After a winter spent eating store-bought salad greens, there is almost nothing more delightful than stepping out into the kitchen garden in March and uncovering a bed of ready-to-eat spinach. Overwintering this cold-hardy green is simple—the key is planning, and these easy-to-follow steps will yield a bountiful harvest of spinach come spring.
Cold-tolerant spinach varieties, such as 'Giant Winter' and 'Tyee', overwinter best if the plants are 3 to 4 inches wide by the time night temperatures start to dip toward freezing. Give the plants time to reach this size by sowing the seed 6 weeks before the average first-frost date. Spinach seed often suffers from spotty germination when planted in late summer and fall due to warm, dry soil conditions. Boost germination rates by cooling the soil the week before sowing; just water the bed well and then place a burlap sack over the soil to shade it.