Vail high altitude gardening: Adjust your garden’s soil pH
Many gardening fanatics are already starting summer vegetable gardens in Eagle, Gypsum and Carbondale. The lower elevation in these places add an additional month or two to the growing season compared to places above 7,000 feet.
But it’s never too early to start cultivating healthy garden soil for spring planting. That can be done in the fall or in early spring, as soon as the soil can be worked and frozen ground has melted. To speed up the melting, you can spread dark compost over the snow. This will absorb more heat. Or cover the garden area with clear plastic visqueen to create a greenhouse effect. While you’re at it, cover the planting area with 2-3 inches of fully composted material and mix it in to the top 6 inches of garden dirt. Good organic compost can be purchased in bags at any garden center, or you can make your own.
The most important thing to a bountiful veggie garden is starting with good soil. But most of Colorado has very poor, alkaline soil. Often the best solution is to import good topsoil or buy some good bagged topsoil from the garden center. Consider getting a soil test from the Colorado State University Extension Lab (970-491-5061) for about $28. This will tell you the health of your soil and what the pH is.
The pH is a scale from 0-14 that measures the amount of acid or alkaline in the soil. Zero is most acidic, 14 is most alkaline and 7 is neutral, like pure water. Most vegetable plants prefer a slightly acidic soil of about 6.5 for best production. A soil test will tell you what you may need to add to improve the pH.
Truth is in Colorado, our soils are usually very alkaline, from about 7.5 to 8.5 and need to be supplemented to make them more acidic and more suitable for vegetables. Some garden centers will recommend adding sulfur to your soil (sold as a powder in bags) to make the soil more acidic, but the CSU help line does not recommend this. Sulfurs can mix with the high calcium carbonates in our soils, giving a net salt compound, which is not healthy for growing.
Even if you don’t do a soil test, you can’t go wrong by adding compost to your soil. Compost is the decayed, broken-down end product of all living matter. Compost results when organic matter such as grass clippings or leaves, is eaten and digested by bacteria. The metabolic waste of bacteria is a substance called humus. The humus will make the soil more acidic. Humus is the stuff in soil that gives the blackish cast and earthy smell. It’s what’s left over of the organic matter after it has been broken down by the billions of microorganisms, bacteria, microphages, fungi, earthworms and bugs responsible for decomposition. Humus is rich in minerals and nutrients vital to the health of all plants.
Composting is one of the best and easiest ways to recycle. Each year, 30 to 50 percent of all the waste at the landfill could be composted and help replenish the health of our soils and reduce landfill waste. All communities should be composting, and it should be part of every backyard garden.
Compost is easy to make even if you have little space. And it’s the easiest way to get rid of all your kitchen scraps and all yard waste like grass clippings and leaves. In a warm, sunny corner of your backyard heap a pile of yard waste and kitchen scraps, and eventually local bacteria will find it and eat it up. (If you don’t have this kind of space, a black plastic garbage can will do.) But in our cold climate in Colorado, this can take 6 months to a year or two for the bacteria to work their magic, as bacteria only grow in warm conditions. So there are a few things you can do to help the bacteria out and hasten their job, like layering, watering and covering the pile. ( I use only plant scraps — no meat or dairy — and have never had a problem with bears.)
But it can take more than a summer to make rich, black compost to feed your garden, so I always end up buying more at the garden center. Always look for organic compost on the label. A cheaper option is “Steer Manure Blend” mixed with an equal amount of peat moss. Peat moss is one of the best materials to help our soils, but the steer manure may not be organic unless stated on the label.
Lori Russell teaches organic high altitude gardening at Colorado Mountain College and builds gardens with All Seasons Service. You can reach her at 970-328-5324.