 From Joel Prudhomme, UUCGV Green Team Member It is becoming more apparent to us in western Colorado that climate change’s increasing drought is going to impact the availability and cost of water for our lawns, shrubs, trees and gardens. We must realize that lawns are the least necessary and very water-hungry of our vegetation types.
Our sunny desert climate dictates that irrigation methods that spray water over large areas (like for lawns) during daytimes are hugely wasteful----not to mention encouraging weed growth everywhere. Impact and pop-up spray systems for lawns should only be run during nighttime/cooler daytime periods--- to avoid evaporation loss. Spray-watering for long periods (e.g. one hour) for only 1 to 3 times per week puts water deeper into the soil for plant uptake later, minimizes surface evaporation and fosters deep plant roots. ”Furrow” irrigation (sending a stream of water down a small trench used for vegetables, orchards, and field crops) can often only require irrigating once every week or two. A general rule when to water: don’t water unless a flat-blade screwdriver can’t penetrate more than 2 inches into the soil. Better yet, take a small shovel and “peel back” a soil clump and then feel how much moisture is actually there! Drip and bubbler irrigation methods are much better options for non-lawn areas. Your household’s water source determines the materials you will need for drip/bubbler irrigating. If your water source is domestic, i.e. your ‘house” water supplied by a city or Ute Water, you will need a backflow preventer and pressure reducer for drip/bubbler systems. [Domestic “clean” water requires preventing water that has been in-contact with soils (that might have chemicals or pet fecal matter on them) from backing up into your home]. Domestic water is also often supplied at very high pressure (100 psi) that can cause pipe connections to come apart. Dirty “ditch” water comes from commercial irrigation companies. It is not sanitized (since it flows via mostly open, dirt canals) and often has various kinds of debris. Because drip/bubbler systems have very small emitter holes it is necessary to filter “ditch” water before entering drip/bubbler pipe lines. There are numerous kinds of filter assemblies with screens inside them to filter ditch water. Drip/bubbler systems need a filter screen of 120 microns (or smaller) to keep ditch water debris from clogging your small drip emitters or bubblers. [Domestic water can often get by without a separate filter assembly because the small screens in the pressure reducer catches any fine debris …and can be removed occasionally by hand to clean the tiny screen inside the reducer]. Drip/bubbler systems utilize black polyethylene (“poly”) or white/grey PVC (“plastic”) pipes and various kinds of connectors and emitters. Black “poly” pipe can be of several different types. One type is used for feeder lines (main or secondary,) another type is just for drip lines, another type is called “funny” pipe and used for small location adjustments for spraying sprinklers. Black poly pipe feeder lines use insert connecting pieces (with ring clamps) and threaded connectors. Black drip and funny pipe poly pipe use push type and/or threaded connectors. There are slight differences in different manufacturers’ drip pipe diameters. Don’t mix brands--- you’ll get angry trying to use connectors on the wrong brand of pipe! PVC “plastic” pipes are used only for the main and secondary “feeder” water lines and use PVC cement ( i.e. glue) and threaded connectors. Recently there has been more introduction of push connectors for PVC parts----- no glue needed! Then adaptor pieces will be needed to transition from PVC to the softer poly pipes for your drip/bubbler lines and emitters that are usually laid right on the soil surface. The emitters that actually dispense your water will be “flag” or “button” or “shrub” (bubbler) types. Some emitters also shoot a spray. However, those facilitate the evaporation loss mentioned---the very thing you are trying to avoid during a drought! Emitters are of fixed volume (i.e. 1 gallon or 2 gallons per hour); bubblers are often of adjustable volume by hand. Either type are usually punched and pushed into drip poly lines at your plant locations. Some factory drip lines have built-in fixed emitters every 12’ to 18” so no punching/pushing in is necessary. These also are self-cleaning and pressure compensating so there is consistent watering. These are well worth the small additional cost if you have lots of plants in an area or want to provide water throughout the very broad root zone of a shrub or tree. The other action that is crucial to addressing irrigating in our drought–increasing area is mulching. Mulching with shredded bark, leaves, grass clippings, non-flowered weeds, and even rock, keeps the direct sun from drying out the soil top quickly before plants can use the water. Mulching with organic materials, or rocks, and/or in conjunction with landscape cloth underneath keeps weeds from stealing water from your plants, also. The added benefit of organic materials breaking down and supplying the soil with nitrogen/other nutrients and increased earthworm activity aerating the soil is of immense value to all plants in your yard. Caveat: rock mulch has the adverse effect of reflecting more hot sunlight onto the plant ----thus stressing a plant during sunny drought periods. Substantial water price increases and mandatory restrictions from water suppliers are very likely in our near future. Replacing lawn turf and spray sprinklers and utilizing drip/bubbler irrigation systems now will prepare your yard and gardens for our warming desert climate. - Joel Prudhomme, UUCGV Green Team Member Comments are closed.
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