What to Plant in March: Cool-Season Crops and Flowers

March sits in that narrow window where winter still has teeth but the soil is quietly waking up. Cool-season crops like spinach, peas, and kale can handle a light frost, making them ideal candidates for early outdoor sowing as soon as the ground is workable.

Meanwhile, warm-season seedlings like tomatoes and peppers need to get started indoors now so they're ready when your last frost date finally passes.

The difference between a productive spring garden and a frustrating one often comes down to a few weeks of timing. Knowing your local frost-free dates and matching your sow dates to soil temperature - not just the calendar - separates early harvests from repeated replanting.

March tasks split into two tracks: direct sowing outdoors for hardy crops, and indoor seed starting for warm-season vegetables that need a 6-8 week head start. Both happen in March, often at the same time.

This guide walks through both tracks, plus a zone-flex section to adjust timing for your specific region. If you want to see what comes right before this month, the February cold-hardy sowing options provide useful context for what's already in the ground.

Starting Vegetables in March

The first decision is whether your soil is actually ready. Squeeze a handful of garden soil - if it crumbles rather than clumps, it's workable.

If it smears like clay, wait another week or two before direct sowing anything.

Once soil is workable, cool-season vegetables go straight into the ground. Warm-season crops still need warmth indoors, with transplanting weeks away.

Your full-year planting calendar can help you map both tracks together.

Once your warm-season seedlings are established under grow lights or in a sunny south-facing window, check them daily. Leggy, pale seedlings mean insufficient light - move them closer to the source or add a supplemental grow light within the first week.

For anyone new to starting from seed, our guide on setting up an indoor seed station covers light setup, soil mix, and watering depth in detail.

Keep records of sow dates - you'll thank yourself when April arrives and you can't remember which tray is which.

Direct-sown root crops like carrots and beets need loose, stone-free soil at least 8-10 inches deep. Compacted or rocky ground causes forked, stunted roots.

Loosen it before sowing, not after.

Flowers and Herbs to Start in March

Herbs and flowers often get skipped in early spring planning, but March is genuinely useful timing for several of them. Fast-growing herbs like cilantro and dill bolt in summer heat, so starting them now gives you the best harvest window before temperatures climb.

Hardy annual flowers - snapdragons, larkspur, and sweet peas - actually prefer cool soil and can go out earlier than most gardeners expect. According to the UC Agriculture and Natural Resources guide, March is the right month to sow or transplant herbs like cilantro and parsley alongside edible greens such as spinach, beets, and peas.

In Western Oregon, OSU Extension's March calendar confirms that parsley, chives, and radishes can go in as soon as soil begins to warm.

Herbs that dislike root disturbance - dill, cilantro, and fennel - should always go directly into the ground. Skip the indoor-start step for these; transplant shock causes them to bolt almost immediately.

For flowers, the indoor-vs-outdoor decision usually comes down to frost tolerance. Snapdragons and pansies handle light frost well and can move outside sooner than most annuals.

Tender flowers like zinnias and marigolds are not March plants - hold those until May.

When you're planning what follows this spring planting push, reviewing what's worth sowing and transplanting in April helps you line up the next succession before this month's crops are even established.

The early-spring and late-spring calendars connect directly, and a gap between them is easy to create accidentally.

Seasonal Guides · See AlsoWinter Garden Planning: Catalogs, Layouts, and PrepWinters aren't for waiting - they're for mapping your spring harvest. While the beds sit empty and the...

Zone Flex: Timing by Region

USDA hardiness zones define average winter minimums, but your last spring frost date is what actually drives March planting decisions.

Those two numbers don't always match - a Zone 7 gardener in a low-lying valley may see frost two weeks later than a Zone 7 neighbor on higher ground.

• Zones 3-4 (Upper Midwest, Northern New England): Last frost typically falls in mid-May to early June. Most March work happens indoors - start tomatoes, peppers, and onions under lights. No direct sowing outdoors until late April at the earliest.
• Zones 5-6 (Mid-Atlantic, Midwest, Pacific Northwest inland): Last frost around mid-April to early May. Direct sow peas, spinach, and radishes outdoors in mid-to-late March. Start warm-season crops indoors now.
• Zones 7-8 (Pacific Northwest coast, Southeast, Lower Mid-Atlantic): Last frost often passes by late March or early April. Transplant cool-season starts outdoors, direct sow brassicas, and begin hardening off warm-season seedlings started in February.
• Zones 9-10 (California, Gulf Coast, Southwest): Frost risk is minimal. Transition away from cool-season crops as temperatures rise. Direct sow warm-season crops outdoors and watch for bolting in any greens already in the ground.

South-facing raised beds and beds near brick or stone walls warm up 1-2 weeks earlier than open ground. Use those spots for your first outdoor sowings and you'll consistently beat your neighbors' harvest dates without any extra effort.

If a late frost threatens after you've sown, a single layer of row cover fabric can protect plants down to about 24°F. Keep some on hand through March and April regardless of your zone.

For a broader view of spring garden prep tasks that overlap with planting decisions, the early spring soil prep guide covers bed readiness, amendment timing, and raised bed warming techniques. Gardeners who want the full arc from winter through spring will also find that looking back at the winter sowing options and then forward to what's ready to go in May helps build a connected planting schedule rather than isolated monthly decisions.

For a deeper comparison of how the spring-to-summer transition plays out crop by crop, the June warm-season planting breakdown shows exactly where March indoor starts land in the garden.

And our full monthly garden planning resources cover every month of the year if you want the complete picture.

Garden Plants · See AlsoBlack-Eyed Susan Care: Native Wildflower Growing GuideBlack-Eyed Susans light up borders and meadows from midsummer well into fall, delivering golden-yellow daisy-like blooms with dark...