15 Vegetables to Start Seeding in March

March is the perfect month to start seeding certain vegetables through indoor sowing, winter sowing, or even direct seeding in warmer hardiness zones. In this article, gardening expert and former organic vegetable farmer Logan Hailey shares her favorite vegetables you can start planting in March!

Vegetables growing in garden in March

Contents

Spring is on the horizon, but the nighttime temperatures can still be fairly chilly. March is an auspicious and exciting time in gardens across the Northern hemisphere. Depending on your growing zone, you may be starting warm-weather veggies indoors or planting your first hardy crops out in the garden.

You can get a head-start on tomatoes and peppers and establish cool-weather peas, greens, and roots so they can sweeten in the light spring frosts. You may even be able to plant early potatoes and onion sets!

Let’s dig into the best vegetables to seed in March based on your hardiness zone, as well as the best method to start seeding them this season!

What Vegetables Should I Start in March?

March is the best time to establish cold-hardy crops outdoors and get a head start on warm-weather crops indoors. In the garden, you can direct seed beets, radishes, turnips, lettuce, endive, spinach, kale, sugar snap peas, and spring onions. In your greenhouse or windowsill, March is the ideal time to establish broccoli, cauliflower, tomatoes, peppers, eggplant, and squash in seedling trays.

There will be variations in seeding times based on your growing zone, but a general rule of thumb is: When the daffodils bloom, it’s safe to start seeding cool-weather crops outdoors! Most roots, greens, and alliums can go into the ground a little before the expected last spring frost.

Quick Reference: Average Last Frost Dates by Zone

USDA Growing Zone Average Last Spring Frost
Zones 1-3 May
Zone 4 Late April to Early May
Zone 5 Mid-April
Zone 6 Early to Mid-April
Zone 7 Late March to Early April
Zone 8 Mid-March
Zone 9 Mid-to-late February
Zones 10-12 No frost

Growing zones are calculated based on historical weather data from the NOAA National Centers for Environmental Information. To find the most precise estimated last frost date, use this tool from Farmer’s Almanac.

Spring Vegetables for March Planting

As northern growers coax their frigid gardens to awaken, southern soils are bursting with spring life. March is an exuberant time for seed starting indoors and out. Planting these 15 spring veggies will set you up for hearty yields later in the season.

Pro Tip: Always check the soil temperature before planting. Ambient temperature and regional last frost dates are excellent tools, but they do not guarantee seed success. The best way to determine your planting dates is with real data from your own garden.

Spinach

Close-up of spinach growing in a sunny garden. Spinach has beautiful oval, bright green, glossy leaves with smooth edges.
This is a popular cold-hardy crop whose leaves become tender and sweet due to cold evening temperatures.
  • Soil Temperature: 45-70°F
  • Seeding Rate: 3-5 seeds per inch in rows 2-4” apart
  • Start Indoors in These Zones: N/A – Not usually started indoors.
  • Start Outdoors in These Zones: Zones 3-9, as long as the ground is thawed.

Spinach is the quintessential cold-hardy garden crop that can survive some frigid weather. In the early spring, it truly springs up without hesitation. Spinach prefers chilly nights and grows the most tender, sweet leaves before summer’s heat.

Of course, it still enjoys some cozy comfort during the germination phase. Ensure that the soil temperature is above 40°F before seeding outdoors. The soil needs to be fully thawed and easily workable. Use clear plastic or row cover to warm the soil surface.

You can plant several successions of spinach by seeding every two weeks from early March through May. For the earliest planting, choose a hardy savoy variety like ‘Kookaburra,’ ‘Hammerhead,’ or ‘Emperor.’ Harvest smooth-leaf varieties like ‘Auroch’ or ‘Gazelle.’ as baby spinach for delicious spring salads.

For late March plantings in warmer climates, choose a heat-tolerant and bolt-resistant variety like ‘Teton’ or ‘Lizard.’

Arugula

Close-up of growing arugula in the garden. The plant has a rosette of basal leaves, deeply lobed, dull green in color.
Arugula is a fast-growing spring salad that loves cold weather.
  • Soil Temperature: 45-70°F
  • Seeding Rate: 5 seeds per inch in rows 2” apart
  • Start Indoors in These Zones: Direct seeding is recommended.
  • Start Outdoors in These Zones: Zones 3-9, as long as the ground is thawed.

If you’re feeling impatient as you wait for spring, baby arugula provides quick gratification. This peppery green germinates very quickly and doesn’t mind cool soils.

Because arugula adores chilly weather, it is the perfect fast-growing spring salad green. As long as it is grown in full sunlight, arugula can yield in less than 3 weeks and will keep growing back after each cut.

Like spinach, arugula will rapidly bolt in hot weather. Thankfully, the flowers are edible and delicious. Varieties like ‘Astro’ and ‘Runaway’ are adapted to cold springs while remaining bolt-resistant in warmer climates.

As spring weather warms, arugula becomes more prone to attack from pests. Flea beetles are a major problem with this early green because they emerge from dormancy at around the same time arugula is planted. I always recommend covering arugula with row fabric immediately after sowing.

Onions

Close-up of a growing onion in a sunny vegetable garden. Onions are round, brown-skinned vegetables that grow underground. The leaves are bluish-green in color, long, fleshy, hollow, with one flattened side.
March is a great time to start growing onions from seed indoors.
  • Soil Temperature: 45-85°F
  • Seeding Rate: For onion sets, plant 1-2” apart in rows 12-15” apart. For onion seeds, sow in clumps of 5 seeds per plug cell. Thin to 3 per cell and transplant about 6” apart.
  • Start Indoors in These Zones: Zones 2-5 can start storage onions in flats indoors.
  • Start Outdoors in These Zones: Plant onion sets outdoors in zones 4-6. Direct seed in zones 7-12.

Most allium-family crops enjoy cool weather. But they also take a long time to establish. From red onions to sweet onions to storage onions to green onions (scallions), March is the time to get these kitchen staples rooted!

For a jumpstart on your onion harvest, I recommend planting onion sets rather than onion seeds. Onion sets are like pre-grown baby onion bulbs that rapidly grow into green onions (also known as scallions). They are available at most garden stores.

You can put them in the ground several weeks before the last frost as long as the ground is thawed and nighttime temperatures stay above 20°F. Scallions will be ready in as little as 5-6 weeks, or you can wait another 2-3 months for large cooking onions.

If you want to grow onions from seed, March is also the ideal time to start those indoors. Like their leek cousins, storage onions have notoriously long days to maturity.

Requiring up to 100 days to mature, March is a great time to establish storage varieties in short-season areas. Sow in open flats or cell trays so they can be transplanted out when they reach 5-6” tall.

Brassicas

Close-up of a growing cabbage in the garden. Two large cabbage heads consist of densely packed, round, waxy, succulent, white-veined grey-green leaves.
Brassica is recommended to be planted indoors in February or March and transplanted into the garden by April.
  • Soil Temperature: 60-80°F
  • Seeding Rate: Sow brassicas at 2 seeds per cell in 72-cell flats or 6-packs. Thin to 1 per cell. Wait 3-4 weeks to transplant outdoors about 12-24” apart (depending on variety) in rows 18-36” apart.
  • Start Indoors in These Zones: Zones 3-7
  • Start Outdoors in These Zones: Zones 8-10. Direct seeding is not common for brassicas.

The Brassicaceae or Brassica family includes broccoli, cauliflower, cabbage, brussels sprouts, collard greens, and broccolini. While each of these crops has individual quirks, they are typically seeded and transplanted in the same way.

Most northern growers seed their brassicas indoors in February or March, so they are ready to transplant by April.

Count back 6- 9 weeks from your last frost date to determine the ideal indoor sowing date. In cold zones, look for early and midseason varieties. In southern climates, you will want a heat-tolerant variety that can withstand the warmer spring temperatures.

Southern growers who forget to seed brassicas in February or March should wait until late summer to start fall varieties.

Even though brassicas can handle cool weather, they still prefer warm soil to germinate. This is why transplanting is most common for all of these crops. Strong transplants have much higher survival rates and yields than direct sown broccoli, cauliflower, etc. 

Lettuce

Close-up of a lettuce growing in the garden beds. The plant has large rosettes of rounded, large, bright green leaves with a wrinkled structure.
Lettuce germinates well in soils up to 40°F.
  • Soil Temperature: 40-68°F (optimal is 60-68°F)
  • Seeding Rate: For baby leaf lettuce, sow 4-6 seeds per inch in rows 2” apart. For transplants, sow 1-2 seeds per cell, harden off after 3-4 weeks, and transplant 8-10” apart in rows 12-18” apart.
  • Start Indoors in These Zones: Zones 3-7
  • Start Outdoors in These Zones: Zones 5-10

You can never go wrong growing lettuce and baby salad greens! In zones 7-10, you can maintain a continuous year-round supply of salad. In colder zones, lettuce doesn’t mind germinating in soils as cold as 40°F. Lettuce seeds enter “thermal dormancy” in warm soils over 70°F, which means they won’t germinate at all. 

There are lots of options for spring lettuce:

Lettuce Quick Harvest

For the quickest harvest, sow lettuce close together as baby greens and cut them in as little as 2-3 weeks.

Direct Sown Head Lettuce

For directly sown head lettuce, soils need to be at least 40°F, and you will need to wait around 40-50 days.

Seeding Head Lettuce Indoors

If you seed lettuce indoors and transplant outside, the transplants can handle ambient air temperatures as cold as 20°F.

Swiss Chard

Close-up of a Swiss Chard growing in a sunny garden. The plant has broad, shiny, dark green leaves with pronounced ribbing and strong, crisp, red stems.
Swiss Chard germinates in warm soil and tolerates light frost well.
  • Soil Temperature: 40-90°F
  • Seeding Rate: Sow 2-3 seeds per cell and thin to 1-2 plants per cell. After 5-6 weeks, transplant out 4-6” apart in rows 12-18” apart. Direct seeding rates are around 6 seeds per foot, ½” deep in rows 12-18” apart.
  • Start Indoors in These Zones: Zones 3-8
  • Start Outdoors in These Zones: Zones 9-12

Chard is widely adaptable and not as finicky as other cool-weather greens. However, it loves warm soil and experiences optimal germination at around 85°F.

The seedlings tolerate light frosts, but they can’t handle anything too harsh. This means that chard seeding is best reserved for indoor cell trays or outdoor sowing in late March.

If chard seeds are exposed to prolonged temperatures below 50°F, they become more prone to bolting. Row cover or a cold frame can help keep them cozy in their early life so they can yield all summer long.

Kale

Top view, close-up of a growing Kale on a raised bed in a garden. The plant has a beautiful rosette of long, oval, blue-green leaves with heavily frilly, curly edges.
This cold-hardy brassica prefers soil temperatures above 75°F for germination.
  • Soil Temperature: 50-80°F
  • Seeding Rate: For baby greens, seed 3-4 seeds per inch, ½” deep, in rows 2-3” apart. For transplants, sow 2 seeds per cell and transplant outdoors in 4-6 weeks about 12-18” apart in rows 18-36” apart.
  • Start Indoors in These Zones: Zones 3-8
  • Start Outdoors in These Zones: Zones 9-10

Kale is infamous as a winter green, but it also does phenomenally well in the spring. Baby kale mixes provide some of the first salad harvests for northern growers, while full-grown plants are common in temperate zones.

If you didn’t overwinter kale, March is the perfect window of opportunity to start kale plants that will last you all season long. You plant this green throughout early spring, summer, and up to 3 months before the expected fall frost.

Like its brassica cousins, kale is cold-hardy but it prefers soil temperatures over 75°F during germination. Unless you are growing baby greens, kale does best as a transplant with row cover protection. Unfortunately, kale is not recommended for subtropical climates due to the heat and pest pressure.

Carrots

Close-up of a gardener's hands in gray gloves holding freshly picked carrots against the backdrop of a green garden. Carrots have an edible orange-colored taproot with a pointed tip. The plant also produces a rosette of 8-12 dark green, thin, strongly lobed, dill-like leaves above ground.
Garden carrots must be sown directly into the ground and ensure soil temperatures are above 65°F.
  • Soil Temperature: 60-85°F
  • Seeding Rate: Sow ¾” to 1” apart, ¼” to ½” deep, in 2” wide bands about 12” apart. Do not sow too densely or the carrots will not grow thick enough.
  • Start Indoors in These Zones: N/A
  • Start Outdoors in These Zones: Zones 5-12

Carrots are slow to germinate in cold soils, yet they get exceptionally sweet when nighttime temperatures hover around 40°F. So how do you find a happy medium? In zones 5-7, you can sow carrots in late March by using a special soil warming trick:

  • Grab a black tarp or piece of clear greenhouse plastic.
  • Weed and prepare a seedbed, then lay the plastic flat over the surface.
  • Hold it down with rocks along the edges and wait a few days to a week. This will create a mini-greenhouse effect that harnesses the sun’s warmth. Raised beds also warm more quickly.
  • Check that the soil temperature under the plastic is above 65°F.
  • Sow your carrots and then cover them with a thick row cover (translucent) to keep them warm, protected, and evenly moist until germination.

Zones 8 and warmer can usually sow carrots outside in March without any extra soil-warming measures.

Although some root crops (like beets and turnips) can be transplanted, carrots absolutely must be direct sown. Their tap roots are highly sensitive to disturbance and cold. If your soil isn’t warm enough, it’s best to wait until April. Choose a robust early carrot variety like ‘Mokum’ or ‘Scarlet Nantes.’

Beets

A close-up of a ripening beetroot in a garden bed. Beetroot has a large, round, fleshy, purplish-pink edible root with a thin, smooth, dark purple-grey skin. The vegetable produces a beautiful rosette of bright green smooth glossy leaves with strong crunchy purple stems.
Plant your beets before the expected last spring frost with soil temperatures above 50°F.
  • Soil Temperature: 60-80°F
  • Seeding Rate: Sow 15 seeds per foot, ½” deep, in rows 12-18” apart. Thin to 1 plant per 2”. If transplanting, sow 2-3 seeds per cell in cell trays and transplant out 3” apart in rows 12-18” apart. Selectively harvest larger roots from each bunch while holding the others in place so they can grow longer.
  • Start Indoors in These Zones: Zones 3-5
  • Start Outdoors in These Zones: Zones 6-12

If you cranked through all your winter storage roots, you may be craving some hearty spring roasts. You can direct seed garden beets up to a month before your expected last spring frost as long as the soil is above 50°F. These robust roots tolerate frosts, but they will not produce bulbous roots if the soil is too cold. Hard frosts will kill young plants.

If you want to harvest beets more quickly, consider starting them indoors. This may seem weird since most root crops have to be directly sown. But beets are unique because their hardy roots don’t mind a little disturbance.

In fact, these chard cousins can be seeded in bunches of 2-3 inside cell trays and transplanted out about 5-6 weeks after heavy frosts subside. This is a great way to ensure even stands and get the most out of your beet seeds.

Snap or Snow Peas

Close-up of ripening Snow Peas in the garden. Pea pods are flat, thin, bright green in color with bulges due to ripening seeds inside. The leaves are oval, bright green, smooth.
Snow Peas is great for March sowing when the soil is completely thawed.
  • Soil Temperature: 50-85°F
  • Seeding Rate: Sow 1-2” apart, 1” deep, in rows 18-24” apart, or on each side of a trellis.
  • Start Indoors in These Zones: Zones 2-4
  • Start Outdoors in These Zones: Zones 5-11

Can snow peas really withstand snow? Unfortunately, not. But most types of peas are surprisingly hardy and eager to please in the cool temperatures of March! You can seed peas as soon as the soil can be worked.

Whether you choose snap peas or snow peas, be sure that the ground has thoroughly thawed and that you have installed a trellis for them to climb. The easiest trellis is composed of trellis netting or chicken wire secured between two T-posts.

It’s always best to install a trellis before you seed. Peas can also be sown indoors and transplanted for a head start, but this is only necessary in ultra-cold climates.

Peppers

Close-up of a ripe bell pepper in the garden. Bell pepper plants are short shrubs with alternate, elliptical, smooth-edged, bright green leaves. The berries are large, bright red, juicy, crispy with a shiny skin.
Peppers seeds are best grown in greenhouses or indoors and transplanted into the ground in April.
  • Soil Temperature: 75-90°F
  • Seeding Rate: Seed 1-2 seeds per cell or 6-pack about ¼” deep. Optionally, up-pot to 4” pots once true leaves appear. Transplant after 8 weeks when outdoor soil has warmed to at least 75°F. Space pepper plants 12-18” apart in rows 24-36” apart.
  • Start Indoors in These Zones: Zones 5-9
  • Start Outdoors in These Zones: Direct seeding is not recommended. Seedlings can be transplanted outdoors in March in zones 10-12.

Most peppers are long-season, hot-weather crops that demand to be started indoors. Northern gardeners don’t usually have enough frost-free days to warrant seeding these nightshades outdoors. Moreover, studies show that transplanted peppers will yield earlier and in greater abundance.

As tropical natives, peppers have absolutely zero tolerance for the cold. Seeds refuse to germinate in chilly soils and the plants can be pretty pathetic if air temperatures drop below 55°F.

For the best results, place a germination heating mat underneath pepper trays. Unless you have a greenhouse, far-northern growers may want to wait until April to start their peppers.

Tomatoes

Close-up of a ripe tomato bush in the garden. The shrub has climbing stems covered with bright green lobed leaves and oval, soft berries covered in thin glossy skins in green, orange and red depending on the stage of maturity.
Tomatoes are a heat-loving crop that thrives in warm indoor spaces during the early stages of growth.
  • Soil Temperature: 75-85°F
  • Seeding Rate: Seed ¼” deep in cell trays or flats. Once they have true leaves, up-pot to 3” or 4” containers. Grow at a constant 60-70°F, using heating mats, supplemental lighting, and/or row cover for protection. Transplant deeply in the soil after 6 weeks when outdoor air temperatures are consistently above 45°F. Spacing depends on variety.
  • Start Indoors in These Zones: Zones 5-9
  • Start Outdoors in These Zones: Direct seeding is not recommended. Seedlings can be transplanted outdoors in March in zones 10-12.

Start tomatoes about 5-6 weeks before your expected last frost. Like their pepper cousins, tomatoes are another heat-loving crop that flourishes in warm indoor growing spaces during the early stages of growth. These garden favorites adore a cozy root zone with soils at least 70°F (ideally warmer).

Provide tomatoes with an abundance of sunlight (in a greenhouse) or supplemental lighting that is close to the plants. Some gardeners start the lights hovering over the seed trays and then raise them as the plants grow. This encourages robust root growth rather than spindly stems. If you are growing by a window, be sure that there is an abundance of warmth and light.

Beware! You don’t want to start growing tomatoes from seed too soon! They can easily become leggy or rootbound if they are left in containers for too long while you wait for the weather to warm.

Like peppers, northern growers in zones 4 and cooler usually wait until April to seed tomatoes. For best results, these tropical natives should never be exposed to temperatures below 45°F.

Squash

A close-up of a ripe zucchini in a sunny garden. The vegetable is large, long, cylindrical, bright yellow. The leaves are thick, dark green, large, palmately lobed, and the stems and leaves have small spiny trichomes.
It is recommended to sow squash seeds 3-4 weeks before the expected last frost.
  • Soil Temperature: 77-95°F
  • Seeding Rate: Depends on variety.
  • Start Indoors in These Zones: Zones 7-10. Colder zones should wait.
  • Start Outdoors in These Zones: Direct seed in zones 10-12.

You can begin seeding squash plants about 3 to 4 weeks before your expected last frost. While every variety has its nuances, these guidelines apply to most types of Cucurbits (squash, melon, and cucumber family crops).

Summer and winter squash can be a bit confusing because they both technically grow in the summer. In fact, most varieties start in the spring. Zucchini and pumpkins are often planted right around the same time!

Squash should only be seeded indoors in late March for zones 7 and warmer. If you seed squash too early, the fast-growing plants risk over-growing their containers or becoming rootbound and sensitive to transplant shock. Only tropical and subtropical gardeners can plant squash outside this early in the spring.

Turnips

Close-up of a gardener's hand holding a bunch of freshly picked turnips against a green garden blurred background. The turnip has round, edible white roots with purple tops. Plants form long, crunchy, purple-colored stems with light green, hairy leaves.
Turnip is a cold-tolerant crop that is not afraid of frost.
  • Soil Temperature: 50-70°F
  • Seeding Rate: Sow in 2-4” wide bands, about 1-2” apart (depending on desired size), ¼” to ½” deep, in rows 12-18” apart.
  • Start Indoors in These Zones: Transplanting is not recommended.
  • Start Outdoors in These Zones: Zones 8-10

Early March is a welcoming time for turnips. These tasty roots offer edible greens and impressive cold tolerance. They enjoy the cold weather and seedlings don’t mind light frosts. Direct seed into your garden about 2 to 3 weeks before your average last frost date. Use row covers to protect from flea beetles and chilly nights.

If you hate the pungent taste of purple top turnips, try a sweet, crisp salad turnip-like ‘Hakurei’. These Japanese-style turnips can be eaten raw, grow very quickly, and are super refreshing on warm spring days!

Potatoes

Close-up of ripe potatoes on the soil in the garden. Potatoes are oval, edible, firm fruits covered with a thin, light brown skin.
Potatoes can be planted in March in zones 8-10.
  • Soil Temperature: 45-55°F
  • Seeding Rate: Plant seed potatoes with eyes facing up about 2-3” deep in the soil. Most varieties can be spaced 12” apart in rows 24-36” apart.
  • Start Indoors in These Zones: Pre-sprout potatoes indoors in zones 7-8. You can also try growing potatoes in pots.
  • Start Outdoors in These Zones: Zones 8-10

Spring or “new” potatoes are highly coveted in the culinary world. They are buttery smooth and oh-so tender, but their skins are very fragile during transport, which means they’re rarely available in grocery stores. No wonder early spring potatoes are such a delicacy!

Potatoes are warm-loving members of the Solanaceae (nightshade) family, but they don’t do as well in the extreme heat of the tropics. Only zones 8-10 can plant potatoes in March. Colder zones should wait until April or May.

Final Thoughts

The month of March is when many gardeners are starting to sow indoors or put seeds in the ground in warmer climates. If you haven’t started picking the types of vegetables to grow this season, any of those on this list will make fine picks for March plantings. March is a great month to get an early start on your vegetable garden in colder climates or get seeds in the ground for a bountiful spring harvest.

SHARE THIS POST
Vegetables in the garden in the month of February.

Vegetables

11 Vegetables to Start Seeding in February

February is a great month to start getting your favorite vegetables winter sown, into containers, or even into the ground in warmer climates. In this article, gardening expert and former organic vegetable farmer Logan Hailey walks through 11 popular vegetables you can start planting this February in anticipation of spring!

august crops

Vegetables

21 Crops to Plant in August for Fall Harvests

Are you unsure of which crops to start seeding in the month of August? Believe it or not, August is a great month to start seeding crops for fall harvesting. In this article, gardening expert and former organic farmer Logan Hailey shares her favorite crops to put into the ground starting in August for a great fall harvest.

august vegetables

Vegetables

21 Herbs and Vegetables To Plant This August

Are you looking for some vegetables and herbs to plant this August? There are many different options to choose from, despite it being in the summer! In this article, gardening expert Logan Hailey walks through her favorite garden grown herbs and veggies to start planting in the heat of the summer!

winter crops

Vegetables

Winter Crops: 21 Veggies You Can Grow This Winter

Are you looking for some cold-weather crops you can add to your garden this season? There are a number of vegetables that are cold hardy and can actually be planted in the winter depending on your hardiness zone. In this article, gardening expert Logan Hailey examines her favorite winter-friendly crops for every climate!

vertical garden

Gardening Tips

4 Ways to Grow Vertical Gardens in Small Spaces

If you are struggling with a lack of space, growing a vertical garden can be a great way to solve that problem. While it can seem intimidating, it's actually not too complex if you follow the right steps. In this article, gardening expert Melissa Strauss walks through each step you'll need to take for a successful vertical garden in a tight space.