ON MY CALENDAR, Halloween is a pivotal moment in the vegetable garden. Obviously, I’ll spend the day carving homegrown pumpkins. However, the spooky holiday also signals the end of the primary growing season.
Because of our latitude, Halloween just happens to correlate with the moment when the daylight dips below 10 hours per day each fall. When the days are this short, plant growth becomes imperceptibly slow or ceases altogether. Known as the Persephone period, after the Greek goddess who retreats to the underworld each winter, the span from late October to early March is generally a quiet time in the garden.
Many vegetable gardens are nearly empty by the end of October. It’s a good time to take stock of your remaining crops, and decide how and when to harvest and store them for the winter.
With appropriate storage techniques and a little bit of luck, you can continue to enjoy your fall garden produce even after the winter rains commence. The timing of your harvest and the best storage technique will depend on the crop and the space you have available. The most durable preservation techniques are canning, drying, pickling and freezing; the easiest technique is just plain storage at whatever temperature that crop prefers. I’d like to focus on the simple, yet subtle art of low-input crop storage.
Storage in the Garden
The simplest option is to do nothing, or virtually nothing. Some crops can be stored right in place and harvested through the winter as you need them. The success of your “garden refrigerator” will depend on the harshness of the winter and the microclimate of your yard. Most Seattle winters are mild, and Brassica crops such as kale and cabbage can live happily in the soil until March. However, every few years, we get an intense and extended cold snap, which can wreak havoc on otherwise-durable crops.
The exact location of your garden can have a dramatic effect on its ability to store crops overwinter. Two gardens in the same neighborhood might perform very differently during a cold spell. In a sheltered garden, all of the crops might be perfectly preserved. In a more-exposed site down the street, everything might be reduced to mounds of black slime. The more protected your garden is, the better your chances at keeping crops alive through the winter.
The best way to manage crops stored in the garden is to keep a close eye on the weather. If a long, cold period (under 20 degrees) is predicted, this might be a good opportunity to harvest your more-tender crops and cook them or store them in the “electric refrigerator.”
If you want to store root crops like carrots and potatoes outside, it is important to protect them from frost. The best way to do this is to cover the planting with a thick layer of mulch (8 inches or more). Rather than store root crops in the soil, I like to harvest them by the end of October. Due to our mild winters, some soil-dwelling insects stay active year-round. Bored and restless, these insects are likely to snack on tender carrots left in the garden. Even if the insect damage is minimal, these wounds make your roots highly susceptible to rot.
Crops you can store in the garden: Brussels sprouts, cabbage, carrots, cilantro, kale, potatoes, spinach.
Storage in the Refrigerator
The refrigerator is the safest place to store crops that like it cold (32 to 39 degrees) and humid (90% to 100% relative humidity). Placing crops in plastic bags will help maintain high levels of humidity. It’s unlikely your fall crops will be very dry when you harvest, but if they are, spray a tiny amount of water in the bag to help keep the humidity level up. When properly stored, some fall crops like cabbage and beets can keep in the fridge for several months.
Crops you can store in the refrigerator: beets, Brussels sprouts, cabbage, carrots, kohlrabi, radishes, turnips.
Storage on the Counter
If you are lucky enough to still have tomatoes coming off the vine, you can store them in a bowl at room temperature. Even green tomatoes will slowly ripen to red if harvested and left out this way.
Crops you can store on the counter: tomatoes, cured onions, garlic, winter squash.
Storage in a Root Cellar
While few modern homes are built with traditional root cellars, you might be able to simulate one in a corner of your basement or garage. The best location is one that stays cooler than the house but doesn’t get below freezing. Make sure the space is dark; this will discourage crops from sprouting.
A basement or heated garage works well for crops that need warmer temperatures and low humidity levels (potatoes, garlic, onions, sweet potatoes and winter squash). Store these crops in well-ventilated containers like wooden crates or perforated cardboard boxes.
An unheated garage or shed might be a good backup location if there is not enough room in your fridge to store the cold- and humidity-loving crops. Place these crops into plastic bags as if you were storing them in the fridge, and monitor the temperature to make sure it stays above freezing but below 50 degrees.
Wherever you decide to store your fall crops, make sure to check up on them every few days. Eat the lowest-quality produce first, and be proactive in composting anything that starts to rot. As the old saying goes, “One rotten turnip can spoil the whole barrel.”