First frost is upon us. To most gardeners this signals the end of the traditional gardening season. From last frost to first frost (basically Summer), most home gardeners focus their efforts on turning the soil and sowing their seed without giving much thought to the remaining months that lie on either side of these distinct weather events. However, there are those of us so inclined to eating fresh produce that we see the other 7 or 8 months of the year as a gardening challenge rather than a respite. This is how I came to be a full convert to the methods of season extension in the vegetable garden.
Growing up in Northern Wisconsin, my first introduction to season extension was the common bed sheet. As September crept in, my parents would watch the evening weather in anticipation of the forecast for over-night lows. Anything close to 32 degrees meant that we would be pulling the extra blankets and sheets from the closet and would spend our time after dinner covering as much of the garden as possible to protect our still ripening tomatoes and winter squash from settling frost. If the forecast looked especially dire, we would pull whole tomato plants and hang them in our basement near the woodstove to try and salvage the blushing fruit.
Season extension can be as simple as a small attempt to protect crops from first frost, or it can be as elaborate as building structures to offer growing spaces that are available for planting and harvest even in the dead of winter.
Here are a few of the techniques that we have used over the last decade to glean the most possible produce out of our seasonal gardens. Maybe you will find one of these ideas to be helpful to you.
Succession Planting- In its simplest terms, succession planting is the technique of sowing weather appropriate crops at the correct time of the year. When people visit our booth at farmers market in August and ask for spinach, I know that they do not understand the seasonality of their produce. Crops are used like a toolkit....some tools you only use once or twice a year (snap peas), other tools you may use all season long (beets). Knowing how your tools work is the fundamental basis for understanding succession planting. For example, some crops prefer to be planted only in spring and fall for optimal production (spinach or cilantro) and other crops are best planted after solstice to avoid bolting (daikon radish). As you come to know the growing habits of your favorite varieties, you can begin to take advantage of these characteristics to increase the over-all productivity of your garden. Whenever we have an empty space left by a preceding crop, we think about what the weather is like, how the light is changing and which ‘tool’ in our seed box would be the best match for the upcoming months. Utilizing this type of thinking has allowed us to harvest at the farm up to 11 months out of the year (even through several feet of snow if need be).
Structural Protection-Any type of structure that protects crops from excessive rain, wind or changes in temperature is nearly essential to true season extension. We are fortunate to have two large ‘high tunnels’ (metal framing with 6 mil clear plastic walls) to use at our farm for this job. In fact, growing eggplant and tomatoes in our side canyon would be nearly impossible without them. These structures allow us to begin sowing seed as soon as the ground is thawed in the spring and to continue to harvest even when the ground outside the structures is already frozen in the fall. In a home garden, this can be created using PVC piping bent into hoops with contractor’s plastic stretched over the top. Or even better would be bent electrical conduit (much more durable than PVC) for the hoops. There is no shortage of plans available on the internet for these tunnels and the amount of work required for setting them up or tearing them down is minimal versus their benefits. Hoop benders are available for purchase at a reasonable price through a number of reputable seed catalogs and can be shared with your friends or neighbors. In the Wenatchee region, one of the greatest advantages to this type of structure is the protection from spring winds. Newly set out seedlings can be stunted or broken by being wind-whipped when they are still young. With a little added protection, you can start your spring season earlier with a greater chance of success.
For further information on both succession planting and structural protection, I recommend reading The New Organic Grower and The Winter Harvest Handbook by Eliot Coleman. Both are quality reads. Happy Gardening!
WSU Chelan County Master Gardener and Co-Owner of Tierra Garden Organics in Leavenworth,Wa.