March serves as the bridge between winter dormancy and the active growing season, making it a month of transition for gardeners. Fluctuating temperatures and increasing daylight signal the shift from planning to preparation, laying the groundwork for a successful harvest. Success relies on timing foundational tasks correctly to capitalize on the changing weather patterns.
Essential Pre-Season Preparation
Before any seeds are sown, focus on infrastructure and existing perennial life. Take inventory of garden tools, ensuring shovels, trowels, and pruners are cleaned and sharpened. Check irrigation systems for winter damage and clear debris from beds that could harbor pests or diseases.
Soil health requires attention, often beginning with a soil test to determine pH level and nutrient composition. Most garden plants thrive in a pH range of 6.0 to 7.0, and knowing specific needs allows for targeted amendments. If the soil is workable—meaning it crumbles when squeezed—incorporate aged compost or manure to improve texture, water retention, and nutrient availability.
Dormant pruning must be completed before buds begin to swell and new growth starts. Prune deciduous fruit trees, such as apples and pears, along with roses, to remove dead, diseased, or crossing branches. This removes branches that impede airflow and light penetration, focusing the plant’s energy on producing strong, healthy new growth.
Indoor Seed Starting and Hardening Off
March is the ideal window for starting warm-season crops indoors to give them a head start before the last expected frost date. Tomatoes, peppers, and eggplants require a long growing season and are typically sown indoors six to eight weeks before safe transplanting. Starting these heat-loving plants inside ensures they are mature enough to fruit when outdoor temperatures are consistently warm.
Maintaining the correct indoor environment requires consistent warmth and strong light for robust seedling development. Seedlings benefit from temperatures around 70–75°F for germination, followed by slightly cooler temperatures once they sprout. Using grow lights positioned just inches above the young plants prevents them from becoming tall, weak, and “leggy.”
The transition from the protected indoor environment to the outdoor world is managed through hardening off. This procedure gradually exposes seedlings to sunlight, wind, and cooler temperatures over seven to fourteen days to prevent transplant shock. Start by placing trays outside in a shaded location for an hour or two, slowly increasing the duration and exposure to direct sun each day. Seedlings are ready for final planting once they can tolerate full days without wilting.
Direct Sowing and Transplanting Early Crops
Once the soil is workable, March welcomes the planting of cool-weather crops that thrive in the early spring chill. Direct sow seeds for vegetables like peas, spinach, radishes, and lettuce, which can germinate in soil temperatures as low as 40°F and tolerate light frosts. Succession planting—sowing a small batch of seeds every two to three weeks—will ensure a continuous harvest before the summer heat causes these crops to bolt.
March is the deadline for planting dormant bare-root stock, such as asparagus crowns, rhubarb, and berry canes, before they break dormancy and begin active growth. These plants are best established now while dormant, allowing their root systems to settle into the soil. Bare-root stock should be kept moist until planted, and the planting hole must accommodate the spread of the roots.
Cool-season transplants, including cabbage, broccoli, kohlrabi, and onion sets, can be set out well before the last frost, as they are significantly more cold-tolerant than warm-season crops. To push the planting timeline and protect emerging plants, consider using season extension aids like floating row covers. Lightweight row covers provide 2–4°F of frost protection while allowing light and water to penetrate, shielding young plants from wind and pests.