Saturday, October 22, 2011

Gardening: Dryfarming

We used a lot of water at The Farm this year. In the excitement of the new garden, we weren't willing to take the slightest chance of any plant being thirsty. While the bills weren't bankruptcy, they certainly took the edge off any claim to have saved on food costs. (Then again, how much is a dead ripe red-to-the-middle strawberry worth? Mmmmm.)

So we'll be making some changes next year. The strawberries and at least some of the bush beans will still get all the water they want, but the tomatoes and peppers and squash and sunflowers and any number of other things will have to do a certain amount of doing without. I'll grow the cucumbers that didn't get bitter this year during hot spells, in the hope that they'll be equally amiable about low water. The corn will have more lavish soil but less water. The herbs and perennial flowers will get a chance to show how nicely established they are. And we're thinking about experimenting with dryfarming. (Drygardening?)

What's dryfarming, you may ask? It's growing without irrigation, using the water that's naturally stored in the soil. Luckily, I'm gardening in Oregon, where the soil is saturated every winter, so there's a moisture bank to draw on. But all the same, dryfarming involves a lot of changes.

The most obvious change, as far as I can tell, is plant spacing - it's drastically expanded for dryfarming. Corn is normally spaced somewhere between six and eighteen inches apart, depending on the variety and situation. Steve Solomon's _Gardening Without Irrigation_ recommends a dryfarming spacing for corn of three feet, and that's for a climate that might be a bit cooler than mine. He also mentions Arizona gardeners that have grown un-irrigated corn at at ten foot spacing. One cornstalk in a space the size of a small bathroom. Yikes.

Steve Solomon has (or had) sixteen acres; space isn't a big issue for him. We have a fraction of an acre, but all the same, I'm planning a little experimenting. A couple of dryfarmed tomatoes at a five or six foot spacing. A few corn plants at a three-foot spacing, or maybe I'll go with two feet and water them a bit. A few un- or lightly- irrigated pole beans. I'll dryfarm at least one patch of garlic -- some sources say that since garlic gets a good deal of its growth in the wet spring, this should be easy. Some sources fervantly disagree. We'll see.

Of course, all that wide spacing does you no good if you allow weeds between the plants to suck up all the water. So dryfarming will require essentially perfect weed control. And, to my surprise and dismay, apparently a nice weed-suppressing mulch actually increases water loss in a dryfarm situation. The explanation for this oddity is that mulch keeps the top layer of soil damp, allowing water to travel by capillary action from the deeper moisture reserves all the way to the top of the soil, where it evaporates away. Without mulch, the top of the soil turns bone dry and and doesn't allow that surface evaporation. If you break it up to further destroy capillary action, you've created a "dust mulch", a phrase that still fascinates me.

So. Dryfarming. I'll let you know how it goes.

Image: By Li-Sung. Wikimedia Commons


  1. CF,
    Have you considered augmenting with rainwater? We have an 800gal rainwater system that saved our bacon (okay, our lettuce and tomatoes) during the incredible drought we had in midsummer. I'll send you some photos. El O made the system out of discarded plastic barrels (you can usually get them from municipalities for either free or less than $2/per. Built a stand for gravity-feed, hooked the system up to one of our downspouts and vi-ola, baby! Agua. H2O. HappyDance. The entire setup cost less than $30.

    Maybe a backup option for you? We live in rural IL, where water is hyper-expensive. Can't pay to water the garden.

  2. Hey, Musette! We normally have at least six weeks of no rain in the dry season - at least, that's what I've read; if I'd been asked I'd have said that it's more like ten to twelve weeks. So I couldn't irrigate at a normal rate with such a system, but we might be able to store some winter rain for the summer. Hmmmm.

  3. we have pretty much the same thing, come late June-July, which is when I store the rainwater for. Depending upon how much you are growing (and what) that 800 gals will take you through about 2 months (we're assuming you've had pretty decent early rain and have the beds set up for traditional water retention). I use the direct hose-to-the-ground method at the crack of dawn and the plants are good to go for 2 days. 12 tomato, 6 pepper, 4 rows of corn - all made it through with that. Email me at gmail (addy evilauntieanita) and I will send you some photos of the system. It's also a great backup, in case you have to barricade yourself within your property (in case of a zombie attack, don'tchaknow :-)

  4. Cool! It's always important to be prepared for zombie attacks. Of course, in Ashland I'm thinking that they'd be vegetarian zombies, so a thriving vegetable garden might actually attract them. Hmmm.

    I'll email. :)