Extending the Growing Season

  • Difficulty Rating: Beginner
Extending the Growing Season

There is a season for everything. In life, as with gardens, we know this vividly and yet how often we try to defy the odds and accelerate the beginning of the gardening season, or attempt to push the limits on the back end.

Fortunately, there are some time-tested, easy to apply techniques that make extending the season more predictable and successful.

An easy place to start for pushing the growing season is to look for varieties that are considered “cold hardy”. Simply planting annuals or vegetables that have a higher tolerance to colder temperatures may be all that is required to buy some extra time for your plants. Most seed companies list this information routinely in catalogs and online.

Another technique I often use includes applying a thick layer of mulch around the base of all my plants. Not only does it keep the roots warmer, it also helps to maintain the soil temperatures at a more even level and can reduce the chances of the ground freezing or heaving. In some cases, as with spinach or strawberries, I’ll cover the entire plant in a layer of mulch to add an additional barrier of protection for the roots and foliage.

Physical barriers are an effective way to retain and capture a few extra degrees of heat while keeping season-ending frost off of the plants. Commonly referred to as floating row covers, the material is typically made of a lightweight spun bound fabric. The material is so light that it can actually be laid directly on the plants, so it appears to float. I prefer to support my row cover with metal wire or PVC pipes stuck into the garden beds. The row cover material is placed over the frame supports, a few inches to a foot above the plants. It is then pulled tightly and secured around all the edges with bricks, soil or whatever you may have that is convenient and sturdy enough to hold.

The row cover material allows light, water and air in but provide a protective barrier from frost and pests. When the sides are secured around the bed completely, several extra degrees of warmth can be retained and could make the difference in survival for marginally hardy plants.

Insulation is important for keeping plants safe. Blankets, plastic, buckets and the like can all serve to add critical protection on frosty nights. Be sure the covering protects the foliage by keeping frost off and that it extends all the way to the ground. This ensures that warmth from the soil is trapped which will add a few extra degrees under cover.

With the exception of row covers, whenever an enclosure is placed over your plant(s) at night, be sure to remove it the next morning or provide a way for the heat to escape. That same insulating barrier that keeps your plants warm and protected at night may be the very thing that cooks your plants the next day, especially with plastic. Direct sunlight and a covered plant can make for a deadly combination, even on a cold day.

Container-grown plants offer the maximum portability in allowing you to maneuver plants away from “Jack Frost”. Having the ability to move plants from the frigid outdoors to a protected shelter and back again can buy you several weeks or more of extended growing time.
Another technique is to locate tender plants in the most protected, yet sunny area of your yard. Referred to as “microclimates” because of their small, unique growing environment, these areas are often protected from wind, driving rain, frost or snow. This mini environment can potentially allow plants to survive outdoors when otherwise they might succumb to a killing frost or other harsh conditions. Microclimates provide not only protection from the elements, but when planted near a brick or stonewall, heat absorbed and retained during the day is released at night. Plants in close proximity will benefit from this exchange.

Cold frames are another way to provide protection in the fall. Think of a cold frame as a mini greenhouse. The basic premise is a solid, insulating barrier around the plants and a glass or plastic top that allows sunlight and heat in. All cold frames should provide a way for heat to escape during the day. Cold frames can be constructed from wood, cinder blocks, hay bales and more. A sufficiently insulated cold frame can even provide an environment warm enough to allow tender plants to thrive all the way until spring.

There is a season for everything, but it doesn’t mean you have to stop gardening just because temperatures fall. Extending the season is an exciting and rewarding endeavor made easier by knowing a few easy-to-apply techniques while giving you even more time to hone your skills come next spring.