The USDA Hardiness Zone 6 classification defines regions where the average annual minimum winter temperature falls between -10°F and 0°F. February marks a transitional period, but the last frost date is still weeks away, typically ranging from early April to early May. Outdoor planting is limited by frozen or saturated ground conditions during this late winter month. However, February is the necessary time for indoor preparations and the strategic planting of cold-tolerant materials to ensure a successful and timely harvest.
Seeds Requiring Early Indoor Start
February is the time to start seeds indoors for all crops that require a long growing season before transplanting outdoors after the final frost. Heat-loving vegetables, such as peppers and eggplants, demand a significant head start, often needing 8 to 12 weeks of indoor growth. These varieties will not mature properly during the Zone 6 growing season if they are sown directly into the garden later.
The seeds need consistent warmth to germinate effectively. A heat mat is often used to maintain soil temperatures around 75°F to 85°F, promoting rapid cell division and stronger root development. Once germinated, seedlings need a strong light source, such as a dedicated grow light, placed just a few inches above the plants. This supplemental light must run for 14 to 16 hours daily, preventing the young plants from stretching and becoming weak, or “leggy.”
Slower-maturing herbs also benefit from a February start, including parsley, chives, and oregano, which take time to establish a robust root system. Certain flowers, particularly perennial varieties like petunias, delphiniums, and snapdragons, often have a protracted germination period. Starting these flowers now ensures they are mature enough to produce blooms during their first year in the garden.
For long-season brassicas like broccoli, cabbage, and cauliflower, starting them in mid-February allows them to be hardened off and transplanted six weeks before the last frost. This timing helps them mature in the cool weather of spring. This prevents bolting, or premature flowering, which is triggered by high summer heat.
Direct Sowing Extremely Cold-Hardy Crops
While most of the garden remains dormant, a few crops can be directly sown into the ground in late February. This requires the soil to be “workable,” meaning it crumbles easily when squeezed and is not frozen solid or overly saturated with water. These direct-sown crops are chosen for their exceptional tolerance to cold soil and freeze-thaw cycles.
Peas are a prime candidate for direct sowing, as their seeds germinate in soil temperatures as low as 40°F, and the resulting seedlings can withstand light frost. Planting them early allows the plants to develop fully before the summer heat arrives, which can cause them to cease production. Similarly, onion sets and shallots can be planted as soon as the soil thaws enough to accommodate them. These alliums benefit from an early start to develop large bulbs.
Other cold-hardy vegetables, such as spinach, kale, and radishes, can also be sown now. Spinach requires cool soil, ideally around 45°F, to germinate successfully and will not sprout in warm summer conditions. To provide a buffer against sharp temperature drops and warm the soil, gardeners often use protective measures like low tunnels or floating row covers. This early planting allows for a harvest well before the warmer temperatures of late spring encourage these cool-season crops to bolt.
Installation of Dormant Stock and Tubers
February is the ideal window for planting material that is installed while completely dormant, taking advantage of the cool, moist soil before spring growth begins. Bare-root stock, which includes roses, certain fruit trees, and woody shrubs, are best planted now. The lack of leaves reduces transplant shock, allowing these plants to focus energy on root establishment in the cool ground.
Perennial vegetables, such as asparagus crowns and rhubarb roots, should also be planted as soon as the ground is workable. Asparagus crowns, which are mature root systems, benefit from early planting to establish their extensive structure for future harvests. Bare-root material should be planted immediately, or temporarily “heeled in” with moist soil or mulch if the ground is still frozen.
While the ground is still cold, various summer-blooming tubers and bulbs should be started indoors in pots to give them a head start. Dahlias and tuberous begonias are susceptible to frost, so they are planted in containers and kept in a cool, dark location until sprouts appear. Once growth begins, they are moved to a bright, warm location, developing robust plants ready for transplanting outdoors after the last frost.