Days from Seed to Bloom For 15 Popular Garden Flowers: Planting Guide

For weeks now, I’ve been looking longingly at my stack of seed packets and watching the weather forecast. Only a few more weeks before I can start crossing off dates on my calendar, counting down the days until my flowers bloom. It’s the only thing more exciting than seeing those first little sprouts popping up through the dirt. 

Some plants take a long time to flower, while others seem to pop right up and get started in a hurry. I like to plant a variety of flowers with different bloom times so that my beds are always cheery and colorful. If you also like to do this, it’s good to know how long it takes different plants to grow from seed to bloom time. 

Perhaps my favorite thing about zinnias is that they go from seed to bloom in right around two months. Directly sow these seeds, as they don’t like to have their roots disturbed. They like loose soil that drains well and don’t mind poor or sandy soil types. Taller varieties may benefit from support or staking. 

Cosmos ‘Rubenza’

	botanical name Cosmos bipinnatus ‘Rubenza’
	sun requirements Full sun
	height 24”-32”
	hardiness zones 2-11

Another plant I grow every year—cosmos—is delightfully tough, even though it has a light and airy texture. Its fern-like foliage and masses of blooms make it great for the cutting garden, though its individual vase life is not excellent. 

Depending on the weather, it can take two to three months from the time you sow seeds until they bloom. You can direct sow or transplant these, both seem to work fine. Direct sowing may result in more vigorous plants, however, 

Sunflowers ‘Mammoth’

	botanical name Helianthus annuus ‘Mammoth’
	sun requirements Full sun
	height Up to 12’+
	hardiness zones 2-11

Sunflowers don’t have a one-size-fits-all answer to the question of flowering time. Because of the incredibly wide range of sizes, some take as few as 70 days, while larger types can take as many as four months. ‘Mammoth’ is a 12′ cultivar,  so it falls toward the longer end of that range. 

Direct sowing is possible but not ideal. Snapdragons are slow growers, and the seeds are tiny. They also need light to germinate, which creates a real conundrum. You’ve got to keep those seeds in place, on top of the soil, until they germinate for up to two weeks. It’s best to start them indoors well ahead of your last frost date. 

Purple Coneflowers

	botanical name Echinacea purpurea
	sun requirements Full sun to partial shade
	height 3’-4’
	hardiness zones 3-8

Coneflowers are tricky because they don’t always flower in their first year. However, if you start the seeds early enough, you might see blooms around mid-summer. Otherwise, they will spend their first year focusing on root and basal leaf growth. 

You can start these outdoors about a month before your last frost date. If you want those first-year flowers, aim to get them growing indoors at least two months ahead of time. Simulate cold stratification for seeds sown indoors. They are perennial in zones 3-8 and sometimes 9. Outside of those zones, start them early and transplant them. 

Common Milkweed

	botanical name Asclepias syriaca
	sun requirements Full sun
	height 24”-36”
	hardiness zones 3-10

If you want monarch butterflies in your pollinator patch, milkweed is a must-have. Even though it doesn’t always bloom in the first year, it will still attract those magnificent butterflies. Milkweed is the sole larval food for the monarch, any kind will do, but it’s a good idea to find one that is native to your region. 

If you plant these directly in the garden in the fall, they will germinate early, and you’ll have first-year flowers. Planted in the spring, they may not. Start in the spring, indoors, about two months ahead of your last frost date. Cold stratify for three to six weeks in the refrigerator ahead of sowing.

Bachelor’s Buttons ‘Blue Boy’

	botanical name Centaurea cyanus ‘Blue Boy’
	sun requirements Full sun
	height 24”-36”
	hardiness zones 2-11

Bachelor’s buttons are pretty little things. They are drought tolerant and can handle a light freeze, so they’re flexible about planting time. You can sow them in the fall for spring flowers or start them a few weeks before your last frost date. 

Direct sowing is the preferred method of bachelor’s buttons. They don’t like root disturbance. If you plant in the fall, start counting from germination time in spring. From seed to flower is about 65 days. These are some of the earlier blooming annuals in springtime. ‘Blue Boy’ is a classic, cornflower blue variety that bees adore. 

Lavender ‘Munstead’

	botanical name Lavandula angustifolia ‘Munstead’
	sun requirements Full sun
	height 12”-18”
	hardiness zones 5-9

Lavender is wonderful in so many ways. For one thing, it’s incredibly low-maintenance. It needs little water and no fertilizer and doesn’t mind poor and sandy soil—in fact, it rather prefers it! The main requirement for blooming is full exposure, which means it needs a lot of light. 

If you want your lavender to bloom in its first year, sow the seeds in late fall. If you wait and plant in spring, you may not see flowers until the second summer. Not to worry, the foliage is lovely and aromatic, just like the blossoms. 

Black-Eyed Susans ‘Indian Summer’

	botanical name Rudbeckia hirta ‘Indian Summer’
	sun requirements Full sun
	height 36”-42”
	hardiness zones 4-9

Black-eyed Susans are among the best plants for attracting and feeding native bees. I love to stand outside and watch the amazing variety of pollinators that visit them. While they are perennial in some zones, they aren’t all that reliable, so most gardeners treat them as annuals. They re-seed, so once you have them, there’s a strong chance they will return if you leave the seed heads on them.

You can directly surface sow these in the fall or a couple of weeks before your last frost date. They don’t mind transplanting, so starting them indoors is effective and recommended. If you start them indoors, cold stratify them in your refrigerator for a few weeks first. Start them 8-10 weeks ahead of that last frost. 

French Marigolds ‘Lemon Drop’

	botanical name Tagetes patula ‘Lemon Drop’
	sun requirements Full sun
	height 6”-12”
	hardiness zones 2-11

Charming French marigolds make wonderful companions in vegetable and herb gardens. They repel insects and have bright, cheerful flowers that are edible and make attractive garnish. French marigolds are fast growers and will bloom in just under two months from seeds. 

You can start these indoors in late summer for fall blooms or two months before your last frost date for spring flowers. Here in zone 9, I grow them all winter, as they are incredibly frost tolerant. They will survive and continue to flower even in the low 20s (around -7°C)!

Petunias Shock Wave^® ‘Purple Tie Dye’

	botanical name Petunia x atkinsiana Shock Wave® ‘Purple Tie Dye’
	sun requirements Full sun
	height 7”-10”
	hardiness zones 2-11

Sweet-smelling petunias make a great filler and hanging plant. Their blossoms are not long-lasting, but they tend to produce quite a lot of them and have a long season. They are perennial in warm climates. Avoid direct sowing these seeds; they are small and need light to germinate. 

Surface sow these in moist potting material as far as three months ahead of your last anticipated frost date. Wait until after that date to transplant. They are not frost tolerant. You should see flowers in just over two months from these. Shock Wave^® ‘Purple Tie Dye’ is a favorite variety. I love the splashy white and purple shades. 

Sweet Peas ‘Beaujolais’

	botanical name Lathyrus odoratus ‘Beaujolais’
	sun requirements Full sun to partial shade
	height 7’-8’
	hardiness zones 2-11

Sweet peas are wonderful for growing in cool weather. Their climbing vines are delicate and beautiful, and their fragrant blossoms are simply delightful. They have long stems and are lovely in floral arrangements. 

Directly sow these sturdy seeds. They don’t transplant well. In warm climates, plant in the fall for early spring flowers. In cooler climates, go ahead and drop these in the garden about a month to six weeks ahead of your last anticipated frost date. They are highly frost tolerant. 

Dianthus

	botanical name Dianthus barbatus
	sun requirements Full sun to partial shade
	height 12”-20”
	hardiness zones 3-9

Dianthus is another plant that typically flowers in its second year. The clove-scented blossoms have an excellent vase life and are great in the cutting garden. You can sow these indoors or out. If you want to have a chance at seeing flowers in the first year, start them indoors eight to ten weeks ahead of the last frost. 

These need soil warmed to about 70°F (21°C) in order to germinate. Even in the first year, dianthus has attractive foliage. Re-seed yearly for a constant supply of flowers. 

Larkspurs ‘Shades of Blue’

	botanical name Consolida regalis ‘Shades of Blue’
	sun requirements Full sun
	height 3’-4’
	hardiness zones 2-11

Larkspurs are lovely and wonderful for the cutting garden. They also make a nice, tall backdrop for other flowering annuals. Be careful about these. All parts of the plant are toxic. They flower best in the cool weather of late spring and early summer.