Water conservation

I live in a desert, with the average rainfall being right around 12 inches (about 30 centimeters) per year. That's ALL year, not just during the summer. I have to laugh when people talk about a drought, then say they ONLY get 10 inches of rain per month. The last time we got rain was about the beginning of May.

Under those circumstances, water use is extremely important. I try not to use anything from outside--no herbicides, pesticides, or fertilizers, I harvest my own seeds...and then I have to cancel out all my gains by buying water from the city. During the summer, I use about 60,000 gallons of water per month. A great deal of that is used to water lawns (a long story that I won't go into at the moment--sufficient to say that the lawns will stay for a while longer).

So let's round (just to make the calculations easy) and say I have a quarter of an acre. That's 10,890 square feet, or 1.5 million inches. If each inch receives just 10 inches of rain, that's more than 15 million inches or 68,000 gallons falling on my property. If I were able to use all of that (and assuming that I'm no longer feeding thirsty grass that needs to be watered three times per week) I could last much of the summer without supplemental watering.

Several problems with that scenario. First, water runs off. Second, water runs down (through the soil and into the water table) and third, water runs up (through evaporation).

The first is relatively simple--slope and grade the soil so that the water has to stay. A dip in the soil of an inch will prevent a great deal of water from running downhill. Fill that dip with mulch, you have a handy catchment area that will slowly drain that water into the soil over time.

The second, there's nothing I can do other than strip off the top 30 feet of soil (well honestly it's sand and rock, not soil), put down pond liner, and put the soil back. Uh...no.

The third, again, is relatively simple. Mulch. Lots and lots of mulch. Mulch every year. Seriously, if I wasn't buying 60,000 gallons of water per month how much mulch could I buy? LOTS.

On my property there is one area that is consistently hotter than anywhere else. I have never been able to do anything with it--everything I put there died. Repeatedly. But this year I did something different. I mulched it. As deep as I could, and this summer every bit of extra plant material I could scrape up went up there. Right now it's requiring one deep watering per week, as opposed to last year when I was watering it every single day and STILL everything died.

Now I'm seeing mushrooms in the mulch, and weeds I've never seen before. The plants are thriving--except in the areas where I haven't finished mulching deeply. There, they struggle, but they're still alive and kicking.

So if I could mulch the garden area like that, could I get away with once a week watering? I already water only twice a week in the main garden, and it has much better soil than the hill area. I'm guessing every other week, or even less once the system is established. That right there would cut my water usage a great deal.

This year I tried something new. Well, several somethings, but this year I didn't till the garden. I planted, and waited. And the plants thrived, with no additional water at all. I didn't water the main garden until the end of May, and everything grew just fine. So if I mulched it deeply, would I be able to stretch that to the end of June? The middle of July? The whole summer?

I don't know, but it's worth a try.

Permaculture (in a sense)

Over the winter I started doing research into permaculture, learning that we've been using permaculture principles for some time without knowing it. :) Very little organic matter leaves this yard--it's all recycled, one way or another. Leaves and grass are compost, food debris goes in the compost pit. Thicker wood that can't be composted is burned for ash or used for any number of other things. The land is sloped so that there is very little runoff, and xeric plantings deliberately placed where the sprinklers don't reach.

Water is our Achilles heel, but permaculture has a cure for that.

We live in a desert. It rains in the spring and fall, a bare handful of times per year. Snow during the winter mostly runs off rather than soaking in. In all we get about fifteen inches of water per year. Summer temperatures run easily into the 90's and 100's, with near 0 humidity.

This year water prices are going to double or triple, and with more than a quarter acre of lawn and garden that's going to hurt. With that in mind, a few years ago I invested in a water catchment system to catch water off the roof. It's nearly complete. I also finished one of the drainage systems, carrying water from the downspout on one corner of the house across the grass and into the raspberries.

Two years ago we put in the drip system, and the secondary garden is watered by the lawn sprinklers. I'd much rather water vegetables than grass.

So this spring I ran a test. All of the vegetables were put in the ground--and left alone. The only water they've gotten was the rain two weeks ago. With temperatures in the 70's and 80's, I would have expected the water to evaporate quickly, leaving the seedlings languishing. If that had happened I would have watered, but they all appear fat and happy. As of last night (before the rain) the soil in the main garden was dry only two inches down, and in the western garden one inch. Seedlings are all up and amazing. Two transplants have been lost--one tomato, broken when a wall-o-water fell over on it, and a licorice seedling that something ate. Neither died from lack of water.

Last spring we were watering constantly, and the water just seemed to drain away, leaving the soil dry again within a day or two.

Something has changed.

I think we're working with a combination of things. First, each year early in the spring we till up the garden, which allows air in, fluffs the soil so to speak, but also creates more space for water to evaporate from. All that water that's settled deep in the soil during the winter evaporates off. We then plant into this aerated soil, and keep it watered until the seedlings come up. Because of the tilling the soil is broken up deep, allowing all the water to drain off. This year we didn't till, so the water that was in the soil is staying there.

Second, I mulched the surface as much as possible. Grass went down all last summer, and leaves in the fall. This year we will again mulch deeply with grass and leaves, as well as continuing with the deep compost pit.

By planting so that all soil is covered by something living (or a good thick layer of mulch, or both) we should minimize evaporation from the soil. With the use of consciously recognized permaculture principles (rather than just doing what feels right), I'm hoping that water use will be minimized this year.

The recipe for a water-wise garden:

Soil with plenty of organic matter
Mulch (next year's soil)
Plant densely
Catch and reuse (catchment tanks)
Water wisely (drip lines)