We know that colder temperatures are coming – and soon. According to NOAA, Steamboat’s average date of a temperature below 32.6 deg F is August 20th and below 28.6 deg F is September 7th…guess we blew right by those dates this fall! It’s time to give up, go inside or get out the Season Extension armaments.
When we talk about Season Extension, we are referring to a variety of human-applied garden accessories that help us gain a couple weeks on either side of the short mountain growing season. Basically, you are either keeping heat in, blocking radiation from a cold clear night sky, and/or adding heat to provide frost protection. Once it gets in the mid-twenties, you might as well throw in your trowel, unless you’re prepared to spend more money on heating than the worth of your vegetables. You may have heard or read about these Season Extenders: Row Covers, Tunnels, Cold Frames, Hoop Houses.
Floating row covers are a synthetic fabric that you place over your plants. It comes in increasingly heavy weights, from insect and mild frost protection to 5 or more degrees of protection. The heavier the cloth, the less sunlight gets to your plants.
Plastic-covered low Tunnels can increase the growing season by a month at either end (although wind and snow might cause damage if used too early or too late in the growing season). These tunnels are made by bending hoops from ½” PVC pipe, electrical conduit, or 6- or 9-gauge wire, and putting sturdy plastic over the hoops. UV-stabilized greenhouse film will last more seasons than untreated plastic, but it costs more. The plastic needs to be pulled tight to form a tunnel, weighed down along the sides with sand bags or large rocks, and staked out at either end. This strategy can be attached to a raised bed (my personal favorite) to make a Hoop House.
Cold frames are usually a frame of glass or plastic placed on a raised bed. These are potentially a little more work but a great way to repurpose building materials, old windows or window frames.
Remember – anything covered in plastic will need to be ventilated on sunny days or temperatures inside the enclosure may rise enough to kill those plants!
Jackie Buratovich was raised in a central California farm family and loves making things grow in and around a solar home here in Routt County. She received her Master Gardener training in Boulder County in 2003, and acknowledges that while growing conditions here are more challenging, being back in an agricultural community is like coming home and being able to grow greens outside all summer long is a bonus!