Some say drip irrigation is the best. I half agree. I’d modify it to say that drip, including its cousin the micro-sprinkler, is better than other methods of irrigation for many situations, but that it does come with its own set of downsides and challenges.
Yet I use it in most of my own yard, have for many years, on vegetables and fruit trees and, at least for me, its positives outweigh its negatives. The main reason I see drip irrigation in such a positive light is that I’ve learned to work around its weaknesses. That’s what I’m hoping to help you do in this troubleshooting guide.
I teach workshops on using drip irrigation from time to time — in fact, I’ll be doing one tomorrow down at the Tijuana River Valley Community Garden — and I use this guide as a handout. In it, I try to be both brief and clear, but I recognize that many terms may not be familiar, so in this digital version I’ve linked to some images and descriptions (in blue). Here we go . . .
–Warmth makes materials easier to work with so lay materials in sun, or
–Fill mug with hot water; dip tube end into, or
–Heat tube with match or lighter
—Filters are first line of defense
—Micro-sprinklers: run at high pressure briefly to blast out debris; poke with toothpick; use large orifice models, as they clog less often
–Last emitter on line often clogs first; cut off and connect new segment with emitter
–Flush lines periodically by opening end, especially after repairing or adding new emitters/lines
–Set automatic timer to run system while you are normally around to observe (not the middle of the night)
–Larger “half inch” tubing (thick as a carrot) clogs less often than smaller “quarter inch” tubing (as thick as a pencil)
Watering Plants with Different Needs
–Using emitters or micro-sprinklers with different water volume outputs allows plants with different water needs to be watered on same schedule (i.e. same valve/station), or
–Use multiple emitters or micro-sprinklers on bigger/thirstier plants
–New vegetable or tree added? Handwater to supplement if necessary; vegetable will grow roots into surrounding soil after one or two weeks; tree will take one or two months; be sure emitter is directly over rootball at first (yet best to not touch stem)
–Be not beholden to your drip system: For example, overhead water for carrot seed germination; occasionally spray potato foliage with hose to clean and prevent mites
–Adding inline shut-off valves gives increased flexibility; can add one to a line that serves one plant only or a line that serves multiple plants, and then adjust to control water flow
Run Times and Frequencies
–Most common error is not running system long enough at any one time
–Variables that affect how long and often to run system include: emitter output (higher output = less time needed); number of emitters per plant (more emitters = less time needed); soil type (sandier soil = less time needed, but needed more often because of less water-holding capacity); season (summer = more often, and winter = less often, but note that run time need not change); plants (avocados need more water than grapes); weather (heat wave makes plants thirstier); climate (plants inland need more water than plants near beach)
–Because of numerous variables, always observe and adjust; dig to discover truth of soil moisture where the roots are
–Don’t water again if soil still wet; don’t water so much that penetrates far below roots
–But for reference: Drip on vegetables for me have done well running system for approximately 45 minutes each time; in summer, at highest frequency, about every three days, but every two weeks in winter; my drip lines are 0.5 gallon per hour emitters spaced nine inches apart; soil is sandy loam; location is Ramona, twenty miles from ocean
–And for reference: Micro-sprinklers on fruit trees for me have done well running system for approximately four to five hours each time, which applies two to three inches of water under canopy; in summer, at highest frequency, it’s about every six days for avocados, ten days for citrus, two weeks for deciduous fruit trees
–Note that trees less than one year in ground need water more often than above
–Use tuna cans to estimate sprinkler output in inches; use a bucket (place sprinkler inside) to measure output in gallons
–Changing where water is applied is easiest on plants if done in late winter through early spring; plants may die if done in summer or early fall
–Slopes and uneven output: use pressure-compensating emitters, or; plant thirstier plants lower; water as infrequently but deeply as possible; install backflow prevention valve
–Slopes and runoff: first moisten soil surface with 1-3 minute pre-irrigation; slightly bury dripline; locate emitters and sprinklers uphill from plants; add coarse wood-chip mulch
–Sandy soil and raised beds: emitters must be spaced no farther than 12 inches to avoid “chimneys”
–Can test lateral spread of water in your soil by filling milkjug with water, poking hole near bottom, then after a day, digging to discover
–Fittings come apart: pressure might be too high; install regulator or manually keep low at faucet
–Tripping hazard: bury tube; stake to prevent snaking and rising; insert wooden stake beside sprinkler
There’s a lot more to drip irrigation, of course, but those are the most commonly challenging topics as far as my experience goes.
Would you like a copy? Click on this link for a pdf download of the handout version: “Drip Irrigation Troubleshooting Guide.” This version is two pages long and doesn’t include the introduction or any photos. It’s just the meat. But feel free to keep it on your computer or phone, print it and post it in your shed, photocopy it and give it to a gardener friend.
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