High Altitude Gardening: Beneﬁts of raised-bed gardening
April 22, 2012
It’s early spring and some of us are itching for a reason to spend an afternoon out in the beautiful spring sunshine. Don’t have a garden? Or think it’s too early to get into the garden? Actually, as soon as the snow melts, I’m out preparing my vegetable garden for planting.
Many of you may think the idea of a vegetable garden at high altitude or starting one in the cold, spring snow is not practical, but not true. In fact there are many vegetables that don’t mind a little snow and frost, and even thrive in the cooler temperatures of spring.
High-altitude gardening presents many challenges to the would-be gardener, but learning the right types of vegetables and some cold management techniques can bring a prolific vegetable harvest to almost anyone, at any elevation, with some considerations and limitations.
One technique is called raised-bed gardening. By constructing a boxed area within boards of wood or timbers or rocks, and elevating the growing bed above the surrounding ground, 4 to 8 inches or more, the high-altitude garden will see many benefits.
First, the raised garden warms much faster in the spring, and maintains a higher temperature than the ambient ground temperature. The average temperature of most mountain gardens in summer can be around 40 to 60 degrees. But most vegetables like it a little warmer, around 65 to 75 degrees.
With a raised bed, it is very simple to prewarm the growing bed in the early spring by covering the bed with clear, heavy plastic and securing it to the box with staples or weights, creating a mini-greenhouse. Heat trapped under the plastic on warm, spring days can quickly thaw and heat up the dirt and be ready to plant by April 1, even when it is still snowing into May.
But you can only plant the cold-tolerant vegetables at this time, like spinach, kale and bok choy. Once planted, you can let late spring snows cover the new seeds. As soon as the snow melts again, the seeds will sprout and grow with the warming days. Or you can further help your new seeds by constructing simple hoop houses or cold frames within your raised beds, to keep the snow off. Be careful to vent the covers each day, so you don’t cook your new seedlings. Managing your garden’s temperature is much easier with a raised bed and is an important aspect of high-altitude gardening.
To construct raised beds, build the boxes in increments of 4 feet. A box 4 feet by 8 feet works well so you can walk around it, and easily reach across it. Simple carpentry skills are needed here, along with a drill and a saw. Just use 2-by-6-inch or 2-by-10-inch boards from the lumber yard. Or you can order a kit online if you Google “raised bed kits.” Kits can be expensive, but require only a screwdriver to assemble. Once assembled and set in a sunny location, load in the topsoil and compost and plant your seeds. By having the growing bed in a box, you never walk in the growing area, so you don’t compact the soil. Raised beds are also much easier to weed and to water and fertilize because of the smaller areas that are planted.
Lori Russell is a local gardener, professional landscaper and teacher of high-altitude techniques. She lives and gardens in Eagle.