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.