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.
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..."