Plants That Produce
Get Control Of
Your Irrigation
By Richard Frost
My neighbors are often astounded that my
water bill is drastically lower than theirs even though I have hundreds of
herbs and fruiting plants plus a teenage daughter(!).
The main ingredients of my frugal irrigation practices are: [1] appropriate
delivery of water, [2] significant layering of mulch on the ground and in pots
for plants that require moist soil, [3] easy to use
electronic irrigation controllers. Oh and yes, I have a single-turn shutoff
valve on my hot water supply for those teenage showers that are just too long.
Does your electronic controller require a
40-page operations manual? If so, replace it with one that has an
easy-to-understand display, requires no more than one button push or knob turn
to see the all the settings for any particular valve, and lets you choose named
days of the week to water. I am currently using the Rain Bird SST series
controllers which everyone in the family can operate.
For each valve connected to the
controller, make sure it is delivering water to plants with similar needs. A
good approach for shallow-rooted herbaceous plants is to wriggle some ¾ inch
soaker hose across the planting bed with both ends of the soaker hose attached
to the irrigation pipe to insure even distribution of water pressure (see
diagram). This also is an easy approach to replacing a water-hogging lawn: just
remove the grass, cap off all but the first and last sprinkler heads, attach
the soaker hose to the beginning and end, plant your plants near the soaker
hose, and cover with 3 to 4 inches of 1” diameter mulch. My favorite is
“Perennial Mulch” available for $1 a barrel at the El Corazon Composting
Facility in Oceanside (free to residents). Resist the temptation to use rock or
gravel in place of mulch: the rock will store heat and speed up soil water loss
through evaporation.
Deeper-rooted fruiting plants such as
tomatoes, eggplant, and fruit trees need a thorough soaking and then a rest
while water is absorbed by the plant and otherwise dissipates. Soaker hose
alone does not work well for this because it is hard to apply enough water in a
reasonable duration and the water is too focused; i.e., it goes down, not
across. I use ¼ circle and ½ circle “streamer” heads to apply water to the
mulch-covered basins of these plants (see photo). With this type of arrangement
you can easily supply the 15-gallon a week requirement of a maturing dwarf
fruit tree in a few minutes per week.
As long as you have electronic irrigation
valves in place, you might as well relieve yourself of the task of
hand-watering outdoor potted plants. First, make sure you have mulch on top of
the soil in your pots – ¼ inch orchid bark works great for this. Then run a
camouflaged length of ½ inch black plastic hose from an irrigation valve
alongside your pots. Insert lengths of 1/8th inch micro-tubing
between the hose and your pots and put a ½ circle “spitter” stake at the end of
each tube. You can purchase spitter stakes at irrigation stores for about $10
per 100. Position the stakes about 1 inch above the mulch so that the majority
of surface area is watered. With 70 lbs of water pressure, you can easily water
100 pots in 5 minutes.
SDHS member Richard
Frost is a certified edible gardening nut. For copies of past articles and more
information, please see www.PlantsThatProduce.com.
Reprinted with
permission from December 2009 "Let's Talk Plants," the newsletter of
the San Diego Horticultural Society, www.sdhortsoc.org
© 2009 San Diego
Horticultural Society
