What to plant in March in the US: by USDA zone

In the United States, knowing what to plant in March requires looking at your specific USDA hardiness zone rather than a single national date. Gardeners in northern zones 3 and 4 must focus on starting seeds indoors, while growers in southern zones 9 and 10 are already transplanting tomatoes and squash into outdoor beds. By aligning your planting schedule with local average frost dates, you can protect tender seedlings and maximize your regional growing season.

Zones 3–4: northern tier and mountains

In the coldest regions of the northern United States and high-altitude mountain areas, March is still dominated by snow, frozen ground, and sub-freezing temperatures. The average last spring frost in these zones does not arrive until mid-to-late May or early June. Outdoor planting is not yet viable, so activities are centered on indoor preparation.

1. Indoor sowing of slow-growing alliums

Onions, leeks, and shallots from seed require a long runway to develop substantial bulbs before the long days of summer trigger maturation. Sow these seeds indoors during early March under bright fluorescent or LED grow lights. Keep the soil mix moist and maintain temperatures around 65°F (18°C) for optimal germination. Trim the green tops back to three inches once they begin to lean to encourage strong, stocky root systems.

2. Sowing celery and celeriac indoors

Celery and celeriac are notoriously slow to start and require up to ten weeks of indoor growth before transplanting. Surface-sow the tiny seeds onto a moist, fine seed-starting mix, as they require light to germinate. Cover the seed trays with a clear plastic dome to maintain high humidity until the first green shoots emerge, then move them immediately under strong lights.

3. Setting up cold frames for hardy greens

If you have a protected cold frame positioned against a south-facing wall, you can prepare the soil by clearing away snow and laying down black plastic to absorb solar heat. In late March, if the soil inside the frame has thawed to a depth of three inches, you can sow spinach, claytonia, and mache. These cold-hardy greens will germinate slowly but will provide an exceptionally early spring harvest.

Zones 5–6: Midwest, Northeast, and Mid-Atlantic

For gardeners in the Midwest, Northeast, and Mid-Atlantic, March is a transitional month. While late-season snowstorms can still occur, the soil is beginning to thaw, and day lengths are increasing rapidly. The average last frost typically falls between mid-April and mid-May, making this the prime window for starting cool-season crops indoors and preparing the first outdoor beds.

1. Indoor starting of early brassicas and head lettuce

Sow broccoli, cabbage, cauliflower, kale, and head lettuce indoors during early to mid-March. These crops should be grown in modular cell trays to minimize root disturbance during transplanting. Keep them in a cool room, around 60°F to 65°F (15°C to 18°C), under bright lights to prevent them from becoming leggy. These transplants will be ready to go into the ground in mid-to-late April.

2. Direct-sowing hardy greens and peas outdoors

Once the soil has dried enough that it does not form a tight, sticky ball when squeezed in your hand, you can prepare outdoor beds for direct sowing. Direct-sow smooth-seeded shelling peas, sugar snap peas, radishes, spinach, and mustard greens. Consult the cool and warm season crops planting calendar to structure your crop successions correctly throughout the spring.

3. Planting bare-root fruit trees and small fruits

As soon as the ground can be worked without encountering frozen chunks of earth, plant bare-root fruit trees, cane berries, and grapes. Planting while the plants are still dormant allows their root systems to establish in the cool, moist spring soil before they must support new leaf growth. For detailed timing guidelines on establishing woody crops, refer to our analysis of plant fruit trees fall spring.

Zones 7–8: Upper South and Pacific Northwest

In the Upper South and the coastal valleys of the Pacific Northwest, March brings a distinct shift toward active spring growth. The average last frost occurs from late March to mid-April. Soil temperatures are rising consistently, allowing for a mixture of indoor warm-season seed starting and active outdoor direct sowing.

1. Indoor starting of warm-season nightshades

March is the critical window for starting tomatoes, sweet peppers, hot peppers, and eggplants indoors in zones 7 and 8. These heat-loving crops require six to eight weeks of indoor growth before they can be safely planted out after the last frost. Use a thermostatically controlled heat mat to keep soil temperatures between 75°F and 80°F (24°C to 27°C) until germination occurs, then move them to your brightest window or under dedicated lights. To plan your transplant dates accurately, use the guide on counting backward from frost.

2. Direct-sowing root crops and leafy greens

Direct-sow carrots, beets, Swiss chard, turnips, parsnips, and radishes directly into outdoor beds. Ensure the soil is worked to a fine, loose texture to allow straight root development. Covering the newly sown beds with a layer of lightweight horticultural fleece protects the seeds from heavy spring rains and prevents birds from eating the emerging sprouts.

3. Transplanting cool-season crops

Transplant established starts of broccoli, cabbage, kale, collards, and Swiss chard that were raised indoors during January or February. Water them in with a diluted organic liquid fertilizer to support root establishment, and keep frost cloth on hand to cover the young plants if an unseasonably cold night is forecasted.

Zones 9–10: Gulf Coast, Southwest, Florida, and California

For gardeners in the deep southern tier of the United States, the traditional spring planting season is already well underway or concluding in March. The danger of frost has passed in most of these regions, and the primary challenge is establishing crops before the intense heat of summer arrives.

1. Transplanting warm-season nightshades and cucurbits

Transplant tomatoes, peppers, eggplants, and tomatillos into their permanent outdoor positions. In these warm zones, early planting is essential to ensure fruit sets before summer temperatures rise above 90°F (32°C), which can cause blossoms to drop. Install sturdy support cages or trellises at the time of planting to avoid damaging growing root systems later.

2. Direct-sowing warm-season crops

Direct-sow warm-season crops directly into the warm garden soil. This includes bush beans, pole beans, lima beans, sweet corn, summer squash, cucumbers, and melons. Ensure these beds receive consistent moisture, as dry spring winds can quickly dehydrate the upper inch of soil where seeds are germinating.

3. Sowing heat-tolerant crops and preparing for summer

Traditional cool-season greens like spinach and head lettuce will bolt rapidly under the March sun in these zones. Switch to heat-tolerant alternatives such as Malabar spinach, New Zealand spinach, okra, and southern peas. For gardeners operating in arid southwestern climates, implementing water-conserving techniques is essential; review our guide on desert garden basics zones 9-10 to optimize irrigation and shading.

Essential March gardening jobs across the US

Regardless of your specific hardiness zone, completing these fundamental maintenance tasks in March sets a clean, structured foundation for the rest of the growing year:

1. Testing soil moisture and temperature

Working wet soil destroys its structure, compressing pore spaces and leading to hard, compacted beds that restrict root growth. Test your soil by digging up a handful from a depth of six inches and squeezing it; if it crumbles easily, it is dry enough to work. Use a soil thermometer to check the temperature at a depth of three inches; most cool-season seeds require a minimum temperature of 45°F (7°C) to germinate effectively.

2. Preparing and warming planting beds

Two to three weeks before you plan to sow seeds outdoors, clear away any remaining winter weeds or crop debris. Lay down clear plastic sheeting or black weed-barrier fabric over the soil. This traps solar radiation, raising the soil temperature by several degrees and drying out excess winter moisture so you can plant earlier in the season.

3. Applying mulch and compost

Apply a two-inch layer of well-rotted compost over your planting beds to replenish organic matter. For established perennial beds, fruit trees, and berry patches, apply a thick layer of clean straw, shredded leaves, or wood chips. This mulch suppresses spring weed seeds, regulates soil temperatures, and helps conserve soil moisture as the weather warms.