3 Ways to Extend your Garden Season
In the Northeast region of the United States, the growing season always seems too short. How many times have you waited dangerously close to the first frost to see if those last few cabbage heads would develop? Or to snag a few more kale leaves? Or to pick that last carrot from the ground? Leave that hoping and fretting in the past, and take control of your final harvest with these three tips!
1) Get a Cold Frame
A cold frame is any covering for your crops, generally made of wood and glass, that will shield them from the decreasing temperatures while still letting in light and warmth. In cold frames, a mini greenhouse effect can occur, allowing the temperature to remain 5–10 degrees F warmer than the surroundings.
This 5–10 degree difference may not seem like much, but in fact it can make the difference between cold and freezing temperatures. This can give your plants the extra few weeks they need to finish maturing.
You’ll find all sorts of cold frames on the market, including ones made mostly of wood and ones made mostly of metal. All should have a transparent glass or plastic roofing. We’d recommend going with a wooden-glass combination as these are the sturdiest for long-term use. You can even find cold frame attachments which can be removed or added onto a raised bed when the days start getting shorter. See the following links for our recommendations in the low, medium, and high-budget range.
2) Mulch your garden soil
What is mulch you ask? “material (such as decaying leaves, bark, or compost) spread around or over a plant to enrich or insulate the soil.”
After the form and function of the cold frame, this low-tech option doesn’t seem like much, but mulching can make a big difference. Like cold frames, they can increase the soil temperature and extend the growing season for those critical few weeks.
According to a study from Govind Ballabh Pant University of Agriculture and Technology, soil surface temperature is increased by between 2.2 and 3.4 degrees Celsius (4 and 6 degrees Fahrenheit) when using black plastic mulch. Once again, this small difference in degrees and degree-days can mean the difference between a ripe, red tomato and a frosty green one.
This study actually used a black sheet mulch, which is not the most optimal of mulch. We recommend mulching using soil foods like the excess organic matter from your garden. For example, someone with fruit trees could use their pruned branches as mulch, while someone with a bumper crop of summer cucumbers could lay the pruned vines on the ground. These mulching techniques will not only increase soil temperature, but also soil fertility by contributing food to the soil microbiome. If you don’t have access to mulch in your garden, then you can order some, like this coconut mulch from Gardener’s Supply, or visit your local nursery.
3) Plant Cover Crops
Lastly, this tip is for people who have already made their last harvests, but don’t want to see their garden lay fallow all winter. Leaving any soil fallow is a fast-track to damaging your soil health, as the soil microbes will lose access to the base of their food web — plant root exudates (photosynthetic sugars sent by the plant into the soil).
That’s why we always recommend keeping a living plant in the soil, even through the harsh winter months. What crops could make it through the arctic vortex that is the northeastern winter? Cold-hardy cover crops of course! Last year, I planted a cold-hardy cover crop mix of hairy vetch (a legume with beautiful pink flowers) and winter rye grass. This mix allowed me to both fix nitrogen via the hairy vetch and generate a deal of organic matter via the rye grass.
Last February, I thought my cover crops were doomed when the snow piled up on top of them and covered them up entirely, only to find that they popped right back up in March when the snow melted. This mix truly does the phrase “cold-hardy” justice. However, even less cold-hardy cover crop mixes can serve a similar purpose. Plant autumn cover crops like peas and oats and allow them to grow through the short fall season. If you get heavy snows, they will be buried and die, but their usefulness won’t end there, as they’ll serve as a natural mulch to armor your soil until spring rolls around, at which point you can easily plant or seed directly into the natural mulch layer.
We hope that these three tips will help you continue to grow your favorite crops right up until the first frost, and even through it!
