There are plenty of fast-growing flowering annuals you can sow in midsummer to enjoy flowers into fall including marigold, calendula, and zinnias. Have a look at the choices, check your days to first frost, and get your seeds ready so you don’t miss out.
There are also lots of edible crops to start now. See 20 Vegetables to Sow Midsummer for Fall for suggestions.
Sowing Seeds for Late Summer Blooms
After the flourish of spring planting, many of us take it easy in the summer garden, just tending to some weeding, harvesting some early fruit and vegetable crops, and trellising vining plants.
But there’s a huge reward ahead if you make time to sow seeds in the middle of summer—during June and July.
The seeds I’ve listed here are flowering annuals to enjoy before cool fall and winter weather sets in. I’ve also got a midsummer sowing plan for cool-tolerant vegetables here.
Getting Started
To get started, you will need to know your average first frost date and hardiness zone. I’ve provided links below to lookup this information.
This information is intended for gardeners in zones 4 to 8 (ish) simply because that’s what I’m most familiar with.
What we choose to sow is based on how many days we have before first frost. That number should be greater than the “days to maturity” or “days to bloom” listed on the flower seed packet plus a week or two if possible.
The most important step is to get your seeds asap.
You will sow directly outdoors unless it’s unusually hot or dry. If conditions are extreme, indoor seed starting or a covered patio may be better options.
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.
Ecoregion | Learn about local native plants, animal species, and environmental conditions to make garden choices that benefit your ecosystem.
Learn More: Understanding Frosts & Freezing For Gardeners
Flower Seeds to Sow Midsummer
Once you know how many days you have until first frost, browse your favorite seed sellers to see what fits your timeline.
I’ve provided a chart (below) listing average days to bloom to help refine your options. But, even within the same species there can be wide variations in timing, so, if one variety doesn’t work, another might. Sunflowers are a good example: some dwarf varieties need just a couple of months where the tall varieties with large heads need several months more.
You’ll also notice that some flowering annuals are labelled as hardy or half-hardy. This means they can tolerate some cold around frost time which is great for a longer bloom time.
And, as always, avoid any plants known to be invasive or problematic in your area.
The number of days to germinate listed are based on numbers provided by several seed companies and apply to growing in the recommended conditions including the preferred soil temperature at sowing time. So read your seed packets to give your seeds their best start and allow more time if your conditions are not optimum.
Mail Order Seeds
- SeedsNow | Botanical Interests United States
- West Coast Seeds Canada
I’ve linked to Botanical Interests seeds below. You can find more seed sellers here: United States | Canada.
Seed Suggestions
1Amaranthus
(Amaranthus spp.)
Amaranthus (Amaranthus spp.)
Full sun
Seeds
Amaranth | Botanical Interests (US shipping)
Seed Sowing Soil Temperature
65-75°F (18-24°C)
Days to Germinate
7-10
Days to Bloom After Sowing
40-105 (6-15 weeks)
2Cornflower
(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
Can also sow around last frost for next growing season.
Days to Germinate
7-14
Days to Bloom After Sowing
65-75 (9-10 weeks)
3Butterfly Flowers
(Tithonia rotundifolia)
Butterfly Flowers (Tithonia rotundifolia)
Full sun
Seeds
Butterfly Flower (Mexican Sunflower)| Botanical Interests (US Shipping)
Seed Sowing Soil Temperature
70°F (21°C)
Days to Germinate
7-14
Days to Bloom After Sowing
80 (11 weeks)
4Calendula
(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)
5California Poppy
(Eschscholzia californica)
California Poppy (Eschscholzia californica)
Sun
Seeds
California Poppy | Botanical Interests (US Shipping)
Seed Sowing Soil Temperature
55°F (12°C)
Tip
Can also sow outdoors after last frost for next growing season.
Days to Germinate
14-21
Days to Bloom After Sowing
60-75 (8-10 weeks)
Tips: Midsummer Garden Tasks: What To Do Now
6Cosmos
(Cosmos bipinnatus and
C. sulfureus)
Cosmos (Cosmos bipinnatus and C. sulfureus)
Sun
Seeds
Cosmos | Botanical Interests (US Shipping)
Seed Sowing Soil Temperature
70-75°F (21-25°C)
Days to Germinate
7-10
Days to Bloom After Sowing
70-84 (10-12 weeks)
7Flax
(Linum usitatissimum)
Flax (Linum usitatissimum)
Sun
Seeds
Flax | Botanical Interests (US Shipping)
Seed Sowing Soil Temperature
50-80°F (10-27°C)
Tip
Can also sow after last frost for next growing season.
Days to Germinate
21
Days to Bloom After Sowing
50-60 (7-8 weeks)
8Marigold
(Tagetes sp.)
Marigold (Tagetes sp.)
Sun
Seeds
Marigold | Botanical Interests (US Shipping)
Seed Sowing Soil Temperature
70-75°F (21-25°C)
Tip
Can also sow indoors in vermiculite 6-8 weeks before last frost or directly outdoors around last frost for next growing season.
Days to Germinate
4-12
Days to Bloom After Sowing
42-70 (6-10 weeks)
9Morning Glory
(Ipomoea purpurea)
Morning Glory (Ipomoea purpurea)
Sun
Seeds
Morning glory | Botanical Interests (US Shipping)
Avoid Bindweed (Convolvulus arvensis) also known as “morning glory” which is highly invasive.
Seed Sowing Soil Temperature
70-85°F (21-30°C)
Tip
Outdoor seed starting may be slower than indoor.
Days to Germinate
10
Days to Bloom After Sowing
100 (14 weeks)
10Nasturtium
(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)
11Nigella
(Nigella damascene)
Nigella (Nigella damascene)
Sun
Seeds
Nigella | Botanical Interests (US Shipping)
Seed Sowing Soil Temperature
65-70°F (18-21°C)
Days to Germinate
10-15
Days to Bloom After Sowing
65-75 (9-11 weeks)
12Poppy
(Papaver spp.)
Poppy (Papaver spp.)
Sun
Seeds
Poppy | Botanical Interests (US Shipping)
Seed Sowing Soil Temperature
Perennial 68-70°F(20-21°C)
Annual 60°F(16°C)
Days to Germinate
14-28
Days to Bloom After Sowing
55 (8 weeks)
13Phlox
(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
Can also direct sow when ground is workable in spring.
Days to Germinate
5-10
Days to Bloom After Sowing
50-65 (7-9 weeks)
14Sunflower
(Helianthus annuus)
Sunflower (Helianthus annuus)
Sun
Seeds
Sunflower | Botanical Interests (US Shipping)
Look for dwarf varieties.
Get my best tips for growing sunflowers here.
Seed Sowing Soil Temperature
70-75°F (21-25°C)
Days to Germinate
14
Days to Bloom After Sowing
75-100 (10-14 weeks) Check for your variety.
15Sweet 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)
16Sweet 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 moist paper towel for 1 day prior to sowing.
Best sweet pea growing tips
How to save sweet pea seeds
Days to Germinate
28
Days to Bloom After Sowing
50-60 (7-9 weeks)
17Zinnia
(Zinnia elegans)
Zinnia (Zinnia elegans)
Sun
Seeds
| Botanical Interests (US Shipping)
Seed Starting Soil Temperature
70-80°F (21-26°C)
Tips
Can also sow directly outdoors after last frost.
Pinch stems for more flowers.
Save zinnia seeds for next year.
Days to Germinate
5-24 days
Days to Bloom After Sowing
50-60 days (7-8 weeks)
Resources
- Midsummer Garden Tasks: What To Do Before Fall
- 20 Vegetables to Sow Midsummer for Fall (Seed Sowing Plan)
Plant Life Cycles
Annuals complete their life cycle (germination, flowering, setting seed) in one growing season and do not grow back. The term is used both for plants that have a short life cycle and do not tolerate freezing temperatures. Petunias and zinnias are common annuals.
Perennials have a multi-year life cycle and, if suited to our hardiness zone, will go dormant in the winter and resume growth in spring—year after year.
- The above-ground growth of perennial flowers like coneflowers (Echinacea spp.) typically dies off in fall with new growth appearing from the roots in spring.
- Woody perennial shrubs and vines drop leaves from their hardwood in fall and grow new leaves, shoots, and flowers in spring or summer. Examples include sand cherry (Prunus pumila) and honeysuckle (Lonicera spp.).
Biennials take two years to complete their life cycle (from germination to seed production). Biennial vegetables like carrots can be harvested in year one for food or left over winter for a second year if flowering and seed production is desired.
Time to get your seeds and start sowing.
~Melissa the Empress of Dirt ♛