I caught up with author and horticulturalist Robert Kourik to dive into the details about why drip irrigation saves water and makes vegetable gardens more productive.
Q: Why is drip irrigation a better choice than overhead sprinklers or even hand watering?
You first have to understand that in any garden, the goal is building healthy soil. Healthy soil contains enormous amounts of beneficial critters: worms, bugs, bacteria, algae, etc., each with its own small but vital role in making soil fertile and workable. Most of these helpful little organisms need oxygen; they also need to be able to exhaust slightly toxic gases—sort of like minuscule farts—resulting from their metabolic activity. To allow this normal venting of gases, the soil needs healthy pore spaces.
Sprinklers, while relatively easy to use, are likely to flood the pore spaces of the soil, by completely saturating its upper layers. This over-saturation, if continuous, or if repeated regularly, will kill some of the soil life.
This is where drip irrigation comes into play: With drip, very little of the pore space around an emitter is flooded; soil beyond the small anaerobic wet spot is moist, but pore spaces, due to capillary movement of moisture, are not saturated, and the soil life remains active and viable. This may explain why plant yields can increase while water is being conserved with the use of drip.
Q: That’s wild—less water actually leads to higher productivity. How much water can someone save?
All of the agricultural studies suggest water use goes down 30–50% with the installation of a drip system. My favorite study was is about growing chilies in Sri Lanka. In a 2002 study, researches saw a decrease in water by 34–50%, while production rose 33–38%.
I have an eBook, Greater Garden Yields with Drip Irrigation, that is filled with studies about drip irrigation decreasing water and increasing yields.
Q: Drip irrigation is a win/win for water use and plant life! How do we learn more?
Buy the 2nd edition of Drip Irrigation for Every Landscape and All Climates. It's available in print or as a downloadable eBook.