The Corpus Callosum

Tech Tip #6

Forget to water your tomato plants?  Try using ollas
(pronounced oy-ya).   is Spanish for pot,
as in clay pot.  

What you do is to get
unglazed clay pots, bury them near the plants, and put water in them.
 The water leaks out very slowly, because the unglazed clay is
permeable.  This creates a water plume underground.  


What you see here are ollas, each made from two unglazed clay pots.
 These pots cost $1.03 at K-Mart,on sale.  Two are
bonded together using caulk.  I used caulk that is intended
for kitchen counters, figuring it would be relatively nontoxic.
 One hole is filled in; the other is left open.  The
ollas are buried such that the hole peeks out.

The photo illustrates:

1) on the left: a buried olla with a matching clay cover.
 The cover is intended to be used as a tray to set the pot on,
but here, it is used to cover the hole.  You don’t want to
breed mosquitoes and propagate West Nile virus, after all.  

2) middle, lower-left: one olla with the open hole on top.

3) middle, upper-right: one olla with the occluded hole showing.

4) one of the covers laying on the ground.

5) a buried olla, with the opening showing.  

6) various tomato plants.

7) soaker hose.

Some people connect the ollas to a drip irrigation system.
 This is done by getting corks with holes in them, and
threading tubing from the irrigation system emitters into the corks.

The ollas help to conserve water.  Perhaps more importantly,
they help keep the plants alive.


  1. #1 Willa
    April 14, 2008

    I will be waiting for a tomato and toasted cheese sandwich!

  2. #2 Robin Pratt
    May 16, 2008

    This is great. I have been looking for a way to make one of these and I am now going to! Question, though: How much area can be watered by one of these? If I have a big garden, how many do I need to bury?

    Thanks for the idea,


  3. #3 Joseph j7uy5
    May 17, 2008

    I’ve read that the water spreads out to form a rough sphere twice the diameter of the olla. That assumes a roughly spherical olla, which these are not. They are about six inches across in the horizontal plane. That means that the water probably only goes out about 3 inches.

    I’m sure it depends on the soil type. Sandy soil, the water goes down more; clay soil, it spreads out more.

    The thing is, the plants send their roots toward any water source. So the diffusion is not terribly important.

    We are getting pretty good results with the configuration shown above: four tomato plants per olla; each tomato plant about 12 inches apart.

    I’ve seen photos of ollas that were dug up after the season. They are completely encrusted with roots.

    I’ve been playing with the notion of using drain tile, to make really long olla-like contraptions. I’d run a hose up to the surface to fill it.

  4. #4 richfisher
    June 27, 2008

    Hola, Kitchen Gardeners!

    Great tip , Gracious
    Before burying the water reservoir (Olla) pack the hole with lots of compost or composted manure and the plants roots will find the water that leaks out of your Olla.

    I have planted gourds around a similar buried bucket with holes in it as recomended by a Kitchen Gardener magazine article from a few years ago.
    Worked great and you can add liquid fertilizer to the water that goes into the Olla.

  5. #5 Denise4Peace
    August 19, 2008

    Hey, Joseph…
    Where do you buy drain tiles?
    I’ve been trying to find some in Eugene, Oregon (plumbing shops, home impovement centers) and most folks don’t even know what the are! The guys in the plumbing shops say either they aren’t made any more or they are all plastic.
    I’m embarrassed to admit… now I can’t even remember what was the cool the project that got me started on my search for drain tiles, but I know it was something really good and now there’s the Olla idea, too.
    Any help locating these would be great.
    **Denise (for Peace!)**

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