Still more on terracotta pot irrigation...

Having got into some online chats about clay pot irrigation I thought I'd import dome of my comments...

I just bought another 10 pots from Masters at $3 each and put them to irrigation use.I now garden with over  60 pots  in situ. Today I got another batch of stoneware dinner plate lids for 20 cents each.
In the DIY adaption build I recommend grout rather than glues as generally a quick coating of the base is foolproof with grout. Glueing can be fickle. Just tape over the pot's drainage hole on the outside with masking or some other tape.
After using various irrigation approaches, buried hose driven, I'm absolutely smitten with clay pot style. Cut my water use in more than half. Change the whole nature of my garden and bought in worm colonisers.
On the question of terracotta wine coolers as irrigators -- I have to say that while some work, others don't...sweat. So stay away from wine coolers if you can. They aren't reliable.  The Master's pots -- a 19 to 21 cm rim (holding approx 2-2.5 litres) -- will sweat to effect and I've only had two (out of all of mine) that don't.
Given that an Olla --sold here as Wetpots -- costs $189 for a 10 pot watering system...price difference  do kick in. But the system seems to me to be a variation of Leeaky hose style approaches. 
With the single pots I can move them around as required. The shape of my garden doesn't matter nor does the location of any plant.
Have pot/Will travel.
All I need is a gardening hose to follow them.
Terracotta pot irrigation needs time to settle in. The soil has to synchronise. My pots empty on a 3-4 day cycle on sandy loam. In clay soil I suspect it would be a slower rate of emptying.  If you wanted to use them inside other pots, they'd work but a wicking bed approach would be more efficient.
In Summer white plates -- or white saucers --are preferable as lids because the bases supplied with some coolers get very hot and increase evaporation. But even if the coolers don't sweat they will nonetheless condense coolness and some moisture along their sides.
The Wine Cooler bases as lids are also more easily  circumvented by Cane Toads and mosquitoes.
Presently I'm exploring what planting distance from each pot suits various seedling species. 

Perennials have plenty of growing time to creep some distance.In my soil I'm usually distancing each pot by 1.3-1.6 metres from each other when placed in standard beds.
Elsewhere I embed a pot often alongside  new tree plantings. The wine coolers are excellent for that option.
But the synchronicity thing is important. Once the soil and plants have confidence that the pot is there and can be relied on to do its irrigating the whole soil neighborhood settles into remake. Osmosis pathways change. Soil texture alters. The change over a 4 month period is remarkable.. in my garden it was miraculous. Worms move into the pots' surrounds to survive the Summer heat and any dry periods.Biota activity quickens.
I'm  now  experimenting with planting patterns and suspect normal rectangular beds may be  a complication. As an exercise, I've built up some large mounds for tuber planting  and inserted pots -- wine coolers actually -- in the middle of each mound, like a crater in a volcano..but with a lid. That way the whole mound is constantly irrigated.
But the logic makes  a grand hypothesis:large conical mounds with terracotta pot craters....
As for watering-- I readily know how much water it takes to irrigate the garden so I am so considerate of my water usage.Other systems are not as easily monitored.So if I have 50 pots and each holds approx 2.5 litres I know that my water usage will be around 125-150 litres if I fill all of them up. I realized today that if I go around first and remove the lids, then do my watering circuit, I use less water than if I uncovered, watered and re-covered each pot while at each station.
Reason:The time it takes to lift the top plate and replace it given that I don't use a nozzle.I do often hose the surrounding plants on a bed, but if I'm just moving from station to station without having to bend down and play with lids -- I'm gonna be more water efficient.

What these 'plate lids' need is a long handle enabling a no bend approach. Like: _I_

Also over time, you see, plants grow over and around the plate lids and it can take some foraging to locate and lift, then replace, a lid.  So think of the tasks the hands may need to perform given that one is carrying a running hose. 

You could engineer up and run irrigation tubing into each pot as per the Olla habits but when  I fill manually I'm savvy with the water levels, water requirements, local vegetative health & growth, soil conditions...etc.

I'm 'communing' with Nature...

In dry and hot weather I hose my garden daily as a supplement because its base is so sandy. But I check the beds and handle the soil for indications of moisture content before hosing.
The other advantage per the 'effort' quotient with terracotta pots, is that they target irrigation to what you want to grow rather than what you don't (like weeds) ...and less for the more self sufficient  such as perennials.


Aside from the top/plate lifting complication I'm delighted with the system.
I happen to have Leeaky Hose Irrigation installed in my beds. Leeaky --SubSurface drip irrigation -- is well respected as a water saving irrigation system.
Leeaky Hose takes advantage of the fact that water acts as its own conductor. It is designed so that water ‘sweats’ through its walls at a controlled rate over long distances at low water flow. At pressures of 4psi or below the hose will deliver moisture to the surrounding soil through capillary action. As a rough guide, Leeaky Hose releases water below ground at around 2 litres per metre per hour.
...and I don't use it.
I stopped using it because:
  • I had sandy soil and any irrigation session -- even over a few hours -- meant that the water soon dissipated in my sandy soil.
  • I was 'over' watering one day and drying out on others.
  • I'd turn the tap on (even just a wee bit) to run the system (and employ gravity) then forget about turning it off so I wasted water.(My tank system did not suit timers).Even if I used barrels as gravity feeds--I still had to fill the barrels. 
  • The pressure wasn't constant for the whole tubular network and I could never actually tell how much water entered the system and how much water got where as all the activity was underground. With pots all you need do is look at the water level..and maybe feel the soil near bye.
  • Once installed and hooked up, the tubing is hard to move around to new places.You have joins and lengths to consider.
With the pots I'm in control and I'm watering for 3-4 days rather than for 3-4 or more hours.
The research figures suggest that pots are as efficient -- or almost as efficient -- as wiking beds.
I've got more  info here on my site about my experience with terracotta pot irrigation...
But it has meant a massive change to the garden. Massive. It's also changed my gardening habits -- my stewardship -- as these pots and a garden hose are my primary tools. They serve as a sort of fulcrum anchoring everything else--the life force.
The literature (primarily by Indian horticultural researchers) does review how far the water travels relative to pot volume and soil type. See example. 
However, while I've changed my soil  sand by adding a lot of organic matter --thus increasing its water holding capacity, I suspect that the pots and the surrounding soil (and its biota) have taken time to consolidate the marriage. Like the way bushland relates to a stream.
It's not like irrigation flooding but constancy.
This 'could' mean that I'm promoting more fungal problems -- or , at least , more fungal problems closer to the pots than further away. But, for now, I can't answer that question because I cannot see a clear pattern emerging. 
And the worms love em heaps...lift a pot, even on the hottest Summer day, and you'll get a wriggle carnival. Before I hardly got a worm anywhere -- despite inoculation. My beds are now worm farms. This means that they are doing a lot of my work for me,  ferrying nutrients about and spreading the good stuff from my Honey Holes.
Now if I was designing my garden afresh I'd start with pot placement and construct the garden around them. There's something to be said for circular beds, or at least beds like this

-- indeed I am experimenting with growing tubers that way. Since I used to garden inside car tires the circle utility makes sense to me. You'd grow the annuals in the circle , close to the clay pot, and perennials (or slow growing annuals)  in the 'isthmus' between circles. The perennials' roots would have plenty of time to travel the distance to a wetter area.


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