Clay Pot Irrigation Experiment

After last summer's drought and an gardening season full of teachable moments, I decided to try irrigating with clay pots instead of drip line. This is not a new idea, just the first time I've tried it.

Teachable Moment 2015: Drip line will keep your plants alive but is expensive and is not conducive to easy changes in the garden, like crop rotation. I'd consider using it again to keep permanently placed trees alive, but won't be using it in my main garden anymore.

As an experiment, I put clay pots next to some of my cabbage starts but not others. These are the small, cheap terra cotta pots that everyone has sitting unused in a greenhouse. Filled the hole at the bottom with silicone caulk and placed them in the garden. Despite having a pleasantly rainy spring and consistently damp soil, the differences have been pretty profound. The big ones are next to pots. The small ones are not.



I put pots next to my direct-sown squash plants during 90-degree days and hardly needed to water the seeds to get them started and now only water the pots, not the plants.

My watering is way down, more accurate, and appears to be more effective. And, I am having fewer issues with weeds. Given that the pots are pretty much endlessly reusable, in the future, I'll be planting pots first, then plants around them.

Having just put in drip in my already grown garden I can attest to it not being the easiest method. I have seen the fancy clay pots they sell and have always been curious to try them but found them too expensive especially now knowing if they actually work so thanks for this post.

That said, a few questions

What size pots did you use?
How did you water them and how often
How is burrying the pots less work than using drip?

If you want to try another experiment, take a clay pot, turn it upside down and silicone it on top of another of the same size. Because the top is enclosed except for the small hole that was formerly on the bottom, your evaporation is cut down to a large degree, and you can add twice the amount of water, so you shouldn't have to fill it as often. It also waters deeper in the ground. Drawbacks are using two pots instead of one, and digging a bigger hole to install the pots initially.

I too am very interested in this technique. I find planning the configuration of drip irrigation in beds that will be growing different things in different places at different times seems like it will be far more work, and FAR more expense than necessary. I'm trying to make my garden as drought-proof as possible, but also as low-cost/low-input as possible. So the idea of the buried clay pots is very appealing. I am building my garden on buried wood trenches, so that should help with water retention once they are established, and have soaked up a couple of winter's worth of rain. Plus, I have a collection of pots that were either already here when we bought the place, or I've picked up at the Free Store. So, I'm ready to plant some!

With the buried clay pots, I suppose that moving them around could be more work for those with soil that is difficult to dig. Hopefully you will eventually have lovely soft deep soil, which will make it easier. I would think that using more but smaller pots would work well until the soil is more easily dug. The 'soil' on top of my buried wood beds is basically just two or three feet of mulch (we have no soil), so burying the pots won't be a problem.

I'll have to experiment with the spacing of the pots, to ensure that all the plants are getting their fair share of water. If anyone who has experiences to share concerning this, I look forward to hearing them.

Very timely post, as I, like so many of us, am working toward creating a low-cost, low-input system, low-energy system.

Anyone have any more advice on this topic?

Cheers
Tracy

Keep in mind that this is my first year trying this and the soil in all of my garden areas has been well-charged by rain, so YRMV.

What size pots did you use?

For my greens and brassicas, small ones that I had sitting in a greenhouse.




The broccoli near the pot have headed up much better than the ones without a pot.

I put bigger pots near eggplants and cucumbers and even bigger ones near my tomatoes and big pumpkins.

How did you water them and how often

I fill up a pitcher while waiting for hot water to reach the tap and top them off. During the 90-degree stretch, I topped the small pots off daily. During cooler weather, I fill them up about every third day. The bigger the pot, the longer it can go, at least until the plants get big. This may all change mid-August when the soil isn't charged from rain. You could easily top them off with a hose with a nozzle. The most water I have used so far has been eight gallons. Obviously, it depends on how many pots you have out, weather, etc.

How is burrying the pots less work than using drip?

A few turns of the trowel and they are in. And if I don't like the placement, I can just dig a new hole rather than having to find a goof plug, punch a new emitter, and put in a new emitter. No cracked hose. No emitters where I don't want them. No hoses or hardware. No leaks. And no completely redoing the system the next year. I'm really glad I put in a drip system last year or everything would have died, but I just found the whole process really fussy. During a dry year, I'd definitely do it again for new trees and shrubs. But, the "dig a hole, fill it up" approach seems to be working out better for me. And, for someone looking to get something going on a hugelkultur bed but doesn't want to run line on a bed, I bet this would be a good option to get a plant up and running.

If you want to try another experiment, take a clay pot, turn it upside down and silicone it on top of another of the same size.

That is next! And possibly a gravity-feed system if I want to expand to a bigger area. I'm eyeballing Craigslist for a score of pots. I used up the ones I had sitting around, bought a few more, but am looking for someone looking to unload a bunch.

I can't quite tell from the pics - Do you have the pot buried, and the tray sitting on top as a lid, then you just lift the lid and pour in the water?

Yep! Buried to ground level. The lid is just the tray that comes to fit the pot. Just lift the lid to add water. If I had a ceramic drill bit, I would drill a hole in the lid so rainwater would just flow into the pot.

Brilliant. I love it. I'm doing it! Of course, it just stopped raining, and it's been a pretty moist last week or so - but I know the dry times are coming. Should be a great experiment!

Thanks!

That's the thing. With pretty decent rains and mulch this spring, my soil never seemed to get close to remotely drying out so I was really surprised at the differences!

I'm going to set this up right away - well, as soon as it stops raining - with the pots I have. I will really need some hard evidence to convince the man that all that expensive irrigation stuff isn't necessary. I'm watering the garden by hand this year anyway, and only have the two 4x40' beds right now. But the others are in the works, so I want to have the experiment well underway when the time comes to assess our water needs for the garden.

Keep us posted on how it's going for you, so I'll have a little more 'evidence' to present.

My cabbages have grown up!   The only water I used was the clay pots.  We did have a little bit of extra rain in July, which helped.  The rest of the soil in the beds is pretty dry at this point in August, but the plants have stayed in pretty good shape.  Could they be in slightly better shape if I watered heavily with a hose?  Probably.  But, I used the least amount of water in the garden this year and have had some of the least water-stressed plants because I only had to get out there and water every few days and didn't make too many mistakes.  Hotter, drier weather would have required more watering and could have resulted in more plant stress.  But hey, food from plants that required only a few gallons of water (from me) their entire growing season.   Nature did give a good assist this year, so efforts in the future will vary.    Next year, I will plant the pots first, then seed or transplant around them.  My big mistake was having my cabbage too close together and it got difficult to water without damaging the leaves.

This is cool -- and my wife's a potter, so we could have perfectly tailored pots.

But I wonder: Was there any issue with mosquito larvae in the standing water environment of the pots? We have enough skeeters as it is...

Chip, not that I know of.  I did have some slugs climb through narrow spaces in the pot, which was kind of gross, but with the lids on, I don't think they were attracting mosquitos.  

Brilliant - I am going to do that in my polytunnel next year!!

Currently I water each plant with a plastic bottle half buried in the soil, but with these pots, the flow rate would be slow and steady - much better!

No need to water anything outside in the part of the world though - peeing it down again as I type

L

TO:  K. Putnam
FROM:  Eric Koperek = erickoperek@gmail.com
SUBJECT:  Clay Pot Irrigation
DATE:  PM 2:04 Sunday 21 August 2016
TEXT:

(1)  Clay pot irrigation is an ancient Chinese agricultural technology first written by Sheng-Han in his "Agriculturist Book of China" in the first century before Christ (circa 100 BC).  Chinese farmers used this technique to grow melons in arid and semi-arid regions because the water use efficiency is nearly 100% = almost no water is lost to weeds, waste, runoff, evaporation, or drainage.  Clay pot irrigation is still useful today, especially in places where water is scarce or expensive.  With clay jars large amounts of food can be grown with comparatively little water.  The closest comparable modern irrigation technology is "drip irrigation".

(2)  Space holes 14 feet apart equidistantly, 14 rows x 14 holes in each row = 196 holes per acre.

(3)  Dig holes not less than 5 inches deep and 24 inches diameter.

(4)  Fill holes with 40 pounds of dry manure + 40 pounds topsoil = 80 pounds total WEIGHT.  If you dig a larger hole use the same proportions, 1 : 1 = 50% dried manure + 50% topsoil = 100% by WEIGHT.  Do not measure by volume or the soil mixture will be too heavy and dense.  You want a very high organic matter soil that absorbs water like a sponge.

(5)  Bury a 6 to 8 liter = 1 1/2 gallon to 2 gallon porous UN-GLAZED clay water jar in the center of each planting hole.  Sink the jar so that the rim is level with the soil surface.  Note:  Jar neck should not rise above grade level or much water will be lost to evaporation.

(6)  Fill jar with water all the way up to the rim.  Jar must be completely full = brim full.

(7)  Place a lid or tile over jar mouth to prevent evaporation.

(  Plant 4 melon seeds equidistantly around clay water jar.

(9)  Mulch planting hole with agricultural wastes.  If organic materials are not available use rocks of pebbles to cover soil.  Mulch retards water evaporation from soil.

(10)  Re-fill clay irrigation jars daily.  Fill jars completely = brim full to maintain constant water pressure through ceramic.

(11)  Melon root hairs will cover jar surface absorbing water as it slowly seeps from ceramic.

(12)  You can use larger jars (2 1/2 to 3 1/2 gallons) to irrigate bushes and trees.  This is a great way of growing lemons in the desert.

(13)  To make your own clay water jars mix 25% fine corn meal or similar material with 75% pottery clay = 100% by VOLUME.  When jars are fired cornmeal burns away leaving porous ceramic filled with millions of tiny holes.

(14)  You can fire clay water jars on top of the ground = no kiln required.  Surround jars (top, sides, and bottom) with a 12 inch = 31 centimeter deep layer of wood or dried cow manure cakes.

(15)  Do not disturb jars until embers are completely cool.

(16)  Alternatively, have a local potter make clay water jars for you.

(17)  Key concepts to remember:  Soil must have very high organic matter content to hold sufficient water for plants.  Clay jars must be un-glazed and buried to their rims.  Fill jars to the brim daily.  Always cover jar mouth with a lid or tile to prevent evaporation. Cover soil in planting hole with mulch to prevent evaporation.

ERIC KOPEREK = erickoperek@gmail.com

end comment

Our summer drought broke this afternoon, so I ran out to pick some cherry tomatoes off my one plant before they split with the summer rain.  I pulled a quart off in about a minute.  I've been eating off the one plant all month and there is still quite a bit of partially ripened and green fruit on there.  The soil around the pot has been bone dry for at least a couple of weeks and the only water the plant has had is from the pot, which I have topped off maybe once a week?    Easiest tomatoes I've ever grown.  Great flavor!

Where I live I gave up on watering in favor of making the soil my water tank.
We just don't go without rain often enough to justify having any kind of system.
For you drylanders the combination of drip and olla irrigation has been used to good success.
Essentially the drip lines have an olla sealed to their ends,fed by a bucket in the role of a header tank.

I am wondering if manure tea could be brewed in an open mouthed olla or in the header bucket describe above.
Maybe pee could be added?
Calcium? Epsom salts?