Ollas from start to finish

There are other good sites on the internet (for instance, this one) that describe how to make home-made ollas (which are cheap, high-efficiency garden irrigation devices), but I thought I'd summarize here to make it even simpler and to expand upon the actual use of ollas. 

(1) Materials.  You need common unglazed flower pots, plastic or ceramic scrap pieces, and silicone.  For smaller ollas such as the ones pictured below, you will also benefit from a simple plastic funnel, which will make filling them quicker, but you don't need that until you start to actually use them. 

(2) Construction.  Each olla requires two same-sized un-glazed pots fit mouth-to-mouth with one bottom drain hole plugged.  The smallest pots shown in these pics below were $1.08 apiece, and the larger were $1.98 each at a big-box hardware store.

Aside:  Alternatively, you buy ollas ready-made on the internet, but they are expensive - as of the date of this blog post, about $30 apiece.  Furthermore, the most prominent internet seller has attempted to enforce a trademark claim on the phrase "urban homesteading", even though this term has existed in common American speech for decades.  This is widely regarded as a bad-faith effort on their parts and I, for one, will not patronize their business.

This first batch of our ollas consists of smaller ones to be inserted in our vegetable garden stock tanks.  Depending on how these perform, I may make larger ones and position them next to the root balls of some of my favorite landscape shrubs, which are so hard to keep watered during times of drought.

Note how I've positioned scraps of plastic in the bottom of the front three.
The back three will become their "tops".

Here's a close-up of one of the bottoms,
with the plastic fragment covering the hole.

Here the plastic scrap has been stuck in place over the hole with a gob of silicone caulk.

Next, add silicone all around the edge of the bottom pot. 

Position the "tops" on, and smear the silicone so that it fills in the groove between the two and doesn't stick out too much.  Make sure all the "tops" have the hole left open so that they can be filled with water after being inserted into the ground.
The silicone takes at least 24 hours to fully dry.

 (3) Installation.  Bury each olla such that the soil is flush with the top.

Here again is one of the six-inch ollas, which seems to be a pretty good size for positioning between this broccoli and its neighboring cauliflower plant.

Simply dig a hole the same depth as the olla, and then bury it.

Here's the buried olla which I re-surrounded with landscape rock scraps (these rocks are intended to slow evaporation by limiting the amount of soil surface).  I paid two bucks for this funnel and I think I got ripped off.  This funnel has a fancy rubber base.  Any old small plastic funnel will do.

Here's the olla full of precious water, ready to do its job!

Here you see two buried ollas flanking the cauliflower. 
My gardens are round, but if you have conventional rectangular gardens, you could put an olla in between each plant in the rows, or you could install them between two parallel rows so that plants on either side could access the moisture.

DO NOT use wine corks
to plug the top hole between fillings!
Initially I thought this was a great idea, for keeping out dirt and mosquitoes.
But the cork makes such a tight seal that it forms a vacuum and then the water can't seep out of the olla.  I learned this by experience. 

Maybe just use a chip of rock to cover the hole.
Or break a tree branch and stick that in (maybe even making a sculpture statement with it).  Just don't seal the hole entirely.

I'll update this post further when I have more to say about their efficacy in longer-term use.  So far (with them being in the ground about two days) I've noticed that my veggie starts are no longer wilting between waterings (to be safe, I'm still watering by hand despite the fact that it's possible that all the water the plants need might be deliverable via the ollas).  The ollas are currently discharging at about one quarter of their volume per day, with the smaller ones discharging faster than the larger ones.  As the plants get more established and I get more brave, I'll gradually increase the time between regular waterings, just to see if the ollas can pick up the slack by increasing their discharge rate.