Seed Sowing Calendar
Coastal Connecticut
Zone 7a Β· Last frost ~ Apr 15β20
What to plant this weekend
β
March
March 29β30
~3 weeks to last frostPrime cold-sowing window. Poppies, larkspur, and sweet peas actively want cold soil β this is exactly when they want to go in.
April
April 5β6
~2 weeks to last frostSnapdragons, scabiosa, and statice join the roster. Everything from last week still very much in play.
April 12β13
~1 week to last frostLast realistic window for sweet peas and larkspur β both bolt once heat arrives. Push past this date and you lose them for the season.
April 19β20
Around last frostCheck the forecast before committing warm-season seeds. Nasturtiums are especially frost-sensitive β one cold night sets them back significantly.
April 26β27
Post-frost, soil warmingGreen light for warm-season annuals. Zinnias want soil at 65Β°F+ β if it's been a cold April, give it one more week.
May
May 3β4
Celosia, gomphrena, and tithonia come into their own. Staggering zinnias and cosmos every 2β3 weeks extends bloom time meaningfully.
May 10β11
Portulaca and moonflower need genuinely warm soil. If spring has been cool, wait until the third week of May.
May 17β18
May 24β25
Focus on fast-maturing varieties (50β60 days). Flowers sown now will bloom well into fall.
May 31βJune 1
June
June 7β8
Stick to varieties with 55β65 day bloom times. Benary's Giant and ProCut zinnias both hit this window reliably.
June 14β15
June 21β22
Zinnias sown now will bloom in September. Quick marigolds still possible for containers.
June 28β29
Season winds down for direct-sow annuals. Nothing else to sow until October's fall sowing window opens.
July Β· August Β· September
No flower sowing during the hot season β heat prevents germination of nearly everything. Fall sowing opens in early October: poppies, larkspur, nigella, sweet peas, bachelor's buttons, and calendula go directly in the ground to cold-stratify over winter and bloom weeks ahead of anything sown in spring.
October
Seeds sown now are not meant to germinate until spring. They sit dormant through winter, cold-stratify naturally in the ground, and emerge weeks ahead of anything you'd sow in March β often with stronger root systems and earlier, more abundant bloom.
October 3β4
Ground still warm β idealWidest selection of the fall sowing season. Asclepias is notoriously slow from seed and prefers fall sowing over spring.
October 10β11
Cooling β still idealCool temps are helpful β seeds won't try to germinate before winter. Don't worry if a light frost comes; seeds in the ground are protected.
October 17β18
First frosts likelyOctober 24β25
Getting late β prioritizePoppies and larkspur are the highest-value fall sows β prioritize these if time or space is limited.
October 31βNovember 1
Last comfortable windowGround should still be workable in most coastal CT years. Seeds going in now will be well-stratified by spring.
November
November 7β8
Ground may be hard in spotsCheck that the ground is still soft enough to press seeds in. Poppies especially tolerate very late sowing.
November 14β15
Very last callPoppies only, in sheltered spots where the ground is still workable. Surface sow and do not cover β poppies need light to germinate. This is the edge of the window.
March
March 29β30
~3 weeks to last frostSoil is cold but workable. Peas thrive in cool conditions and struggle once summer heat arrives β this is exactly their window.
April
April 5β6
~2 weeks to last frostApril 12β13
~1 week to last frostApril 19β20
Around last frostWatch the forecast. Beans will sulk or rot in cold, wet soil β only sow if nights are consistently above 45Β°F.
April 26β27
Post-frost, soil warmingGreen light for warm-season crops. Succession-sow lettuce and radishes every 2 weeks for continuous harvest.
May
May 3β4
May 10β11
Start winter squash and pumpkins now β they need 90β100 days and appreciate going in by mid-May.
May 17β18
May 24β25
May 31βJune 1
June
June 7β8
June 14β15
June 21β22
Shift begins toward fall crops. Kale sown now matures in September and sweetens noticeably after the first hard frost.
June 28β29
July
July is the key window for fall brassicas β an underused and highly productive season most gardeners skip entirely.
July 4β5
July 1β15 is the ideal window for fall brassicas in Zone 7a. Sow now for September harvest.
July 11β12
July 18β19
July 25β26
Beets and carrots sown now will be ready to harvest in October.
August
The August restart for cool-season crops is one of the most satisfying moves in the garden. These plants mature into falling temperatures rather than rising heat β often the best conditions of the year.
August 1β2
August 8β9
August 15β16
Prime window for fall cool-season crops. Everything sown now matures into October's ideal conditions.
August 22β23
Lettuce getting a bit late β arugula and spinach are more reliable at this point.
August 29β30
Focus on quick-maturing greens β arugula in 30 days, radishes in 25.
September
September 5β6
First frost approachingSeptember 12β13
~5 weeks to first frostRadishes in 25 days, arugula in 30 β both feasible before mid-October frost.
September 19β20
~4 weeks to first frostMache can go in now and overwinter, ready to harvest early spring.
September 26β27
~3 weeks to first frostMache is nearly frost-proof and can overwinter. Garlic goes in anytime in October β plant it now or next month.
October
Vegetable season is largely over, but October is prime time for garlic. Plant cloves now for harvest next July.
October 3β4
October 10β11
October 17β18
Plant garlic before the ground freezes β ideally by Halloween in coastal CT.
October 24β25
Hardiness Zone
7a
Coastal Westport/Norwalk may be warmer (7b)
Last Spring Frost
~Apr 15β20
Coastal proximity can shift this earlier by a week
First Fall Frost
~Oct 15β20
Some years extend into early November along the Sound
Growing Season
~180 days
Mid-April through mid-October
Is this calendar right for your location?
This calendar is calibrated for Westport and coastal Fairfield County β not all of USDA Zone 7a. That zone covers a wide swath of the country: coastal Connecticut shares it with central Virginia, western North Carolina, Memphis, and pockets of the Pacific Northwest. Frost dates vary by weeks across that range. If you're in coastal southern Connecticut, the North Shore of Long Island, or lower Westchester County, this calendar should translate well.
About the native plant callouts
Seeds marked with ● are native to eastern North America. The list for direct-sow annuals is short β Rudbeckia hirta (black-eyed Susan), Asclepias tuberosa (butterfly weed), and cultivated sunflowers. For a richer native planting, perennials like wild bergamot, coneflower, asters, and goldenrod are the real workhorses β but those are a different guide.
About the deer-resistant filter
Deer resistance is never absolute β a hungry deer in a hard winter will eat almost anything. The filter uses "generally avoided by deer" as the standard. In a high-pressure deer area, poppies, larkspur, marigolds, and cleome are the most reliably left alone. Sunflowers, nasturtiums, cosmos, and sweet peas are reliably eaten.
Minimum soil temperatures for direct sowing
| Soil temp | What to sow |
|---|---|
| 35β45Β°F | Peas, spinach, mache, arugula, lettuce, kale, larkspur, poppies, sweet peas |
| 45β55Β°F | Beets, carrots, radishes, Swiss chard, bachelor's buttons, calendula, nigella, alyssum |
| 60β65Β°F | Beans, summer squash, cucumbers, corn, cosmos, sunflowers, marigolds, zinnias, nasturtiums |
| 70Β°F+ | Basil, okra, portulaca, moonflower, celosia, gomphrena |
