It was 18 degrees when I woke on September 19th.  There were some days that got down to 25 degrees previously, but that didn’t kill the tomato plants in the large cold frame that we have; 18 degrees did.  The tomato plants really were not planned and didn’t have the proper climate control, but it is a learning experience with some tomatoes as a bonus.

The kale, collard greens, broccoli, arugula, chard, and herbs are still thriving because they are hardy, cool-weather crops, the leaves grow quickly and they are in a small microclimate near our cabin.  The small garden was easy to give extra protection by adding a hooped, row-cover with gardening cloth over top. This was helpful this week when I was able to protect the plants from the hail storm as well.

There are many things that can be done to extend the growing season at our altitude, ranging from inexpensive solutions to more extensive infrastructure.  Easy and inexpensive strategies besides choosing cold-hardy plants include: choosing a protected location, using row covers and other small-scale plant protectors, heating up the soil, and applying thick mulch.

Observation and manipulation of microclimates around your property can significantly alter the growing season.  Choosing a site with southern sun, wind protection and cold air drainage are all important factors. A deciduous tree can offer shade in the summer and sun when its needed as well. If perennial plants are used, thick mulch can keep them protected in the winter.  The key is to walk the property and spend a lot of time observing and taking notes.

Putting row covers over the plants takes the most severe of the frost off, but does not drastically warm the temperature. They are helpful for many climate issues at this altitude because it can help warm the soil in the spring, protect from harsh afternoon summer sun and hail, and can provide a barrier for the frost.  These are easy to build with plastic tubing or wire arched over the garden area staked to the ground and a secured garden cloth over the top. Another inexpensive strategy especially in spring is to use Wall-of-Waters, to get plants started early and protect from frosts as the plants are surrounded by a one-inch protective circle of water tubes.  Even if it freezes, it still insulates the plant from the cold.

Doubling up efforts can make the biggest impact.  If the property has the space, a hoop house can offer larger-scale protection of a garden.  It is a medium-sized investment, the lower end roughly costing about $1,000 for a 16’x24’ hoop house, for example.  These structures have many of the same benefits of the row covers, but are more effective. Combining row covers within a hoop house doubles the benefits.  Hoop houses can be made into a greenhouse with climate control measures and additional insulation; however, other construction styles are more efficient for being a truly four-season greenhouse.

A geodesic-dome is the most energy-efficient greenhouse design.  The designs include the passive solar basics of absorbing sunlight, insulation, heat-absorbing mass, and ventilation.  These are able to offer year-round growing conditions even in the “Icebox”. They are made with polycarbonate glazing panels and are sturdy enough for winds and snow-load; however, they are also more expensive.

There are many options out there for season extension, and this article just lists a few.  In this climate, it is a critical to do something to protect the plants from the conditions.  The Community Garden in Fraser is a good place to go to see some of these strategies in practice.  Although there are challenges to grow food in this region, nothing is more satisfying or healthy for you and your family.  Happy growing Fraser Valley!


Robyn Wilson has degrees in International Business, Sustainable Communities, and Bilingual and Multicultural Education.  She teaches permaculture design at Colorado Mesa University, and returned to Grand County to manage the cabin community of Grandma Miller’s New Horizons.