Now that my present garden is working its way into its adolescence I have the option to fiddle with its makeup and constituent parts.
After designing the thing -- albeit by trial and error -- and layering all the matter and stuff to make the plants grow I've been fretting over the conundrum of how to irrigate it.
What a headache irrigation is! How essential, how basic, how very Australian it is to wonder how to keep the water up to plants...
And there is no clear consensus.
Since we've had a very wet Summer, I've relied on hand watering . But when you live on sand -- I mean real sand of the golden seaside variety -- it's no good watering deep because there aint nothing down there but more sand.
While I've built up the mulch layer aggressively and perched my garden atop the sand, I face the complication that mulch can be often impermeable and also steal the water from anything below.
Despite all the drip feed irrigation systems, I've installed Leeaky Hose
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.
Cheap. Easy. I can lay one hose per length of bed --even on sand-- by running it below the mulch layer.
It's like putting a water snake to bed and tucking it in.
And since Leeaky hose functions best at low pressures I run water into the hose from an upright, raised 100 litre water barrel (pictured above left). Over the space of several hours (over 6 hours I find is appropriate) I can control how much water I use to irrigate any one 5 metre long bed. In my setup I can irrigate one or two beds at the same time by relying on gravity to sweat the water into the soil after I've filled up the barrel from the house rain water tank.
I move the barrel around the garden rather than rely on long feeder lines.
Using such a precise -- and seemingly small ( a standard domestic 3 minute bathroom shower sprays about 60 litres of water) -- allotment such as 100 litres enables me to precisely focus on my water budget. While I have a 3,000 litre rain water tank, that volume should not be enough for the garden for the whole year despite my considered savings. (But then it may...?)
So while I'm wondering when I will run out of harvested rain water -- with a eye on my location's median rainfall per month -- I suspect that I'm making the best use of the water the heavens give me.
Irrigating under cut grass
Since my primary garden resource is grass clippings (and manure and seaweed...) I've learnt that you have to now and then 'fluff up' the grass clippings mulch so that the clippings don't mesh together and prevent air and water getting to what lies beneath. Meshing can be an advantage sometimes -- like a wooly blanket -- but grabbing handfuls of dried cut grass and sifting them is a great way to sense the happenings at the soil level -- and for now, I don't as yet have that much humus type soil.
So far, using Leeaky, I can monitor how effectively the dampness is spreading across the top layer of what is slowly becoming excellent sandy loam. Previously by relying on hand watering the irrigation was uneven and often simply wasteful as the rush of water simply drained away into the sand and all that I soaked was the mulch.
Of course I can do other things too. I can locate and bring home some clay to spread about. I can harvest more rain water off my 158 square metre roof.
So that now, after months of mulching I have a garden which is two thirds grass clippings mulch and one third gravel mulch..and a wee lawn. Where vegetables grow (one third of the total area) there's also manures, seaweed, compost and whatever I can find to build up soil quality and depth.
After reviewing the cost of further rain harvesting ventures, it seems that the cheapest and most efficient way I can harvest more rain water is to put in a pond -- on sand!(by using a liner)
That, of course, leads me into my passion for pondlife and the fact that I've always created several ponds anywhere I've lived and grown stuff.
I have one small pond already; another small one is scheduled to follow soon...then the big one -- the lake! -- perhaps.