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Clay Pot Irrigation: no more flying saucer parking lot.

There I was commuting on the train heading south towards the CBD when I had one of those moments.

My 'thingness' came upon me and I had a flash of transcendence.

"What, if," thought I, "I used shade cloth instead of plates atop my irrigating clay pots?"

And voila...!

I got myself home. Cut me some circles of high level shade cloth and pegged the 'lids' atop my clay pots.

No more flying saucers!

No more having to lift the stone ware plates  to fill the pots or to  monitor their contents.

When hand watering, all I need do is squirt water into the depression to fill my terracotta pots to the brim.

Easy peasey.Quick as a flash.

Aside from the labour involved in removing eighty -- yes 80! -- lids to irrigate my whole garden, it always concerned me that mosquitoes could sneak under my lids to breed. I'd get snails and slugs too inhabiting these chambers because the plates were never snug enough.

With adjustments as the cloth settles I can now look forward to keeping  these beasties out.

While I decided on simple clothes pegs to attach the shade cloth to the pot rim,I reckon the grip is strong enough to support a cane toad wetting its rear end over night.

Any rainfall: straight into the pot.

Morning dew: into the pot. 

My one trade off is evaporation but then research suggests that shade cloth spread over water storages can reduce evaporation by up to 90%.

Given that the zone immediately around each pot is often the most verdant anyway, the plants fed by the pots will supply even more shade.

Given that the system is primarily gravity fed , the higher the level of the water in each pot -- the further the moisture will spread and irrigate.Since my habit was to refill the pots when they emptied, I can now simply top up the water level of each pot as I hose the garden. 

I expect the shade cloth to mould itself to the shape of the pots as heat and use bears down upon the folds.

My irrigation time has been  cut in half. I can even fill pots 2-3 metres away from where I stand.

Is there a downside? So far, none found.


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Comment by Dave Riley on August 16, 2016 at 23:43

AS I pointed out HERE , I added a doily layer to the clay pot covering. Since then I've added another doily. So the pots are now shaded by one 'tablecloth' shade cloth layer and two shade cloth doilies.

Because watering is so much easier, the garden -- and my interaction with it -- has taken off.

Since I can so easily keep the water volume in the clay pots elevated, the system works so much better. Water volume (under pressure of gravity) is one of the main drivers of fluid dispersal. 

I no longer have to check the volume of water in each pot because I can hear the sound of the chambers as I squirt water into them. Just like pouring water into a kettle. While I may wait until I see water pool atop of the 'doily' , the sound of the clay pot filling also flags the volume rise.

Indeed, since I want to start emptying last Summer's pool, and recycle the water,  the 21 cm diameter of the larger pots are easily filled from a 10 litre bucket. If I run out of tank water, I have that reserve supply to harvest.

Furthermore, the three layers of shading cloth are not conducive to much evaporation. I may still add another layer if the permeability is enough not to obstruct the stream from the hand held hose.As it is the water can get in(via hose, rain or dew), the sun is shaded to a very very dull twilight (I've checked); mosquitoes, snails, cane toads and slugs are locked out...and the only hiccup has been that one of the dogs stood on a pot cover one night while chasing a night creature around the pond.

Checking today, it's clear that the soil wetting arc  is much larger under this new system and I can plant vulnerable seedlings at farther distances from the clay pots. The mounds are cooler and the bullseye effect with the bright red fabric ensures I can target the pot regardless of the surrounding verdancy.

We have started to experiment with this rig at the school garden.There the children , while keen, are unskilled at hand watering. But if we can teach them to fill shaded clay  pots we'll save water and ensure better garden irrigation. We also reduce the watering burden.

With clay pots of 2.5 litres in volume, each pot fill will water its precinct for 3-4 days -- although less efficiently as the water volume drops. That means that the more frequently the pots are topped up, the more water is pushed out into the soil in any 24 hour period. 

However, any plant irrigated by a pot will, as it grows, direct its root mat 'upstream' towards the source of the water --especially as the moistened zone retreats. This is partly why clay pots are ideal for use in growing annuals. Perennials tend to embrace and strangle the pots, whereas the flexibility of a bed of annuals, enhances the collective underground environment.

Here's the working hypothesis schematically illustrated.

The mounds over time become a mesh of roots and earthworms. Despite the close plantings, the surface area is increased by  50-70% because of the contour of the mounds. I'm experimenting with planting root veg, tubers, greens and such  on the same mound with staggered harvests in mind.

It's amazing how many plants can co-exit on the one hillside.In fact, the more various, the merrier.

The only draw back so far discovered is that the mounded earth heats up more than flat soil. Ok in the cooler months, but a problem in Summer. However, if the mounds are shaded and mulched -- and the water is kept up -- either through  filling the pots or precipitation -- the mounds are cooled.Indeed the close plantings shade the mound and along with the in situ pots, mulch and ecology, each mound fosters its own microclimate which can vary according to the nature of the soil it is built with. Younger mounds also  heat up faster --and dry out more quickly -- than older ones.

It takes at least a year for a mound to consolidate its habitat. 

As the mounds settle -- they settle rather than erode -- water filtering through the sand granules is slowed and as the many plant roots merge with the mound, the water holding capacity of the soil is enhanced just as the plants growing on the mound slope slows run off and supports the blanketing absorbency of the mulch layer.

Comment by Dave Riley on August 1, 2016 at 23:19

I finally finished blanketing all my pots with shade cloth. Over time I'll need to adjust the covers  so they sit neatly in every instance. 

I think the skirt overhang needs to be buried so that you can plant flush up to the pots and that no creatures -- like cane toads (as I discovered today) -- move in below any awning overhang.  You may need to vary the peg numbers in some cases and deploy a tuck so that the cloth sits firmly on the pot rim. 

Just on the logic of the overall:

  • clay pots can be buried anywhere you choose to irrigate  and left in place permanently or temporarily (such as next to a newly planted sapling).
  • clay pots can be filled  as required: you don't have to irrigate a whole area as you do with underground hose systems or ollas with narrow lips.It isn't all-or-nothing irrigation. Watering -- and water saving --is completely in your manual control.That means no turning on the tap and forgetting that it's on. (Been there/done that plenty).
  • you can choose which pots to fill according to your assessment of  plant growth.
  • however, since the system is driven by gravity, the more water in the pot -- the further the dispersal of the moisture.
  • but damp begats damp (Hygroscopy)-- and if you wet the surrounding soil the seepage pathway is enhanced as it is by morning dew or rainfall.
  • pots left in situ over a long period of time foster their own local ecology and wee micro climate. This is enhanced by the number of worms who will move into the zone wetted by the pots and the concentration of worm castings in the area. remember: worm castings can contain 40% more humus than the top 23 cm of soil in which the worm is living (SOURCE).
  • it may take upwards of a year for buried clay pots to consolidate the ecology of their zone of influence.Like bush around a billabong, riparian vegetation or the verdency of an oasis, the mix is complex and regenerative but the driver is a reliable local water supply.
  • under my system of mounds it is clear that the worm exudate activity extends down hill from the pots t rims like a layer of slowly spreading dark chocolate syrup. Worms treat the pot walls like an underground tenement house because the habitat is cool and moist. Clay pots = happy worms.
  • I brew up a 'tea' mix based on aloe vera juice + kitchen washes/soaks which I water over the garden mounds and valleys.In my mind, I see myself, in the first instance, as caterer to the worm kingdom.Contrary to what may be written elsewhere, do not irrigate you pots with colloidal waters(like grey water) or add liquid fertilisers -- as these mixes will only gum up the pores in the clay. 
  • clay pots perform more efficiently as the surrounding soil shifts from sand to loam. In this conversion your best ally is not only vegetative matter like mulches but your "ever so 'umble servant", the earthworm. 
Comment by Dianne Caswell on August 1, 2016 at 6:39

You are always coming up with Great Ideas that not only help you out but others as well. That's what BLF is all about. Thanks for sharing Dave.

Comment by Elaine de Saxe on August 1, 2016 at 5:50

Neat idea. I bought 4 wine coolers and their fiddly lids … shadecloth to the rescue.

Comment by Dave Riley on August 1, 2016 at 0:55

When cutting the cloth, allow some skirt so that there is enough overlap that, aside from allowing attachment, also functions to shade and insulate  the sides of the pot that sit above the soil.Even mound soil and mulch up against the shade cloth where it drops on the outside of the fold.

Filling the pots is like filling a kettle. The sound of the water tells you when the water level approaches the rim. When the pot is full, either water pools on the surface of the shade cloth or waves undulate its mesh -- like a heat retention mat on a swimming pool.

The cloth also prevents any splash back  ...and since the cover is a thin membrane, I suspect these 'lids' will not retain the heat like the stoneware plates did.

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