I was recently perusing one of my favorite websites, Little Homestead in the City, and came across a blog post about ollas, or clay pot irrigation. The whole concept, which has evidently been around for a few thousand years (leave it to me to just be finding out about this), is fascinating.
The idea is that a porous clay pot is planted in the ground or raised bed and filled with water. Plants are planted around the pot and the roots grow to the source of water. The water wicks out of the pot through the pores and waters the plants directly to the root system. A rock (or something like a scrap piece of broken pot) is placed over the hole to keep mosquitoes out. The pot is refilled as needed depending on temperatures, rainfall, etc.
According to the Permaculture Research Institute of Australia, there are a lot of good things about the method including 50-70% water savings, guards against water stress, does not over irrigate, less frequent watering is required, less weeding since weeds do not prosper as the soil surface remains dry throughout the growing season (interesting!), saves on fertilizer if it is applied as part of the water used to fill the pots (can you put liquid worm fertilizer in there? must research this!), the soil of the seedbed does not get sealed due to water impact but remains loose and well aerated, and last but not least, clay pots can be installed on undulating ground where surface water runoff might be a problem.
The Aussies also site some disadvantages such as potential for winter breakage if left in the ground in areas with a winter freeze – definitely a possibility here in Oklahoma and prolonged use is likely to decrease porosity of the clay pot if used in heavy soil.
Here are a couple of very helpful charts that were on the Australian site.
Sounds to me like the pros outweigh the cons. As much as I would LOVE to buy the cute ollas found at Peddler’s Wagon, they are a bit out of my price range. I have three raised bed and will need 4-5 for each. So after a search for DIY ollas, I made a trip to my local Home Depot for pots. Let’s just say, I’ll be buying my next round at a local garden shop where I found them the next day for about 1/2 the price! Here is what I bought for about $45.
Standard UNGLAZED clay pots, saucers, silicone and white paint. The paint is to seal the part of the pot that sticks up out of the ground to keep water from wicking out the top. That was a tip I got from someone’s blog that said they learned the hard way. Sounds like me.
They were not cheap. Each pot was $4, saucers were $3. But I figure if I can get 5 years use out of each pot and with money (and heat stroke) saved from reduced watering, the upfront investment will be worth it. I also discovered a couple of used pots in the garage that I can clean and use. One thing to watch out for when buying the pots: I found that a lot of the saucers had what appeared to be hairline cracks and some of the pots did, too. Don’t know how that would affect the process or the strength of the pot, but just kept looking until I found five pots with no cracks. Anyway, if I’m paying four bucks apiece, they need to be intact, thank you very much.
The first step is to seal the saucer and pot together to make one unit. It takes one bead of silicone on the lip of the pot, squish down, and then a bead around the seam on the outside. Let dry according to the directions on the silicone. Mine said 12 hours which was overnight and then some.
It’s not pretty but this part will be underground. Next came a leakage test. I didn’t do the test on each pot. I figured if one sealed, they all did. Hope I’m right.
Next I painted about 2″ down from the top on each pot as well as the top (which of course is really the bottom of the pot). The pots will be planted with the saucer down and water filled through the hole.
You can see the water wicking through the sides of my test pot. Pretty cool.
So, this is as far as I’ve gotten. The weather has been cold and cloudy and the weatherman says we may have one more overnight freeze this week. I should have already had my onions and lettuce and spinach out, but I’m always slow getting started in the spring. Hopefully, I’ll be able to get the pots in the ground Thursday this week and can show you Part 2.
Until then, keep it simple, ya’ll.