Clay pot worm farming

Sort of.

My garden has suffered long time from a shallow habitation of  earth worms. Sandy soil. Absence of biomass. Limited irrigation...

It wasn't very worm friendly.

 No matter how much compostable material I'd thrown at the garden beds every time I went on a worm hunt the critters were hard to come by. 

Since I am of the school that celebrates busy worms as the epitome of good gardening DIY you can imagine my frustration. Here I was preparing the beds for sleepovers and I wasn't attracting  guests.

But hey! today I was in for a surprise. 

I was replacing my wine cooler clay pots that I use for irrigation with my preferred 22 cm terracotta pots and every time I pulled up an embedded pot, the hole was alive with earth worms. 

I had guests. Finally. Despite the conditions

This is a major milestone both for my garden and terracotta pot irrigation. The worms appreciate the moisture in the neighborhood of each buried pot. Given that we have had hardly any rain, face  drought conditions with the persistent strong dry winds and despite my water usage being halved -- you can imagine how keen I am about this result. 

Worms. Happy worms. Big fat active wriggling worms. Despite the dry conditions.

These pots -- the 'wine cooler' ones -- have been embedded for some time and this fact suggests that terracotta pot irrigation takes a while to consolidate.What works may need time to kick in.

I suspect this isn't simply about waiting for the worms to move in. Soil gotta change. Plants gotta decide where to send their roots. Osmotic pathways adapt. Soil chemistry alters.

We're talking a few gardening months....

I suspect that the ecology 'of the terracotta pot' must also prove itself by being reliable -- ergo that god (ie: I) keeps topping up the water level. Plants (and worms) want to be confident that there's always a good chance that a refreshing drink can be  had at the neighborhood terracotta bar.

My view is that without the pots doing their magical best I would not be harvesting as I am now doing as the conditions have been so brutal these last 6 months. 

To have worms! Well that's  icing on the mud cake.

Of related interest:

"For irrigation purposes, it is important to remember water is absorbed and moves slowly through clay soils, but once wet, they retain significant amounts of moisture. Water is absorbed and moves quickly through sandy soils, but they retain very little. This means water applied quickly to clay soil has a tendency to run off rather than move into the soil. Therefore, when irrigating clay soils, water should be applied slowly over a long period but then the site may not need irrigation for several days. Irrigation on sandy soils should be applied quickly but for short periods. Irrigation times on sandy sites should be shorter, otherwise water moves beyond the root zone, becoming unavailable to the plant and contributing to soil leaching. For efficient water use under certain weather conditions, sandy sites may need daily irrigation for short periods. Clay soils have greater capillary (sideways and upward) movement than do sandy soils  Quick water application on sandy soils will contribute to a broader wetting area, providing more soil volume for roots to exploit."  -- Source:Soil type influences irrigation strategy

Gone Potty II : irrigating with terracotta pots

The terracotta  pots I've buried in the garden beds have proven very effective thus far so I'm getting more. 

• See my earlier post: Gone Potty irrigating with terracotta pots and hand watering 

• and note the method --Buried Clay Pot Irrigation Action Sheet (good summary of the DIY)

A lot of wetpot/olla literature suggests you extend the height of the pot in order to bury it deeper. Indeed many are thrown on a pottery wheel as an urn or carafe shape. But looking at the dampness these pots create extending from their perimeter I'm thinking that the diameter of the pot may also offer its own useful seepage dynamic.

A wider pot makes a bigger pond and the water spreads laterally and below as it seeps trough the terracotta clay. This means that I can plant around the edge and these plants will root and drink both from the sides and below the pot (so long as the soil isn't too compressed or impacted).

In my sandy soil this makes a lot of sense as the deeper you go the more sterile is the 'soil'. Similarly, the shallower the pot the less disturbance and compression there is to the underlying soil structure and the easier it will be to lift up and move around (if I decide to).

I've also learnt that pots with narrow openings -- such as urns and terracotta wine coolers -- are much harder to fill by hand hose than than broad ones. It takes longer to target the lip.

The only challenge is evaporation. As I said in the earlier post, I'm using tiles with a glossy white surface as lids. Light coloured dinner plates would also work.... Now if the seal of the lid is firm enough, the cooling effect of the overhang should work against easy evaporation. And as the seedlings -- planted around the pot -- grow they will serve to shade the terracotta underneath.

If I think that the tiles or the dinner plates aren't solid or thick enough to insulate the pot underneath (or aren't heavy enough to withstand animal investigations) I'll simply glue two tiles or two dinner plates together in order to thicken these lids and make them heavier.

Dinner plates and old tiles are a dime a dozen...and the irony is that the pots I'm buying are cheaper than the terracotta saucers that are made and sold to go with them. And terracotta top -- as the olla literature suggests -- needs to be painted in white in order to reflect the heat of the sun off its surface.

Now if you are into Pique Assiette (broken pottery)mosaic or any mosaic form you'll note the decorative potential offered by these pot lids. You could even set little animal figures atop of them and they'd work as handles!

In reviewing the literature online the arguments in favour of clay pots are strong. Terracotta pitcher irrigation has been shown, in one study,  to save 98.7 percent of water used in sandy loam soils.

That's the kind of  dirty talk  I like.

For small garden plots, sandy soils, limited water resources, dry conditions and lazy gardening this very simple technology ticks a lot of boxes. 

In my setup I'm using a lot of mulch so I'm very subterranium in habit. My major concern -- given the broad lip on my pots -- is evaporation. But today I took the temperature of the water in a couple of pots in full sun and under their lids it remained within a stable range. The mulch atop the soil and the soil itself insulates the pots to create a sort of cellar effect. 

In my garden beds there is  a lot of 'stuff'. Branches. Rolled up newspaper. Cardboard. Nonetheless I fine the pots settle in soon enough among all this detritus and  get to work. However, I'm sure the process of embedding will take  time and as the literature on porous hose irrigation suggests, the soil and plant need time to adapt to any novel hydraulics. 

Unknown is the rate the water will permeate through the terracotta walls. The pots are 'fresh'.  As far as I know they haven't been coated with sealants. When I tested them for any leakage after I plugged the original drainage holes, they sweated the full depth of the water I had poured into them.

Here's a tip: when testing your pots for leakage fill them to the brim as that's your top pressure point.

These pots sweat, I gather, because  gravity forces water through the porous clay walls. Once the water is in the soil,and it's damp,  other processes take over such as osmosis. How far the irrigant will travel from the pot is gonna depend on my soils and other factors I don't as yet know about. But we do know that distance is influenced by components other than sand (such as clay and humus content).

How long it will take any pot to empty is another variable I've yet to  determine. This is, of course, relevant to how often I'd need to top them up. So what's my routine likely to be?

I may also need to relocate some pots and bring them closer together if the wet patches aren't big enough. How far the wet front extends is hard to determine from the literature I've read because there are so many variables. A Leaky hose systems claims that the method will irrigate up to 1.8 metres each side of hose. But some of the terracotta pot research offer very conservative estimates in way of wet front. But pot volume is sure to be  a major determinant as to wetting distance and wetting rate.

This research is interesting:Even small pots can maintain a wet front 60 cms from the pot for a period of 10 days.

Source:

Click on image to enlarge view.

Addendum:Monitoring my pots I estimate -- in our current very warm -- >25 degrees centigrade -- temperatures  -- that they sweat at the rate of 300-500 ml per day. Given that each pot's capacity is 2.5 litres, the formula is one pot full of water will irrigate for 5 days. But then that doesn't mean that it will actually take 5 days to empty in situ or that the wetting effect only lasts 5 days (according to the research cited above). 

Gone potty: irrigating with terracotta pots and hand watering

My many experiments in irrigating my garden  are proving fruitful. 

When I say 'irrigating' I mean keeping the water up to vegetables so that they don't die.

I'm not asking much.

Pursuant of that I've engineered a lot of  creative use of mulch.  So now -- even though we have seen so little rain for the past two dry months -- I'm still harvesting vegetables.

This year I have been fortunate in that my supply of grass clippings has been good and the garden never ran out of a top blanket of the stuff.

The grass later breaks down and creates and enriches my soil...

Combine that with my heavy papering and burying of branches earlier in the year --mulching with anything I could get -- and I've been able to hold onto more H2O than in  past dry spells.

Nonetheless, the garden is still thirsty. 

I have a Leeaky hose system embedded as my primary irrigation network but after using it occasionally for the past two years  I'm finding that the method doesn't suit my sandy soil nor my erratic lifestyle.  I may be able to wet soil when the system is turned on and  'leaking' into the beds -- but when it's not -- and  my system isn't in routine use --  the beds dry out and the plants wilt.

So I've tended to rely on hand watering especially as by visiting each plant with a douse from the hose I get to assess its state of health.  

I like hand watering. It's my  commune-with-nature moment almost on a daily basis. 

Clay Pottery

For some of  those places I didn't have the Leeaky system installed I embedded terracotta pots ( I used wine coolers I bought cheap at Op shops). 

Then a few months back, as an experiment,  I moved my coolers/pots to four of  my primary beds, placed them closer together and made sure I kept them topped up with water. 

I also stopped using  the Leeaky system to irrigate these beds.I only hand watered them as required and topped up the pots.

The results were impressive. Plant growth   was better in these pot watered beds than in others.

If you do your homework, the stats for  Unglazed Pot Irrigation are impressive. Constant seepage with water savings of 50-70% is a feasible option.

So with that experience behind me, I've decided to convert my garden to clay pot irrigation.

Going Potty

From  one of the major hardware chains I purchased 19 cm terracotta pots for $2 each. I plugged the drainage holes by gluing tile offcuts   to the pot base. At the local tip I  got  white tiles to sit across the pot rim. (My wife does mosaics and there are always plenty of tiles to hand so we're a tile-acquisitive household).

The whiteness of the tile gloss reflects heat away from the pot surface and the slight over -hang shades the pot and soil underneath. Tiles are also heavier than plates and bigger tiles are more difficult for crows and other inquisitive or cumbersome critters to shift to the side or flip.

There are any number of online DIY methods to create these 'Ollas' but I've opted with  the simple + easy + cheap. 

Each pot holds 2.5 litres of water which is a generous aquatic reserve every few centimetres. While there is literature on how best to distance the pots from one another -- I've opted to position and bury by experimentation and impulse. The pots are so cheap to buy and adapt to irrigation purposes that I should be able to saturate my beds as I see fit. They're also  like caravans: you can move 'em about the countryside to different parks.

Remember I like hand watering so I don't mind the business of  having to top up 30, 40 or whatever number of  pots as a gardening task. And by hand watering I'm also very conscious of how much water I'm using to keep the garden productive.

Solar Irrigation Experiments

I've managed to build up my supply of plastic bottles enough to seriously explore solar irrigation .

I've devoted one bed to the experiment, so that these solar 'greenhouses' are the only form of irrigation it gets.

While I appreciate the way I can look at these chambers and see the condensation forming on the inside of the plastic bottles -- I'm not convinced that the water condensed is enough to keep my plants sustained. 

We'll see....

Nonetheless what's clear  so far:

• the irrigation is constant. The system works 24/7 -- ie: even at night 
• set up is so easy and ideal for planting out seedlings.
• unlike terracotta pot irrigation, monitoring is easy and there is very little disturbance to the soil when you install the rigs
• less water is used than with the terracotta pot option. 
• Solar irrigation is easy. Terracotta pots are  a pain to service.

If the setup works -- and my plants do indeed get enough water for healthy growth then this would have to be the most efficient irrigation --most water saving -- delivery system imaginable. When you consider that water quality doesn't matter -- grey water, sea water, whatever water -- the potential environmental advantages would be quite extraordinary.

Unfortunately plastic goes brittle in  sunshine and the bottles will eventually need replacing. However, despite being plastic, these little condensing engines don't look ugly among the plants. 

I am reminded of the old nursery rythme:

Mary, Mary, quite contrary
How does your garden grow?
With silver bells and cockleshells
And pretty maids all in a row.

"With glasshouse bells and cockleshells..."

---

 

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