Even though the skiing may soon deteriorate, the prospect of an early spring is encouraging. In the greenhouse, seedlings await transplant while five-week-old chicks hunger for fresh pasture. But an early spring has its drawbacks. If we go through another growing season like last year’s, water resources will be in short supply. This year’s snowpack is currently below average, and early warmth will cause it to run off more quickly. If irrigation water runs short in Idaho, farmers could suffer losses like Midwestern farmers did last summer. It’s still too early to tell whether we’ll have a drought this summer, but in these parts, it’s prudent to expect the worst. Fortunately, there are steps we can all take this summer to better conserve our water resources.
If rain doesn’t fall and irrigation water doesn’t flow, we must preserve the moisture already present in the soil. The high clay content in our soil holds more water than rocky, sandy, or even silty soil, but turns to hard-pan with prolonged drought. To avoid hard-pan and hold even more moisture, organic matter (OM) is essential. Unlike the clay particles in our soil, OM acts like a sponge with exceptionally reactive surfaces. Crop residues, animal manure, and even hoed-down weeds are all types of OM that have this sponge-like character, once broken down. Just be sure to watch out for too much decomposition in the garden which may rob plants of essential nutrients and inhibit germination.
Our favorite way to increase OM is to add compost. Unlike raw plant materials, compost adds readily available nutrients, directly enhances soil structure, and feeds valuable soil organisms, especially earthworms. Earthworms integrate OM and develop channels for water to flow deep into the soil. If you have it, compost loaded with worms is the ultimate soil amendment.
Whenever soil is exposed to the air, it is vulnerable. At the same time, exposure allows the soil to “breathe.” In other words, soil must be covered enough to limit wind and water erosion, desiccation, and weed colonization, but not so covered that it inhibits gas exchange. To find a balance between too much exposed soil and too little, we will experiment with a variety of mulching methods this season. The first method is to lay down straw mulch in between raised beds and among perennials. This will protect the soil from heavy rains (and our feet) while holding moisture beneath it. The other method is to plant “living mulches.” These include plants like clover and vetch, which provide excellent ground cover and fix nitrogen. “Living mulches” are planted in between crops and left to winterkill after the crop has been harvested. The following spring, the remains of these mulches can be left as regular mulch or incorporated into the soil to build more OM.
As the “living mulch” concept suggests, one should allow plants to do most of the water conservation work. This summer, we hope to develop, divide, and propagate perennial plants to create diverse polycultures. Perennials generally develop more expansive root systems than annuals and often provide better soil cover. Many, like comfrey, clover, and lupine accumulate nutrients in the soil while adding large amounts of OM. Others leave behind channels (much like worms do) that funnel water deep into the soil. Through experiments with new species and varieties of edible, ornamental, and biologically beneficial perennials, we hope to create areas that are self-sustaining with very little rainfall.
Some perennials are ecologically beneficial and provide food. Fruits like apples, raspberries, and strawberries get plenty of attention, but currants, serviceberries, gooseberries, and thimbleberries are delicious and more drought-resistant. With a little bit of practice, an enterprising gardener can divide and graft these bushes to develop a lively berry patch. There is also a wide range of perennial vegetables that do not get all the hype they deserve. Nettle, sunchoke, rhubarb, lovage, horseradish and many others are well-suited for this climate and add unique character to home cooking.
Of all the perennials already living on the farm, the most important group is the grasses. Grass maintains balanced soil cover, provides habitat for beneficial insects and birds, serves as pasture for our chickens and pigs, and, you guessed it, increases soil OM. Along with the neighboring forests, the grasses on the property are the cornerstone of the farm ecosystem.
If last week’s warm weather is any indication, growers should be prepared for a hot summer. If you are a home gardener, start building organic matter in your garden by composting food scraps and any other plant materials you can get your hands on. While you’re at it, find a handful of earthworms to mix in. For the long term, try to establish an array of perennials and slow-growers like apple trees and fruit bushes. Once everything starts popping up, feel free to add some mulch (living or non-) to protect your soil. Your efforts will reduce water use and allow the garden to thrive, even if the rains don’t come.