In an intriguing comment to my blog on the world's best tomatoes, Linda from Northern California asked about "dry farmed" tomatoes, which are grown with little or no supplemental water. Linda says the dry farmed tomatoes grown by a neighbour have a remarkably intense, delicious flavour, and I’m not surprised. A little drought stress deepens the flavors of ripening tomatoes, melons, and several other garden crops. In fact, one of the reason commercially-grown specimens often taste flabby is because they are pumped up with water.
Enter dryland gardening, in which every drop of water is regarded as precious. If you live in a climate where rain is often scarce when your garden needs it most, you’re a prime candidate for dryland gardening. Thick mulches are mandatory to reduce surface evaporation, and it’s always a good idea to position a soaker hose before you pile on the mulch. Made from recycled tires, soaker hoses weep out water when the faucet is turned on at very low pressure.
Beyond mulches and soaker hoses, gardeners in different parts of the world have discovered more ways to keep plants watered in the dry season:
Berms and Basins
In the American Southwest and West Africa, many gardeners surround plants with low earthen berms, forming basins that catch water. Zuni tribes use this technique in creating waffle gardens, which capture and retain water better than regular rows. Berms about 4 inches (10cm) high made of loose soil also provide a little shelter from sun and wind, which is especially important for young seedlings.
Shade screens that cool down plants’ root zones work miracles in hot, dry climates. Snow fencing placed along the south or west side of a tomato row works great, or you can make shade screens by attaching pieces of cloth to stakes. Or maybe you can use plants. In Techniques for Dryland Gardening, David Cleveland and Daniela Solari report on the Egyptian practice of protecting seedlings from scorching sun with low, wattle-type fences made from corn or wheat stalks.
In Africa, some gardeners have learned to bury organic materials in holes or fertility trenches during the rainy season. As the materials rot, they form a reservoir of moisture and nutrients below the surface. In The Complete Compost Gardening Guide, Deb Martin and I describe a similar method called Honey Holes, which I often use when growing peppers and pole beans. I dig a hole, fill it with pulled weeds, grass clippings and other compostable stuff, and surround it with four peppers (as shown here) or a circular teepee of pole beans. In dry weather, water run into the Honey Hole slowly percolates an enriched brew into the root zones of the nearby veggies.
Keyhole gardens include the Honey Hole feature, only in the middle of a walk-in raised bed. Developed as a gardening technique for remote highland villages in Africa, keyhole gardens are catching on in other parts of the world thanks to this animation produced by the Send a Cow charitable organization. I haven’t built one yet, but I plan to!
Buried earthen pots have been used to irrigate crops in China for thousands of years, and they can be terrifically efficient. A regular unglazed terra cotta flower pot will do as a reservoir, though some people do buy and install special earthenware jars, called ollas, to keep their gardens watered.
Personally, I have no ollas, but an unlimited supply of plastic drink bottles awaits me at the recycling station. I use a sharp knife to jab 5 or 6 small holes in the bottom half of a bottle, and then "plant" it between tomatoes. After filling the buried bottles with water, I screw on the caps, which slows the percolation of water into nearby soil (see photo). Because all of the water in buried bottles is released several inches below the surface, not a drop is wasted. This is dryland gardening at its best.
- Barbara Pleasant