Growing More Food with Less Water
For many of us on Galiano, limited water supplies present a challenge for growing food. This is due in part to our Mediterranean climate of wet winters and dry summers, and in part to our rugged topography, which infiltrates only about 20% of winter rainfall. While the climate crisis will intensify our annual drought, Galiano has always been on the dry side: according to the 2017 Southern Gulf Islands Food and Agriculture Strategy,
“Early settlers [on Galiano] found the soil unfriendly and water scarce and turned their attention to fishing, hunting, sheep and fruit growing to make ends meet. Galiano was generally regarded as the least arable of all of the Southern Gulf Islands.”
Our budding Food Forest at the Millard Learning Centre is no different – water is scarce, and the soils are poor. Below are some time-tested strategies we’re using to grow food with less water.
Hügelkultur: putting wood to work
We may not have much ‘friendly soil’ on Galiano, but we do have lots of wood! Hügelkultur is German for ‘mound culture’, and refers to the practice of building large raised garden beds on a mixture of coarse woody debris, organic detritus, and compost. The woody debris breaks down slowly over time under the mound, contributing micronutrients, encouraging beneficial fungi and soil microbes, and – importantly – acting as a woody sponge to retain water during drought. The GCA Food Forest is designed around five large Hügelkultur beds, which play an important role in helping our fruiting trees and shrubs endure dry summers. One year, we discovered that our automatic drip irrigation system had been turned off accidentally for most of July, but none of our perennial plants showed any signs of stress!
Ollas: clay pot irrigation
We live in the “Pacific Northwest,” but we may have more in common with the “Desert Southwest.” There, farmers have been employing clay pot irrigation for generations. The idea is simple: unglazed clay pots are partially buried, and then plants are established around them. These clay pots – or ‘ollas’ – can be periodically filled with water, which then slowly seeps out through the porous clay body to water the plants as needed. Clay pot irrigation saves time and labour, has been shown to be much more efficient than commercial drip irrigation, and can be achieved using handmade ceramics or standard terra cotta garden pots. This year, we’re establishing an olla demonstration garden at the GCA Food Forest, using custom ollas from IF Ceramics.
Rainwater Catchment: where there’s a roof, there’s a way
On your next visit to the GCA Food Forest, you might notice what looks like a concrete yurt! Don’t worry – this isn’t our new intern accommodations: it’s actually a ferrocement rainwater cistern. “Ferrocement” refers to thin-walled concrete on a rebar and wire frame, and it is used widely in the majority world, where labour tends to be less costly than materials. This cistern can hold over 45,000 liters of rainwater! While ferrocement is labor intensive to build (it took 30+ volunteers and GCA staff over 400 hours to complete this cistern!), it has several advantages over HDPE plastic cisterns: it can be built in situ in remote areas without roads, it is cheaper in terms of material costs, and it has been shown to use 40% less embodied energy and less than half the carbon emissions of a similarly sized HDPE cistern.
Regardless of the size or what materials you use, harvesting and storing rainwater is a key strategy to reduce our reliance on groundwater for growing food.
Want to learn more? Come visit the Millard Learning Centre, and check out the GCA library – we have a great selection of books on applied water conservation.