10 Spectacular Fast-Growing Flowers

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.

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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 along, 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 by species and how deep the roots grow, in general, a pot 10-inches wide by 8 to 10-inches deep (or more) 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.

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Contents

• 10 Fast-Growing Flowers
  • Calendula
  • Zinnia
  • Flax
  • Sweet Pea
  • Phlox
  • Nasturtium
  • Marigold
  • California Poppy
  • Sweet Alyssum
  • Cornflower
• Resources

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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 (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 (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

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

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)

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5Phlox

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

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)

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7Marigold

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)

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8California Poppy

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

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)

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10Cornflower

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

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 ♛