Regardless of the blustery weather and often below-zero temps, we are still able to grow crops during winter thanks to season-extension tools. Many types of produce are weather-sensitive and, if given the choice, would prefer to grow in frost-free weather. In Minnesota, however, that’s not always an option. Thankfully, there are all kinds of methods that you can use to help protect plants from the freeze and extend their growing season.
When stretched tightly over the garden’s surface, plastic tarp-like mulches help warm the soil, reduce weeds, and help the soil preserve moisture. Heat-loving crops like melons, peppers, and tomatoes like plastic mulches because the covering speeds up growth and development, allowing for an earlier harvest.
Ever heard of the greenhouse effect? That’s essentially what row covers do. These covers trap the sun’s warmth, which enhances plant growth and also insulates the plants at night through residual heat. Row covers come in all shapes and materials, from perforated plastic to woven fabric. They also offer protection against frost and wind.
Picture a bottomless wood-framed box with a hinged glass or clear plastic top. Now picture plants inside that box. These plant-protectors are called cold frames, and the clear top lets in ample sunlight to promote growth. The hinged top also opens, allowing ventilation and air for the plants to breathe. Cold frames offer more protection against frost than plastic mulches and row covers, but these babies can overheat if not monitored carefully.
Hoop houses, or high tunnels as we call them here at Wozupi, are temporary greenhouse structures with high ceilings. The metal frame is covered with a greenhouse-grade plastic, which allows us to tend to the crops even in the rain or snow. High tunnels extend our season by offering more consistent temperatures and growing conditions versus the unpredictability of the outdoor weather.