7 best flowers to sow in March for amazing spring colors

Cosmos flowers in a field
(Image credit: Shutterstock)

March is a turning point in the gardening calendar. After months of muted winter tones, the promise of bold, colorful blooms is often exactly what outdoor spaces — and gardeners — need.

Bright flowers don’t just enhance curb appeal; they can boost mood, support pollinators emerging from their winter dormancy, and bring fresh energy to beds, borders, and containers. But to achieve a colorful array of blooms, you’ll want to get a head start now.

Most spring bloomers thrive in full sun, well-drained soil enriched with compost, and steady moisture during germination. Get those basics right, and you’ll be rewarded with a vibrant display that carries you through to summer. By planting now, you ensure months of enjoyment from the garden — not just peak June and July.

Here are 7 flowers to sow now, to create a spring garden that’s alive with color, texture, and the welcome return of pollinators. It's time to get your best gardening gloves on and get sowing.

7 flowers to sow in March

1. Cosmos

Pink cosmos flower

(Image credit: Shutterstock)

Cosmos are wonderfully unfussy flowers that deliver airy foliage and daisy-like blooms in shades of pink, white, and crimson. In warmer zones, you can scatter seeds directly into prepared beds in March and lightly rake them in, and they prefer not to be buried too deeply into the soil. In cooler regions, start them indoors and transplant to their outdoor home after the danger of frost passes.

Cosmos actually perform best in average to slightly poor soil and full sun, producing more flowers when they’re not overfed, so don’t apply fertilizer.

Growing zones: 2–11

2. Calendula

Closeup of the short lived orange and yellow flowers of Calendula

(Image credit: Shutterstock)

If you’re eager for color as early as possible, calendula, also known as pot marigold, is a reliable choice. Its sunny orange and yellow blooms thrive in cool conditions, making March an ideal month for direct sowing in many parts of the country. Simply press seeds about a quarter-inch into well-drained soil and keep the area evenly moist until seedlings appear.

Calendula tolerates light frost and will continue flowering steadily if you remove spent blooms, so you’re sure to get months of enjoyment as long as you keep the plant well-maintained. It’s equally at home in garden beds or brightening up spring containers, so check how workable your soil is and go from there.

Growing zones: 2–11

3. Sweet Peas

Bouquet of cream, purple and lilac sweet peas with other flowers

(Image credit: Shutterstock)

For fragrance as well as beauty, the sweet pea is hard to beat. These climbers prefer cool roots and crisp air, so early spring sowing gives them a strong start before summer heat arrives. In zones 3–7, sow seeds outdoors as soon as the ground can be worked; in colder climates, begin indoors and transplant carefully.

If you’re sowing a little behind schedule, soaking seeds overnight can also speed up germination. Plant the seeds in rich, well-drained soil and install a trellis right after you plant. The sweet peas will quickly scramble upward in search of support, so it’s important to have that structure ready.

Growing zones: 3–10

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4. Pansies

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(Image credit: Shutterstock)

The pansy is practically synonymous with early spring, often cropping up in natural parks and woodland areas. Their velvety petals and bold ‘faces’ hold up well in chilly weather, even tolerating a light frost, which makes them perfect for early spring planting.

In milder regions, March is perfect for planting them directly into borders or containers; in colder zones, start seeds indoors or set out nursery-grown plants once the soil is workable. They prefer evenly moist, compost-enriched soil and can handle full sun to partial shade, making them a flexible option for brightening tricky spots and adding color to dim areas.

Growing zones: 4–10

5. Nasturtiums

Red, orange and yellow nasturtiums in flower

(Image credit: Shutterstock)

Few flowers are as easy going as nasturtiums, which is why they are often recommended for beginner gardeners. However, experienced green thumbs can also benefit from adding this plant to their garden. The nasturtium’s vibrant red, orange, and golden blooms spill beautifully from raised beds and hanging baskets, making it an ideal option for smaller spaces with only room vertically.

In warmer zones, sow seeds straight into the ground in March, planting them about an inch deep. In cooler areas, wait until the soil warms slightly or start in biodegradable pots to protect delicate roots. Interestingly, nasturtiums prefer lean soil, so skip the fertilizer, or you’ll get lots of leaves but fewer flowers.

Growing zones: 3–11

6. Snapdragons

Orange and yellow snapdragon flowers

(Image credit: Shutterstock)

Looking to add height and drama? Snapdragon produces tall spikes packed with colorful blooms that stand out in mixed borders. They’re a great way to add visual interest without requiring much maintenance. In zones 7–10, seeds can be planted outdoors in March; elsewhere, start indoors about six weeks before your last frost. Press seeds gently onto the soil surface since they need light to germinate.

With fertile, well-drained soil and consistent watering, snapdragons will reward you with weeks of vertical color, which also makes them excellent as cut flowers too.

Growing zones: 7–10 (grown as annuals in most zones)

7. Sunflowers

Sunflowers

(Image credit: Shutterstock)

Bold and beloved, sunflowers bring instant cheer to any garden. There’s a reason why so many schoolchildren get their first gardening experience by trying to grow the tallest sunflowers. This plant is a cheerful addition to nearly any yard.

While often sown later in spring, you can start seeds indoors in March in cooler zones to get a head start, or direct sow in mild climates once the soil can be worked. Plant seeds about an inch deep in a sunny, sheltered location with good drainage.

If you’re not sure that you have the room for the traditional, towering sunflower, then look into some of the other varieties available — dwarf types are well-suited to containers, for instance. If you do go for the taller species, they work well at the back of borders — just be prepared to stake taller plants if winds are strong.

Growing zones: 2–11


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Madeleine Streets
Contributing Gardens Writer

Despite making her home in urban metropolises, Madeleine Streets has been nurturing a green thumb for decades.

Raised by a garden designer, she is putting that childhood education to use by helping others learn how to make their garden bloom, while filling her own New York home with cat-friendly plants.

When not writing about gardening and the outdoors, Madeleine loves to cook, study wine and borrow books from her local library.

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