March is one of the most exciting — and most critical — months in the Southeast garden. You’re straddling two seasons at once: cool-season crops like broccoli and lettuce are hitting their stride, while warm-season transplants are waiting in the wings. Get the timing right this month, and you’ll have tomatoes, peppers, and squash rolling in by late May. Misjudge it, and you’ll spend June replanting.

Here’s a practical breakdown of what to plant in March across the Southeast, zone by zone.

Know Your Zone Before You Plant

The Southeast spans a wide band of USDA hardiness zones, and March timing varies significantly depending on where you live:

  • Zone 9 (Gulf Coast, South Florida border, southern Louisiana): Last frost has passed. You’re full speed ahead on warm-season planting.
  • Zone 8 (most of Alabama, Mississippi, Georgia, and the Carolinas’ interior): Expect your last frost between mid-March and early April. You can start some warm-season crops, but hold off on cold-sensitive plants until after that date.
  • Zone 7 (upper Southeast — northern Georgia, Tennessee border, upper Carolinas): Last frost typically runs through mid-April. Focus on cool-season crops now and start warm-season seeds indoors.

Not sure of your exact last frost date? Your county extension office keeps historical data and it’s worth looking up before you commit your transplants to the ground.

Finishing Up Cool-Season Crops

If you planted fall or winter crops, March is your last chance to squeeze out a harvest before heat shuts them down.

Broccoli and cauliflower are in their prime right now in zones 7-8. Harvest heads before they start to open or yellow — once temperatures push past 75°F consistently, the flavor turns bitter and the heads bolt. Side shoots on broccoli will keep producing for weeks after the main head is cut, so don’t pull those plants yet.

Lettuce, spinach, and arugula are racing the clock. In zones 8-9, direct-sow a final round of looseleaf lettuce in partial shade — morning sun and afternoon shade buys you an extra few weeks before it bolts. Spinach is especially heat-sensitive; pull it as soon as it starts to flower.

Kale holds up better than most brassicas in the spring heat and can be harvested all the way into early summer in zones 7-8. Let it keep growing while you shift focus to warm-season prep.

Peas are a true March star in zones 7-8. Direct-sow snap peas and shelling peas as early as the first week of March — they’ll mature in 60-70 days right as the weather turns warm. In zone 9, you may be too late; wait until fall.

What to Plant Outdoors in March

Zone 9 (Go for It)

March is full spring in the Deep South’s warmest areas. Get these in the ground:

  • Tomatoes: Set out transplants now. Bush varieties like Celebrity or Better Boy do well; cherry tomatoes like Sweet 100 are especially productive. Plant deep — bury the stem up to the lowest set of leaves.
  • Peppers: Wait until soil temperature reaches 65°F before transplanting. Peppers planted in cold soil stall and never quite recover.
  • Squash: Direct-sow summer squash and zucchini. They germinate fast and produce quickly — you’ll be drowning in zucchini by late April.
  • Cucumbers: Direct-sow or transplant. Get them on a trellis to keep fruit off the ground and improve airflow.
  • Beans: Direct-sow bush beans every two weeks for a continuous harvest. Don’t bother transplanting — beans grow best from seed sown right in the bed.
  • Sweet corn: Plant in blocks of at least 4 rows for good pollination. Succession-plant every 2-3 weeks.
  • Melons: Start seeds indoors or direct-sow if your season is long enough. Watermelon and cantaloupe need 70-90 days of warm weather.

Zone 8 (Transitioning)

Zone 8 gardeners are in that productive in-between state. Here’s how to work it:

  • Tomatoes and peppers: Start hardening off your indoor transplants now. Set them outside for a few hours each day, gradually increasing exposure over 7-10 days before planting after your last frost date.
  • Squash and cucumbers: You can direct-sow after your last frost date — or start transplants indoors now for a head start.
  • Beets: Direct-sow now. They’re borderline cool-season and handle light frost well. You’ll get a harvest before summer heat sets in.
  • Chard: An underrated crop that bridges the gap between cool and warm seasons. Plant now and it’ll produce straight through summer.
  • Herbs: Basil, cilantro, and dill all go in this month. Start basil indoors if you still have frost risk; the others can be direct-sown.

Zone 7 (Focus on Cool-Season, Start Warm Indoors)

If you’re in the upper Southeast, you’re still a few weeks away from your last frost. Use March wisely:

  • Direct-sow: Carrots, beets, turnips, radishes, kale, and Swiss chard all tolerate light frost and can go in the ground now.
  • Start indoors: Tomatoes, peppers, and eggplant should be started under lights if you haven’t already. At 6-8 weeks to transplant size, starting now puts you right at your last frost date for zone 7.
  • Peas: Get them in the ground as soon as the soil can be worked. They need cool temps to set pods and won’t perform well once summer heat hits.

Starting Seeds Indoors: What to Know

If you’re starting warm-season crops indoors, a few things will make or break your transplants:

Light is everything. A sunny south-facing window often isn’t enough for vigorous seedlings — you’ll get leggy, weak plants that struggle after transplanting. A simple grow light set 2-3 inches above the seedlings, running 14-16 hours a day, makes a huge difference. Check out our guide to starting seeds indoors for a full walkthrough.

Soil temperature matters more than air temperature. Most vegetable seeds germinate best between 70-80°F. A heat mat under your trays speeds germination dramatically and is worth the small investment.

Don’t overwater. Seedling damping-off — where young plants suddenly keel over at the soil line — is almost always caused by too much moisture. Water when the top of the soil is dry, not on a schedule.

Soil Prep for Spring Beds

If you haven’t already amended your beds, do it before you plant. The Southeast’s two most common soil challenges are red clay and sandy coastal soil — and both benefit from the same fix: organic matter.

Work in 3-4 inches of compost into the top 6-8 inches of soil. If you’re dealing with heavy clay, adding perlite or coarse sand along with compost helps drainage. Sandy soils benefit from compost alone — it acts like a sponge, holding moisture and nutrients that would otherwise drain straight through.

Also check your pH. Most vegetables prefer 6.0-6.8, and Southeast soils often run acidic. If your soil tests below 6.0, work in agricultural lime now — it takes 4-6 weeks to raise pH, so don’t wait. For more detail on getting your beds ready, see our guide to preparing Southeast garden beds for spring.

Watch for These Early-Season Pests

Warm March weather wakes up the pest population along with your plants. Keep an eye out:

Aphids cluster on the undersides of brassica leaves and on new transplant growth. A strong blast of water knocks them off, and ladybugs will follow once the garden ecosystem gets rolling.

Cutworms sever young transplants at the soil line overnight. Place a cardboard collar around transplant stems when you set them out — it’s the simplest and most effective prevention.

Flea beetles leave tiny holes in brassica and eggplant leaves. Row cover is the best protection while plants are young; most plants grow out of the damage once they’re established.

Plan for Succession Planting

One of the most common mistakes Southeast gardeners make is planting everything at once and then having a glut followed by nothing. March is a great time to think about succession planting:

  • Beans: Sow every 2 weeks from your last frost date through July.
  • Cucumbers: A second planting in late April or May will produce into fall after your first planting winds down.
  • Summer squash: Plant a second round in June or July for fall production.

Staggering your plantings means fresh vegetables from May all the way through first frost in November.

The Southeast’s climate is genuinely one of the best in the country for year-round vegetable gardening — long seasons, mild winters, and fertile soil. March is when that potential starts to pay off. Get your timing right, work with your zone rather than against it, and this will be your most productive spring yet.

Want a complete planting calendar and companion planting guide built for the Southeast’s unique conditions? The Harvest Home Guides eBook series covers every region with month-by-month planting schedules, soil advice, and pest management strategies written specifically for home gardeners.