Last weekend I saw the musical "Urinetown" at a local, small theater in Santa Monica. The musical was written roughly ten years ago and the basic premise is that we have been in a drought for 20 years and we need to conserve water. The way the government has decided to approach this is to ban private toilets so they can control water use. It is a metaphor of course, but it got me thinking about water waste and how so much attention is focused on saving water inside the house when the majority of water wasted is in our landscapes.
Why is that? Well we are very aware when we run the water in our bathroom sink or in the shower how much water is literally going down the drain. But in the age of automatic sprinklers we no longer go out to water with the hose as often or turn on our sprinklers manually. Now that the sprinklers automatically go on we are less aware of how often, how long and if it is really needed. We have become fairly detached from our gardens. Which is a shame I think.
I remember growing up in the San Fernando Valley and my dad going out and turning on the sprinkler valves with the metal key. This was not an every day event, but a few times per week and that seemed sufficient to keep our lawn looking good through the summer months. The rest of the garden was usually deep watered once a week with the hose running very slowly and moved down the bed every 20 minutes or so. My mother had roses, camellias and gardenias that were the envy of the neighborhood.
My point: if we get reacquainted with our gardens it will save water. Just like when we are in the shower we are well aware of how much water is going down the drain, if we are out with the hose more often and out when the sprinklers are running we will be more aware of how much water we are actually using.
In many of the classes that I teach I am asked how much water do plants actually need? It is hard to say definitively. It depends on weather, location, and your soil. That of course is on top of the kind of plant it is and its size. One rule of thumb is the deeper the roots the less water it probably needs. Plants with shallow root systems usually need more water. The best way to know if your plant needs more water is to look at it. How does it look? Does it look droopy? Is it starting to get brown leaves that are brittle? Unless your plant is in a shady area or has poor drainage it probably is not due to too much water. You can purchase a water meter that you can stick in the soil that will tell you.
To make things simple, I would say water no more than four times per week for 5-7 minutes. I tend to use the water more often but for shorter time periods method. This is for your traditional overhead spray heads. The overheads tend to overspray and there is so much evaporation that I think shorter periods are best and this allows the water to be absorbed into the ground. In Los Angeles we can water only two days per week. So I water once in the morning and then again late in the afternoon. This will allow the water to penetrate even more as the soil has already been watered.
There is a lot more to write and I will follow up with a piece on drips and underground systems. But in the meantime get outside and pay attention to the water use in your garden.