Long-season warm crops are started indoors several weeks before the last frost and set out after it — tomato and tomatillo about six weeks ahead, pepper and eggplant about eight. Basil, six.
Promising · suboptimal if ignored → advise
How it works
A frost-tender crop with a long days-to-maturity cannot mature if it is only direct-sown after the last frost — the frost-free window is too short. A head start under cover buys the weeks the season lacks; the seedling is set out only once frost has passed — the transplant date is still frost-gated.
The evidence
Evidence: confirmed against 2 sources in the research-based literature.
the 2 sources
University of Minnesota Extension, 'Starting seeds indoors', extension.umn.edu/planting-and-growing-guides/starting-seeds-indoors: seed-starting chart gives tomato '5-6 weeks' and pepper and eggplant '9 weeks' before the outdoor planting date (warm crops set out after the last frost). Read 2026-07-19 (LLM-summarised); read by the maintainer 2026-07-25, which is the read that promoted this rule. Note what the corpus's per-crop values do with the sources: tomato 6 sits at the top of Minnesota's '5-6 weeks' and inside Illinois's '6-8'; pepper and eggplant 8 sit BELOW Minnesota's '9 weeks' and at the top of Illinois's '6-8'. They are a reconciliation of two published ranges, not a figure either source prints.
University of Illinois Extension, 'When should I start my seeds?' (2023-02-10), extension.illinois.edu/blogs/good-growing/2023-02-10-when-should-i-start-my-seeds: peppers, tomatoes, and eggplant started '6-8 weeks before the last frost'. Read 2026-07-19.
Plants this fires on
- Amaranth
- Artichoke
- Basil
- Borage
- Buckwheat
- Butternut
- Common Bean
- Corn
- Cosmos
- Cowpea
- Cucumber
- Edamame
- Eggplant
- French Marigold
- Lima Bean
- Marjoram
- Melon
- Nasturtium
- Okra
- Pepper
- Rocky Mountain Bee Plant
- Runner Bean
- Sorghum
- Summer Savory
- Summer Squash
- Sunflower
- Sweet Potato
- Tomatillo
- Tomato
- Watermelon
- Winter Squash
- Zinnia
Change history
Every change to this rule is one commit. This is what the project's version history records — the date and the reason — not a summary of it.
- Corpus: another rule here verified - the maintainer read the seed-starting charts
- corpus: add another rule here, start-indoors lead for warm transplants (Promising, unverified)
Cite this page
Milpa Gardens. "Long-season warm crops are started indoors several weeks before the last frost and set out after it — tomato and tomatillo about six weeks ahead, pepper and eggplant about eight. Basil, six." Evidence grade: Promising. https://milpa.garden/rules/long-season-warm-crops-started-indoors-several/
A garden-planning corpus: every claim states its evidence grade and links its sources on the page. Cite it with the grade, and add the date you read it.