and as a horticulturist who love to conserve water this seems like a great tool. I have started making ollas on my wheel at home and am thinking about trying to sell them to other gardeners in Oregon. Any advise?

    • liz

      Hmm… for some reason your comment didn’t come through my email, April, so this may be a little late. I’d try varying the widths of the ollas (and the sizes) to see how long they hold water. Vary soil types, too, to get an idea of how quickly the water diffuses through the terracotta. Finally, make sure you can cover them — slugs, in particular, love the wet environment they provide. Best of luck!

    • Elaine Mezzo

      Hi April, I am a gardener in Eastern Oregon and am fascinated in ollas. I have been looking for some to use in my garden by googling ollas in Oregon! I would love to correspond with you regarding ollas. Are you still making them? I see this is an old post, so I hope you have been successful in making them. If you reply to me this site will notify me. Thanks so much Elaine

      • Michele Albert

        Elaine did you ever get ans. I live in Central Oregon and looking for some.

      • BD

        Hi everyone I found ollas at Territorial Seed in Cottage Grove Oregon. Drove all the way from Portland to pick mine up due to shipping cost. I used these in the past in a SW garden. Worth the drive. For those who have never used them, place a small wire landscaper’s flag in a cork and drop it in. You will see your water level even from across the garden bed. I use irrigation tubing lay out to fill all mine at once. In my SW garden I put it on a timer to fill just before sunrise

  5. jennifer hyatt

    I just saw your comment and I was doing some research and I found this amazing site that gives a lot of detail of what kinds of ollas are needed to water what area. If you ever look here again, this might be useful to you:

  6. MPbusyB

    Liz – I have used plastic gallon milk/water jugs in the past. I punch a couple of holes in the lid, fill the container with water, cap it, stick it upside-down in the garden and watch to make sure the water slowly seeps into the soil. Sometimes it worked; other times the holes got clogged with soil. So I really love this idea of ollas. It will work great watering our banana trees that need more water than most of the rest of the garden. I think it’s also a great way to water transplants and new plants until they get established. Thanks!

  7. Pingback: Dry Garden Ideas | Suburbhomestead's Blog

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