When to Start Seeds Indoors? Seed Starting Schedule

Seed Starting Schedule

Calculate when to start each crop by counting backward from your last frost date. Here's a quick reference for common vegetables:

Vegetable	Weeks Before Last Frost	Notes
Peppers	8-10 weeks	Slow germination, need warmth
Eggplant	8-10 weeks	Similar to peppers
Tomatoes	6-8 weeks	Fast growers once started
Broccoli/Cabbage	6-8 weeks	Cool-season crops
Herbs (basil)	4-6 weeks	Wait until warm to transplant
Lettuce/Greens	4-6 weeks	Can also direct sow
Squash/Cucumber	3-4 weeks	Don't start too early

Sample Last Frost Dates by City

Here are approximate last frost dates for major US cities. Your specific location may vary - always check local sources.

Northern Cities

Minneapolis: May 15
Chicago: April 25
Boston: April 15
Seattle: March 15
Denver: May 5

Southern Cities

Atlanta: March 25
Austin: March 5
Los Angeles: Feb 15
Phoenix: Feb 15
Miami: Frost-free

Seeds to Start Indoors vs. Direct Sow

Start Indoors

Tomatoes
Peppers & eggplant
Broccoli & cabbage family
Basil & slow herbs
Celery
Onions & leeks

Direct Sow Outdoors

Carrots, radishes, beets
Beans and peas
Corn
Squash and melons
Cilantro and dill
Spinach and lettuce

Indoor Seed Starting Essentials

Good lighting: South-facing window or grow lights 2-4 inches above seedlings for 14-16 hours daily

Warmth: Most seeds germinate best at 70-75°F. Use a heat mat for peppers and tomatoes

Seed starting mix: Use sterile, light seed starting mix - not garden soil

Containers with drainage: Cell trays, peat pots, or recycled containers with holes

Humidity dome: Cover seeds until germination to maintain moisture

Week-by-Week Timeline Example

For a last frost date of May 1st, here's when to start each crop:

February 15 (10 weeks before)

Start peppers and eggplant

March 1 (8 weeks before)

Start tomatoes and broccoli

March 15 (6 weeks before)

Start basil, lettuce, and herbs

April 1 (4 weeks before)

Start squash and cucumbers (if starting indoors)

April 15 (2 weeks before)

Begin hardening off seedlings

Frequently Asked Questions

What happens if I start seeds too early?

Starting seeds too early results in leggy, weak seedlings that become root-bound before transplanting time. They may struggle to adapt outdoors and produce poorly. It's better to start slightly late than too early.

What happens if I start seeds too late?

Late-started seeds may not have time to mature before frost returns in fall. For warm-season crops like tomatoes and peppers, this means reduced harvest or no fruit at all. Fast-maturing varieties can help if you're behind.

Do all vegetables need to be started indoors?

No, many vegetables do better when direct-sown outdoors. Root crops (carrots, beets, radishes), beans, peas, corn, and squash prefer direct sowing. Indoor starting is mainly for slow-growing, heat-loving crops.

How do I find my last frost date?

Search 'last frost date [your city/zip code]' or check your local cooperative extension. This date is an average - actual frost can occur 1-2 weeks on either side. Container gardeners have flexibility since pots can be moved indoors.

When to Start Seeds Indoors?

Quick Answer