The beautiful thing about modern greenhouse and high tunnel technology is that your operation no longer has to stop or slow down during the long, cold winter months. But along with having a proper high tunnel winter growing setup in place before winter comes knocking, it's also crucial to have a planting schedule laid out so you can have the most successful winter harvest possible.
The key to good high tunnel winter growing is to give your plants a head start. Ideally, they should be close to maturity by the time the darkest period of the year (sometimes referred to as the "Persephone Period") begins. During this time, days drop to less than ten hours in length, so plants need to be hardy enough to weather the limited sunlight and frigid temperatures. Of course, your high tunnel structure will go a long way toward helping them survive and thrive as well.
Closely following an incremental high tunnel planting schedule will also give you a successful crop that lasts through the depths of winter. Staggering your sowings will cause crops to reach maturity at different periods and allow you to begin a new crop each time one is harvested, giving you a steady supply of produce until spring arrives. This will also give you the flexibility to handle potential crop failures and determine the best seeding dates for different crops, which can be applied to future seasons for even greater success.
There are two main categories of winter crops: winter-harvest and overwintered. Overwintered crops are usually planted out in the open and protected by low tunnels, so they remain in the open until they're ready to be harvested in early spring. Winter-harvest crops generally live their entire lives within high tunnels and are harvested throughout winter, so they will thrive the best with the incremental planting schedule described above.
Winter is different in the northern, southern, and western parts of the United States, and that has an effect on which plants will perform best in your winter greenhouse. The north has the coldest temperatures and shortest day lengths, while the south maintains warmer temperatures and day lengths over ten hours for much longer. The west tends to have more moderate temperatures throughout the year, especially on the Pacific coastline.
All these factors mean that crops must be planted at different times in summer and fall to reach the ideal level of maturity before winter.
If you haven't constructed your high tunnel yet, it would be a good idea to look into theSeasonal High Tunnel Initiative from the Natural Resources Conservation Service, a subset of the USDA. The program may be able to provide financial assistance to your operation, as long as you sign a contract stating that you will abide by certain growing practices for a set number of years (generally 4-10), after which point the high tunnel will be completely yours to do with as you please. The NRCS provides this assistance because high tunnels can help address issues in plant and soil quality, reduce the need for pesticides and limit the amount of energy consumption needed to produce a great harvest — all things that will lead to more environmentally friendly, sustainable growing.
Once you have your high tunnels constructed, there are a few other steps you should take to keep your plants cozy and protected. If you live in a northern area with severe temperature drops, adding extra row cover over your rows of plants will help protect them from frost. You can either use low tunnels or simply lay the covering directly over them, depending on the plant. This cover can be removed on warmer days to let the plants breathe and ensure they aren't getting too warm, which could inhibit their growth and encourage diseases.
It's also important to be mindful of how much you water your plants. It can be easy to overwater crops during wintertime, but underwatering is a concern as well. Using a moisture meter can be helpful in determining how much your plants will need.
Whether you're building your first high tunnel or are expanding your operation, Bootstrap Farmer has simple and affordableDIY greenhouse kits to suit your needs. Our high tunnel greenhouses are sturdy enough to weather even tough winter environments to keep your crops thriving and your business booming. Check out which offerings might be right for you orcontact us today for additional information.
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