17 Seeds You Should Start Now for March Transplanting

Indoor seed starting is a treat! You can turn a bare windowsill into a bustling propagation station full of seedlings. There are plenty of options, whether you like leafy greens, onions, herbs, or flowers. Most broccoli relatives prefer chilly weather, while others tolerate it until spring warmth arrives.

To start, you’ll need a few tools. You can use last year’s pots; simply wash and sterilize them before using them this season. Gather potting soil, a watering can, and trays. Trays are indispensable inside, as they catch excess water that drains from the pots. Humidity domes are beneficial but optional. They trap moisture, leading to higher germination rates.

Start cabbage seeds in January or February and plant them outside four weeks before the last average spring frost. The seedlings need a month or more to grow inside before they’re ready for transplanting. Mature cabbage is frost-tolerant and works well as a fall crop. 

Collards

	botanical name Brassica oleracea var. viridis
	sun requirements Full sun
	height 2-3’
	hardiness zones 2-11

Collards are close relatives of cabbage—they sprout long, strappy green leaves that cook well in recipes. Heat and cold-tolerant, collards are one of the toughest leafy green vegetables you can cultivate in the garden. 

Though they tolerate heat, collards prefer cool, springtime weather while they mature. Start them in pots inside, then bring them outside for hardening off and planting in March or April. After establishing themselves they reach tall and wide, with some towering varieties reaching six feet tall! Most types stay between two and three feet, about the same height as broccoli. 

Kale

	botanical name Brassica oleracea var. sabellica
	sun requirements Full sun
	height 12-20”
	hardiness zones 2-11

Kale is also a relative of broccoli, cabbage, and collards! It’s a cold-hardy biennial that grows leaves in its first year and flowers in the second. I start indoor seedlings every February for transplanting in March in zone 8. Growers in colder zones may do the same, though the seedlings need a hardening-off period before transplanting.

Hardening off involves placing kale outdoors for a week or two in a protected location. After adapting to outdoor weather, the plants are ready for planting in the garden. Kale, like cabbage, works well as a fall or spring crop. 

Kohlrabi

	botanical name Brassica oleracea var. gongylodes
	sun requirements Full sun
	height 10-12”
	hardiness zones 2-11

A relatively new garden introduction, kohlrabi sprouts large, crunchy stems full of vitamins, fiber, and minerals. They taste like a mix between broccoli and cabbage; the flavor is sweet, nutty, and peppery. Kohlrabi looks like common root crops, though the bulbous edible portion is an enlarged stem. 

This unusual vegetable grows best when the weather is cool, mild, and sunny. Start seeds six weeks before you plan on planting the seedlings outdoors. You may move them outside four weeks or less before your last average frost-free date. 

Mustard

	botanical name Brassica juncea
	sun requirements Full sun to partial shade
	height 1-2’
	hardiness zones 2-11

Mustard isn’t just the source of the delicious yellow condiment of the same name, it’s also an edible leafy green vegetable! Mustard leaves are nutritious, delicious, and easy to grow. More cold tolerant than most other crops, it’s perfect for northern gardens with late spring frosts.

Growers in zones 7 and 8 should start mustard seeds in February for setting out in March. If you live in zones 2 through 6, do so a month or two later. Start seeds in March and harden off the seedlings in April. 

Lettuce

	botanical name Lactuca sativa
	sun requirements Full sun to partial shade
	height 6-12”
	hardiness zones 2-11

Lettuce excels during cool weather, growing lush red, green, or striped leaves. The foliage is delicious in salads, smoothies, and sandwiches. Hundreds of varieties offer the ultimate selection; choose butterhead, crisphead, leaf lettuce, or summer crisp types.

Though you may start lettuce seeds indoors, the plants often grow better when you direct sow them outdoors. I like to do both; I grow starts inside as a backup for outdoor lettuce, in case the seeds fail to sprout. Try both methods, then see which works best for you and your garden.

Endive

	botanical name Cichorium endivia
	sun requirements Full sun
	height 1-2’
	hardiness zones 4-9

Endive is uncommon in American gardens, though it shouldn’t be! It’s a gorgeous leafy green vegetable with a slightly bitter taste. The leaves work well in salad mixes with arugula, lettuce, and radicchio. Funky varieties like ‘Olesh Tres Fine’ offer white inner leaves and green outer ones for a stunning ornamental effect. 

Endive tolerates harsh winter weather, growing well despite recurring frosts. Plant transplants outdoors four to six weeks before your last frost date. Like lettuce, endive will bolt as temperatures rise and days lengthen in spring. Grow it during fall or spring to keep it compact and flavorful. 

Onion

	botanical name Allium cepa
	sun requirements Full sun
	height 1-2’
	hardiness zones 2-9

Onion plants need lots of time to grow swollen bulbs. They first grow leaves that capture sunlight, allowing them to photosynthesize and gather energy. They push the sugars and nutrients into their lower stems, creating enlarged, bulbous portions we eat and enjoy. Though the swollen stem is the part we eat most often, the leaves and flowers are edible too!

Which onion to grow depends on your climate. There are three types of onions: long-day, intermediate-day, and short-day. Short-day onions like warm climates, long-day types perform in cold climates, and intermediate-day varieties grow in the regions in between.

Parsley

	botanical name Petroselinum crispum
	sun requirements Full sun
	height 1-3’
	hardiness zones 2-11

Parsley is one tough biennial! It grows herbal, aromatic leaves from an enlarged root system underground. Though frost kills most annual and biennial herbs in my garden, parsley always survives the winter! If mature plants die during ice storms, they leave seeds that sprout the next spring and fall. 

Though frost-tolerant when mature, young parsley seedlings are tender. They’ll quickly wither as bone-chilling temperatures persist in late spring. Plant parsley seedlings two to three weeks before your last spring frost date to avoid cold damage. 

Spinach

	botanical name Spinacia oleracea
	sun requirements Full sun to partial shade
	height 6-12”
	hardiness zones 2-11

Frost tolerant, deliciously sweet, and tender, spinach is one of the easiest and healthiest crops for the home garden. Sow a large patch for fresh leaves all season long, or plant them sporadically among other cold-loving species. They grow low to the ground while the weather is cool before bolting in late spring and summer. 

Bolting tends to ruin the flavor of the leaves, so it’s best to grow spinach while the weather is mild and cool. Spinach, like lettuce, is sensitive to root disturbance. If you’re starting them in pots, take care while transplanting to avoid damaging the soft roots. 

Pea

	botanical name Pisum sativum
	sun requirements Full sun to partial shade
	height 1-3’
	hardiness zones 2-11

Peas climb as they grow, latching onto whatever they can to hoist themselves upward. The vines are like bean vines, with thin tendrils that wrap around tall stakes. Though peas stay between one and three feet without support, they can grow much taller on stakes, stalks, or sticks. 

Like lettuce and spinach, peas are sensitive to root disturbance. Grow them in pots that you can transplant directly into the garden, or take care while you move them to avoid damaging the roots. The best pots are biodegradable ones that decompose and let the pea roots creep out over time. 

Broccoli

	botanical name Brassica oleracea var. italica
	sun requirements Full sun
	height 1-3’
	hardiness zones 2-11

Crunchy green broccoli heads taste best when they grow in the home garden! They’re one of the easiest vegetables to cultivate, as they excel from late winter through spring. Broccoli plants are a bit less frost tolerant than collards and cabbage, and it’s best to move them outside in late March or early April to avoid frost damage.

Start broccoli seeds in late February or early March. They’ll grow for a month indoors, and they’re ready for the outdoor garden two weeks before your last frost-free date. If it performs poorly in your yard, try growing it as a fall crop instead.

Cauliflower

	botanical name Brassica oleracea var. botrytis
	sun requirements Full sun
	height 1-3’
	hardiness zones 2-11

Cauliflower, like broccoli, prefers mild weather to mature in. It does poorly in hot, dry soils that are common during summertime. Though cauliflower needs more care than broccoli, its scrumptious heads are a treat when you grow them yourself.

For optimal cauliflower growth, start plants indoors a month or more before your last frost; then, transplant grown seedlings outside two weeks before the final frost. The goal is to have the plants form heads well before the heat of summer arrives.

Leek

	botanical name Allium porrum
	sun requirements Full sun
	height 1-3’
	hardiness zones 5-9

Leeks are onion and garlic relatives with sweet, mild stalks that form thick stems. Both their white lower portions and upper green ones are edible. Sauté them in stir-fries, or bake them alongside carrots, beets, and potatoes. Potato leek soup is a classic recipe—it gives you a good reason to cultivate homegrown leeks.

Though you may start leek seeds now, they need two months of indoor growing before they’re ready for transplanting. Start them in January or early February for planting in late March. The seedlings perform well if you move them into the garden two weeks before your final frost. 

Dianthus

	botanical name Dianthus spp.
	sun requirements Full sun to partial shade
	height 4”-3’
	hardiness zones 4-9

Cottage gardens invoke a peaceful feeling that’s soothing for the soul. The plants in them are often cheery, bright, and colorful. Dianthus is a perfect cottage garden plant, producing clusters of pink, red, white, or purple flowers atop slender stems. It grows grass-like foliage on the ground, where it gathers energy to produce blooms. 

Dianthus also goes by the name Sweet William. The plants are often biennial, growing leaves the first year and flowers the second, though some species are perennial. Start them in pots two months before the last frost, and set them out two weeks before the date. 

Lupine

	botanical name Lupinus spp.
	sun requirements Full sun to partial shade
	height 1-4’
	hardiness zones 4-8

Lupine is another flowering species that stands out in ornamental gardens. Many species are native to North America, growing from the West Coast to the East Coast. They send up long, flowering stalks with rows of blooms. Bumblebees love them, and you’ll often find them swarming the blossoms.

February is ideal for starting lupines. Cold stratify them first. Then, plant them in pots and move sprouted seedlings to the garden one to two weeks before the final frost. Many lupines are biennial; reseed them every year for a constant supply of bodacious blooms!

Phlox

	botanical name Phlox spp.
	sun requirements Full sun to partial shade
	height 3”-5’
	hardiness zones 3-9

Phlox are incredibly diverse—some species are sprawling ground covers, while others are tall-reaching perennials. Which phlox is best for you depends on what you’re looking for. Creeping phlox is superb in rock and cottage gardens, covering bare ground with ease. Perennial, tall types work well in borders, tree wells, and between shrubs.