About the SFMGA

Monday, September 17, 2007

Drip Irrigation

During the hot summer months, we use over half our water outside, mostly to water lawns. We need to learn ways to give plants the water they need to grow and thrive - no more, no less - and to do it as efficiently as possible.

Of course, rain is this best irrigation system, when we get enough. Look for ways to harvest the rainwater that flows from your roof through canalés, gutter downspouts, and other places. You can find plastic barrels to gather water from these runoffs, then later run a hose from the barrel spigot to irrigate your plants.

You can redirect water flow in your yard by creating berms (hills) and swales (depressions). Maybe you'll also notice ways to adjust your concrete and stone paths to redirect water to your plants.

If you'll make sure the mulch around your plants is at least 3 to 4 inches thick, you'll boost water retention in the soil, reduce soil temperature, and even suppress weeds. That's 1 cubic yard of shredded bark or crushed rock to cover 100 square feet of lawn.

Consider drought-tolerant shade trees: they act almost like mulch, cooling the soil, and thus slowing evaporation. Santa Fe, at some 7000 feet of elevation, has very intense sun exposure. Most plants appreciate any shade they can get.

Short of rain, drip irrigation is a great choice. A drip system delivers water slowly and directly to the plants' roots. This cuts evaporation and runoff, and avoids the overspray that's often common to other methods.

If you install a drip system (or have a pro do it for you), make sure it drains properly to prevent freezing. You may be able to convert your current irrigation to a drip system with multiple outlet adapters for the drip emitters. Of course, as with any irrigation system, you (or your pro) will have to check and adjust your drip system every now and then.

Many folks use graywater for irrigation. (Graywater includes wastewater from showers, baths, and clothes washers, but NOT from a toilet or kitchen sink.) Some folks use a hose to conduct clothes washer water directly to the yard, or buckets to collect shower water while they're waiting for the hot water to arrive from the other end of the house.

If you'll follow these precautions, our state and local governments won't bug you about using graywater:

  • Never use graywater for direct consumption.
  • Chlorine bleach may damage plants, especially if it touches the foliage: avoid using graywater from the wash cycle if bleach has been used.
  • Don't let graywater run off your property.
  • Use only water from clothes washing, bathing, or a bathroom sink. Don't use water that has come in contact with soiled diapers, meat or poultry, or anyone with an infectious disease.

Drip system maintenance checklist

Any irrigation system needs regular inspections, adjustments, and repairs to run best. Every month, check for leaks and clogs. Clean the clogs, and repair the leaks. Beyond that:

Spring
  • Adjust the controller for watering times and durations.
  • Replace the controller's backup battery.
  • Replace filters.
  • Make sure the drip emitters are getting water to the entire root zone of each plant.
Summer:
  • Adjust the controller for watering times and durations.
  • Make sure the drip emitters are getting water to the entire root zone of each plant.
Winter:
  • Turn off the system: it's not much needed now, and turning it off will help prevent freezing damage.
  • Drain the system, and leave the filter housings open.
  • When the system is needed, open the valves manually.
  • On occasional warm days, you can restart the system as long as you follow the first two Winter steps after you're through watering.