By Lynn Byczynski
Spring weather can be highly variable, too rainy or hot or cold, and you may not be able to start crops when you would like. Overwintering is a strategy that provides a bit of insurance. With certain crops, you can seed in fall under Quick Hoops™ tunnels or in a hoophouse. The plants will either germinate in fall and go dormant, or the seeds will sit dormant over the winter. But, when conditions are right, they will come to life and grow rapidly. Overwintered veggies can be several weeks to months ahead of spring-sown crops.
Spinach is one of the best-understood crops for overwintering. It germinates well in cool soil, 45-75°F/7-24°C, so it can be planted several times in autumn. Depending on the weather, some plantings may reach a harvestable size in fall and then go dormant until spring. Other plantings may not germinate in fall but wait until late winter to start growing. Spinach is hardy down to 20°F/-6.7°C, which means it can be grown in the field in the South or in a hoophouse under an inner layer of row cover in many other places. The short days of winter may cause the spinach plants to stop growing, but if the plants are mature before short days arrive, it’s possible to harvest spinach all winter. Cold makes spinach incredibly sweet and succulent. The best varieties for winter production are ‘Tyee’, ‘Red Cardinal’, and ‘Python’.
Many other cold-tolerant crops are good candidates for fall planting and overwintering. They include arugula, beets, carrots, lettuce, onions, peas, and scallions. Always look for the most cold-hardy varieties of each crop. Direct seed in fall and watch them to determine whether they germinate then or in late winter. If they germinate and grow quickly, they may be killed by winter cold; in that case, seed later next year.