These fast-growing annual flowers can be started from seed with the quickest ones like calendula blooming in just six weeks. Beautiful, easy to grow, and reliable, they are favorites for many gardeners.
Growing food? This lists quick-growing vegetables perfect for spring and fall.
Fast Flowers From Seed
We want flowers and we want them now! So what are the fastest growing flowers?
If you are growing from seed and want blooms as soon as possible, you’ll want the annuals listed below. Annuals are plants that fruit and flower in their first year, and for those of us in cold climates, they are short-lived, lasting just one growing season. But what a season it is.
Realistically, nothing flowers in just a week or even a month, but plants like calendula, sweet pea, and zinnia can flower in just 6 to 8 weeks after sowing. And, as far as nature goes, that’s fast.
The selections here are all reliable, easy to grow, and provide a nice, long bloom time—that’s one of the perks of growing annuals. They go all-in for the season, holding nothing back.
The key to success, as always, is to provide the right conditions for each plant, from the seed starting stage onward, to ensure they can deliver everything as promised.
To help speed things, if indoor seed starting is recommended on the packet, go for it. Some plants like annual phlox, flax, and zinnia may do best with direct sowing after last frost—meaning it’s best to sow the seeds directly outdoors in their final location—but others like nasturtium and marigold can get a jump start indoors.
Besides sowing at the right time, providing the right soil temperature during germination can save you days or weeks waiting for seeds to sprout. Every species has a sweet spot where, within a certain temperature range, germination is quick and optimal. To measure, a simple kitchen thermometer like this works fine. I’ve listed the optimum soil temperatures below.
Attract Pollinators
One of my favorite uses for flowers like these is to attract pollinators and other beneficial insects. Planted amongst the vegetables, you get bursts of color and more bees, butterflies, flies, and everything else that brings a garden life. There is also the potential to protect or benefit crops with specific inter-plantings.
Can I grow fast-growing flowers in containers?
Yes. Annuals are ideal for growing in pots. While the recommended container size will vary depending by species and how deep the roots grow, in general, a pot 10-inches wide by 8 to 10-inches deep should be suitable. With organic potting mix and adequate watering, don’t worry about the seed spacing rules on the packet. You can pack a lot of annuals into one pot.
Contents
10 Fast-Growing Flowers
I’ve listed these plants in order starting with the fastest from seed to bloom. Within each species you may find varieties that are faster or slower so be sure to check the information in the seed catalog or on your seed packet to be sure.
1Calendula
(Calendula officinalis)
Calendula (Calendula officinalis)
Sun or Part Sun, Cold-Tolerant
Seeds
Calendula | Botanical Interests (US Shipping)
Seed Sowing Soil Temperature
70°F (21°C)
Tips
Pinch back to encourage bushier growth.
Look for tall varieties (not dwarf) if you want cut flowers.
Days to Germinate
7-21
Days to Bloom After Sowing
45-56 (6-8 weeks)
2Zinnia
(Zinnia elegans)
Zinnia (Zinnia elegans)
Sun
Seeds
Zinnia | Botanical Interests (US Shipping)
Seed Starting Soil Temperature
70-80°F (21-26°C)
Tips
Sow directly outdoors after last frost.
Pinch stems for more flowers.
Save seeds for next year.
Days to Germinate
5-24 days
Days to Bloom After Sowing
50-60 days (7-8 weeks)
3Flax
(Linum usitatissimum)
Flax (Linum usitatissimum)
Sun
Seeds
Flax | Botanical Interests (US Shipping)
Seed Sowing Soil Temperature
50-80°F (10-27°C)
Tip
Direct sow after last frost.
Days to Germinate
21
Days to Bloom After Sowing
50-60 (7-8 weeks)
4Sweet Pea
(Lathyrus odoratus)
Sweet Pea (Lathyrus odoratus)
Sun
Seeds
Sweet Pea | Botanical Interests (US Shipping)
Be sure they are annuals. The perennial (L. latifolius) is invasive.
Seed Sowing Soil Temperature
55-65°F (12-18°C)
Tips
Soak seeds in damp paper towel for 1 day prior to sowing.
Best sweet pea growing tips.
How to save seeds.
Days to Germinate
28
Days to Bloom After Sowing
50-60 (7-9 weeks)
5Phlox
(Phlox drummondii)
Phlox (Phlox drummondii)
Sun, Cold-Tolerant
Seeds
Phlox | Botanical Interests (US Shipping)
Seed Sowing Soil Temperature
60°-65°F (16°-18°C)
Tip
Direct sow when ground is workable in spring.
Days to Germinate
5-10
Days to Bloom After Sowing
50-65 (7-9 weeks)
6Nasturtium
(Tropaeolum majus)
Nasturtium (Tropaeolum majus)
Sun, Cold-Tolerant
Seeds
Nasturtium | Botanical Interests (US Shipping)
Seed Sowing Soil Temperature
55-65°F (12-18°C)
Tip
Sow indoors or directly outdoors.
Part-shade makes a leafier, sprawling plant.
Days to Germinate
7-10
Days to Bloom After Sowing
60 (8 weeks)
7Marigold
(Tagetes sp.)
Marigold (Tagetes sp.)
Sun
Seeds
Marigold | Botanical Interests (US Shipping)
Seed Sowing Soil Temperature
70-75°F (21-25°C)
Tip
Sow indoors in vermiculite 6-8 weeks before last frost or directly outdoors around last frost.
Days to Germinate
4-12
Days to Bloom After Sowing
42-70 (6-10 weeks)
8California Poppy
(Eschscholzia californica)
California Poppy (Eschscholzia californica)
Sun
Seeds
California Poppy | Botanical Interests (US Shipping)
Seed Sowing Soil Temperature
55°F (12°C)
Tip
Sow directly outdoors after last frost.
Days to Germinate
14-21
Days to Bloom After Sowing
60-75 (8-10 weeks)
9Sweet Alyssum
(Lobularia maritima)
Sweet Alyssum (Lobularia maritima)
Sun or Part Sun, Cold-tolerant
Seeds
Sweet Alyssum | Botanical Interests (US Shipping)
Look for dwarf varieties.
Seed Sowing Soil Temperature
55-70°F (13-21°C)
Tip
Seeds require light to germinate: sow on soil surface.
Dwarf varieties spread as ground cover and reseed.
Days to Germinate
8-10
Days to Bloom After Sowing
50-60 (7-8 weeks)
10Cornflower
(Centaurea cyanus)
Bachelor’s Button / Cornflower (Centaurea cyanus)
Full sun
Seeds
Cornflower | Botanical Interests (US Shipping)
Seed Sowing Soil Temperature
60-70°F (15-21°C)
Tip
Direct sow around last frost.
Days to Germinate
7-14
Days to Bloom After Sowing
65-75 (9-10 weeks)
Resources
Lookup Your Numbers
Find Your Frost Dates & Hardiness Zone
- Plant Hardiness Zones |
United States | 
Canada
These are listed on seed packets and plant tags to guide your choices.
- Average Frost Dates | Use this calculator at Almanac.com. Enter your city and state or province to find your first and last frost dates and number of frost-free days.
For more plant ideas like this, also see flower seeds to sow mid-summer. Lots of these fast-growers are on the list.
~Melissa the Empress of Dirt ♛
