Thursday 13 May 2010
Construction
1000 litre cubes are fairly common around here, for harvesting rainwater. So I built (actually there was a lot done by my neighbours Henriette and Michel and very good they were too) a concrete block work cube about 1.5m high and large enough to take the cube (1.2m by 1.4m). There was a decent foundation (there’s a tonne of water here). Then leave it to cure for a month or so.
Water distribution
Forget soaker hose, not enough pressure. So I landed up making collars (one per tree) of 12mm polypropylene garden hose, each being a ring with a single feeder point. The idea being that the size of the collar (about 1m) and the spacing between the 6 holes would about be capillary distance. Then tune the size of the holes in each collar such that they were even (about 1.5mm).
The thing that did surprise me was friction. It’s very evident at low pressure so, in order to give each collar about the same flow, all the tubes to the trees are going to be the same length. A nuisance but there we are.
The thing that did surprise me was friction. It’s very evident at low pressure so, in order to give each collar about the same flow, all the tubes to the trees are going to be the same length. A nuisance but there we are.
What might work?
I couldn’t find anything in one place on the net that addressed the requirement, hence in part, this diary. Research over various areas yielded the following points:
• Fruit trees like to be slightly parched and then drenched
• Water them first thing in the morning
• The only metric I could find on volume was for each one inch of thickness give 5 (American) gallons per week, so 20 litres per tree per week.
• I will have to provide my own water pressure.
• One bar is 10m head of pressure
• 1000 litre cubes are common here but that’s a tonne of water
• No way am I building a 10m tower, maybe 1.5m is possible
• 0.15 bar is very low pressure.
Low pressure is a real issue. Forget soaker hose, it needs 2 to 3 bar. Forget most automatic timers; they need pressure to close the valve. So what I landed up with was:
• A Gardena programmer, works on no pressure, batteries will run for the season. The user interface is clunky but it provides adequate facilities to open the valve at a time, for a period, every whatever.
• An associated Gardena soil moisture meter. Bury it close to one of the trees and it’ll tell the programmer if it’s wet or dry when the programmer is debating whether to open the valve. How cool is that?
• Fruit trees like to be slightly parched and then drenched
• Water them first thing in the morning
• The only metric I could find on volume was for each one inch of thickness give 5 (American) gallons per week, so 20 litres per tree per week.
• I will have to provide my own water pressure.
• One bar is 10m head of pressure
• 1000 litre cubes are common here but that’s a tonne of water
• No way am I building a 10m tower, maybe 1.5m is possible
• 0.15 bar is very low pressure.
Low pressure is a real issue. Forget soaker hose, it needs 2 to 3 bar. Forget most automatic timers; they need pressure to close the valve. So what I landed up with was:
• A Gardena programmer, works on no pressure, batteries will run for the season. The user interface is clunky but it provides adequate facilities to open the valve at a time, for a period, every whatever.
• An associated Gardena soil moisture meter. Bury it close to one of the trees and it’ll tell the programmer if it’s wet or dry when the programmer is debating whether to open the valve. How cool is that?
Subscribe to:
Posts (Atom)