“How can I maintain my garden all winter?”
I harvest lush greenery without a greenhouse all winter, so this is a frequently asked question with Zone 5 MicroCryla Merit. Of course, it’s important to choose the right cool seasonal crop. A medium frost blanket to warm my low tunnel a few degrees, just like mulch.
However, cold temperatures play a role in how much (or rather, less) the crop grows, but in reality the length of the day is important.
why?
Because, while you can change the temperatures outdoors in a greenhouse, a cold frame or a low tunnel, when it comes to growing vegetables, we are really at the mercy of the length of the day.
Most plants require at least 10 hours of light for active growth. When the length of winter days falls below this threshold, the plant’s growth slows to crawl and stops completely even at mild temperatures.
This period of decline is known as “Persephone Day” by Elliot Coleman, a leading expert at Winter Gardens. He named it after the Greek goddess of Persephone’s spring. That Persepoe has made the earth barren and seasonal changes thanks to its annual return to the underworld.
If your goal is a green and productive vegetable garden in winter, you can continue to earn the shortest seasonal days using Persephone Day to spend time planting from the nectar.
Calculate Persephone’s Day
Depending on where you are in the country, periods of sunlight that are less than 10 hours a day usually decrease between November and February.
You can check the exact date on the US Navy Observatory website. This website has an online tool to get a sunlight table (similar to the following) anywhere in the US.
If you are more visually prone to you and know your latitude, University of Nebraska Lincoln University has a neat little tool (example below) that allows you to explore the chart of the day length of your location throughout the year.
At my latitude in central Oregon, the Persepon period begins in the second week of November and ends in the first week of February. It’s solid growth for three months that doesn’t minimize plant growth, but you can continue picking the salad until you finally see more sun in early February.
How about that? By working in the opposite direction from the Persephone era.
Make the timing right
To enhance your winter vegetable garden, the plant must be at least 75% mature by the time the Persepon period begins. The farther along them, the more you can harvest them.
Most gardeners should make most of the planting from mid-August to mid-September, as most lush crops take about 50-80 days to mature. This may seem slow, especially when keeping temperatures and sunlight down on cool nights, but don’t forget to plant your winter garden and not for the fall harvest.
Related: These rapidly growing crops can be planted in the summer for autumn harvest
The plant grows slowly as it approaches the autumn equinox, but does not stop completely, so the vegetables continue to mature (though sloooowly) until early in spring.
If you sow seeds by mid-September, the warmth of summer and moderately long days usually result in faster germination and steady growth. Seedlings that have been started indoors can be transplanted between the present and early autumn while the soil is still warm.
However, if you missed this “deadline,” don’t be discouraged. I scattered Hardy Arugula and Asian green seeds under my low tunnels throughout the middle of October. They will only grow a few inches tall by late December, but they will provide delicious baby greens to my winter salad.
When sunlight falls below 10 hours a day, your garden slows down or virtual stops, it’s just a matter of protecting the plants from the elements. It’s like holding it in the outdoor “fridge” for the next four months, but in the meantime you can continue harvesting as needed.
Diversity is also important
Choosing the right cool season crops will make things much easier in your winter garden.
Plants that are naturally hard in winter are not a hassle when it comes to temperature. You don’t want to spend all your time decorating plants that can barely survive your hardiness zone. You want plants that not only survive, but also thrive in the cold, become more flavorful, and easily bouncing back in the spring.
Even our northern gardeners do well in the winter with many types of vegetables. I have written here before about some of my favorite ruthless crops, as well as crops that are magnificent tolerance to frost and freezing temperatures. (You might be surprised to learn how many people there are on that list!)
When growing climate-friendly varieties, you don’t need a greenhouse. A simple plastic or fabric row cover is enough to protect the plant from cold, dry winds (this is much more damaging than just frigid temperatures).
All of my winter vegetables tolerate low to teens (Fahrenheit) with occasional single digit nights. If your area has obtained consistent snow covering throughout the winter, you can also skip fabrics as the snow is insulated very well.
Starting in spring
Knowing your Persephone Day will help you plan ahead for spring.
If the length of the day increases to 10 hours at the end of winter, many zones may begin sowing seeds outside for cold hard crops such as peas, fava beans, salad greens, and root vegetables. (Here we have a list of other cool seasonal species that can be planted before the last frost.)
In central Oregon, seeds from the first round of mach, arugula and spinach are usually started in a low tunnel around the second week of February, just after the Persepon period has ended. All of these seeds germinate at cooler soil temperatures, so it’s just a matter of protecting young seedlings from hard freezes. (You can see a chart of the minimum germination temperatures of other seeds here.)
This is where some of my perennial crops (rhubarb, sea kale, soleil, enthusiasts, walking onion, chives, etc.) start to put out new shoots, and my wintering kale and chard resume growth. It’s so much fun to see the gardens come to life and the sudden growth encouraged as the sun rises on the horizon!
