Monday, February 29, 2016

All About Ollas: The Water Saving Wonders for Gardeners

You all know I love using ollas in my garden, right? Which is why I was so surprised when I looked back over my old blogs and realized how many gaps there were in my posts. I've learned so many important things about ollas that I never passed that onto you! Shame on me!

So even though I've talked about this topic quite a bit over the past couple of years, I think it's time for me to start from square one and really try to cover the topic from top to bottom. For those of you who are new, I recommend reading on, because ollas are awesome. For those of you who already know about ollas, I recommend reading anyway. Maybe you'll pick up some new tips. :)

What is an Olla Anyway? 

Let's start with the basics: what are ollas? Ollas are unglazed pots that you can use for irrigation. They come in all shapes and sizes, but the ones I use look like this:

Ain't she a beauty? 

The concept behind ollas is simple: You bury the ollas in the ground with the neck sticking out above the soil line, bury your plants around the ollas, and then fill the ollas with water. When you're done, your garden might look something like this:

The water inside the ollas will slowly seep out through the ceramic walls of the pots, giving the plants exactly as much water as they need--not too much, not too little. In other words, ollas are the Baby Bear of watering techniques: just right. All you have to do is keep the ollas full of water and your plants will take what they need.

Watch out though! If you plant too many plants around the olla, finding the olla later to refill it will be like playing Where's Waldo

As someone living in drought-prone area, what I love about ollas is that practically no water is lost to evaporation. Ollas are just about the most water efficient irrigation option there is because the top of the olla is covered and the irrigation all happens below ground level--no water evaporates in the air. Ollas are far more efficient than hand watering. They are even more efficient than drip irrigation, which people just rave about when it comes to saving water. 

Will My Plants Grow As Well with Ollas? 

I can't tell you for sure that all of your plants will do well with ollas, but I can tell you that I have had really good luck with them in my vegetable garden. I even did some side-by-side tests of ollas vs. drip irrigation, and most of my plants loved 'em. I've read that plants do well with ollas because: 
  1. The ollas deliver just the right amount of water--not too much, not too little.
  2. The clay in the pots actually delivers a few extra "bonus" minerals to the plants.
  3. If you happen to use rain water in the ollas (like I do), the water is purer than the water delivered via a standard drip irrigation system. (This might not be true in your area, but here in Gilbert, the municipal water is a little salty.)

I've got the saltwater, now if I just had the beach to with it

How Close Do Plants Need to Be to the Olla? 

As best as I can tell, the thicker your soil, the closer your plants need to be to the olla. (It's easier for water to soak through looser soil.) But that's not a very exact, is it? The way you can tell precisely how close your plants should be to your olla is simply to bury your olla, fill it up with water, and let it sit for a day before doing any planting. When you come back, you'll find a damp area around the olla. That's where you can plant.

Are There Any Tricks to Starting Seeds with Ollas? 

Hand-water any seeds that you plant around ollas until they sprout. (Seeds can't really take advantage of the damp soil until they actually develop roots.)

How Often Do You Need to Fill the Ollas? 

The interval between refills varies a lot. I've gone anywhere from every two days in the summer to once a week in the winter. Other factors can impact how often you need to refill your ollas too. For instance, I try to keep them topped up for seedlings, since their roots won't be long enough to reach the bottom of levels of the ollas. Non-intuitively, I also sometimes find that ollas need to be refilled less often when plants get very mature. This is because the plants' roots have adhered so completely around the ollas, no water is getting lost in the soil--it all goes straight to the roots.

Honestly, this is one of the biggest downsides of ollas--constantly refilling them. If you're busy, traveling, or just kind of lazy (all of which apply to me at times), refilling ollas on such a regular basis can be a real drag. Happily, David Bainbridge's new book, Gardening with Less Water gave me a great idea for how to fix that--create a system where the ollas fill themselves. My husband and I just finished putting together a system where we're feeding water into the ollas using tubes attached to rain tanks. (But that's another post.)

How Much Do Ollas Cost? 

In my neck of the woods, a two gallon olla costs about $34. I think most people would consider that pretty pricey. (Of course, if you compare that to installing a drip system attached to a controller, it's cheap, but I don't think that's what most people are comparing it to.) Personally, I think it's worth it, but I know most people aren't willing to shell out that type of cash. 

Money doesn't grow on trees you know!
(Particularly if you haven't saved enough water yet to grow the tree.) 

Can You Make Your Own Olla? 

Yes! You can make your own olla. There are tons of "how-to" blogs about it all over the internet. Before you go make your own though, let me tell you a few things I've learned: 

  • When I've done a side-by-side test of a DIY olla vs. the real thing, my plants did better with the real thing. I'm not 100% sure why, but I have a good guess: my test was conducted in hard conditions--it was an Arizona summer and I was growing the plants in (amended) native soil (i.e., clay). The DIY olla was probably at least slightly less porous than the real thing, and just could not deliver water as well. As a result, the plants getting water from the DIY olla suffered. 
  • Having said that, I've learned since that's there are ways to test for porosity in unglazed pots. Just spray them with water and make sure that they immediately get wet. Or dunk them in water and make sure they get uniformly wet. If there are any dry spots, it's not suitable for an olla. 
  • Another thing I've learned since writing my original blog about creating your own ollas is that it's totally not necessary to glue to ollas together (like most tutorials recommend). Instead, just find a cork, plug the bottom of a pot, and use that as an olla. Place a saucer on top for the opening. It makes it a whole heckuva lot easier to get the water in! 

Do Ollas Require Maintenance? 

A little. I use a stiff brush to clean mine between seasons. Also, it's a good idea to soak them every now and again in a combination of vinegar and water. (For instance, I soaked mine in vinegar and water after I realized my soil was diseased.)

Anything Else I Should Know? 

What?!? Aren't you bored yet? I think I hit the biggies, but if you're just dying to learn more, here's what I recommend: 


Raven Kirkland said...

Would you by chance have instructions or know someone who does have instructions to build a continuous feed olla ball irrigation system? The ollas would be connected to a water supply line which would be connected to a food grade water barrel. The water barrel would be fed by city water and would have a swamp cooler float inside so that a constant level of water can be maintained within the barrel. I want to use a system like this to water my garden here in NM. I often travel for work so it is hard to keep my garden alive without consistent watering. I would much rather use Ollas than a water drip system. Thanks. Marcella

claudette said...

Hi Raven. I recently set up something similar to this for reasons similar to yours. I hope to write a post about it soon. If you're in a rush, I recommend getting "Garedening with Less Water" by David Bainbridge. It won't have the exact instructions you are looking for, but it will get you a lot of the way there. You could also try olla balls (I haven't tried them myself, but I've heard good things) attached to an irrigation system: Good luck!