When to start eggplant seeds
Short answer: sow eggplant indoors 8 to 10 weeks before planting out, and wait until 2 to 3 weeks after your last frost to plant it outside. It is the most cold-sensitive of the tomato family.
At a glance
- Start indoors
- 8–10 weeks before setting out (UNH); UMN says about 8 weeks
- Set out
- 2–3 weeks after last frost (UNH), when night lows are consistently above 50°F (UMN)
- Germination temperature
- 70–75°F (Iowa State); UMN suggests 75–85°F on a heat mat
- Days to sprout
- 7–10 days (Iowa State); 13 days at 59°F soil, 5 days at 77°F (Harrington)
- Direct sow?
- No; grow from transplants
UNH = University of New Hampshire Extension; UMN = University of Minnesota Extension; Harrington = J. F. Harrington's germination data as published by Oregon State University Extension. Full links are under Sources below.
Your dates: eggplant seed-starting calculator
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How many weeks before the last frost?
University of New Hampshire Extension gives eggplant 8 to 10 weeks from seed to transplant and the latest set-out of any crop on its list: 2 to 3 weeks after the last frost. So you sow about the same time as peppers but plant out a little later. With an average last frost of May 10, you would sow indoors March 15 to March 29 and set plants out May 24 to May 31.
University of Minnesota Extension suggests about eight weeks indoors. Either way, eggplant is one of the first warm-season crops to sow and one of the last to go outside.
Germination
Harrington's germination data (published by Oregon State Extension) list a 60°F minimum soil temperature and an 85°F optimum for eggplant. Seedlings appeared in about 13 days at 59°F, 8 days at 68°F and 5 days at 77°F.
Iowa State Extension lists 70–75°F with seedlings in 7 to 10 days. UMN recommends a heat mat at 75°F to 85°F until emergence, then about 70°F soil. Sow a quarter inch deep in sterile, soilless mix and keep it evenly moist.
Growing on
- Thin or pot up after true leaves appear so seedlings stand 2 to 3 inches apart under bright light.
- Like peppers, eggplants may flower indoors. UMN suggests pinching off flower clusters until the plants are in the garden.
- When plants are about 5 inches tall and 8 to 10 weeks old, reduce watering and begin hardening off.
Hardening off and transplanting
Start with a sheltered spot and a couple of hours of sun, then increase exposure over a week or two. UMN says to bring eggplants indoors if night temperatures drop below 55°F during hardening.
The key warning from UMN: eggplants are much less cold-hardy than tomatoes. If they go out before overnight lows are consistently above 50°F, they can suffer chill damage and may never recover and bear fruit. Night temperatures below 60°F or above 70°F, or days above 90°F, can also cause poor flowering.
Space plants 18 inches apart in rows 30 to 36 inches apart, set them at the depth they grew in the pot, and install supports at planting. Black plastic mulch helps by warming the soil, but UMN advises not laying mulch before the soil has warmed in spring. Rotate away from tomatoes, potatoes, peppers, eggplant and tomatillos for three or four years.
Common mistakes
- Planting out with the tomatoes. Eggplant needs an extra week or so of warmth.
- Cold germination. Below 60°F, expect slow and patchy emergence.
- Too much nitrogen. UMN notes heavy nitrogen gives bushy, leafy plants that are slow to bear.
- Uneven watering. UMN links inconsistent moisture to bitter fruit, low yields and blossom-end rot.
Example schedules
The same timing rules applied to three different average last frost dates. Find your own date on the frost dates page, or check your zone planting calendar for typical ranges.
| Last frost | Start indoors | Plant out | Direct sow |
|---|---|---|---|
| Mar 15 | Jan 18–Feb 1 | Mar 29–Apr 5 | — |
| Apr 15 | Feb 18–Mar 4 | Apr 29–May 6 | — |
| May 15 | Mar 20–Apr 3 | May 29–Jun 5 | — |
Supplies
Optional. You can start seeds with very little gear; these are the items that make the steps above easier. Disclosure: some links on this site may be affiliate links; if you buy through them we may earn a commission at no extra cost to you. Learn more.
- Seedling heat mat with a thermostat: UMN recommends 75–85°F until emergence.
- Black plastic mulch: warms the soil for heat-loving crops.
- Short-season eggplant seed: UMN notes some varieties suit short summers.
Frequently asked questions
When do I start eggplant seeds indoors?
8 to 10 weeks before planting out (UNH). Because eggplant goes out 2 to 3 weeks after the last frost, that is about 5 to 8 weeks before your last frost date.
What temperature do eggplant seeds need to germinate?
Iowa State lists 70–75°F. Harrington's data give a 60°F minimum and 85°F optimum, with emergence in about 5 days at 77°F.
Can eggplant go out at the same time as tomatoes?
It is better to wait. UNH sets eggplant out 2–3 weeks after last frost versus 1–2 weeks for tomatoes, and UMN warns that cold nights below 50°F can stunt eggplant for the season.
Sources
- University of New Hampshire Extension — Growing Vegetables: When to Plant Your Vegetable Garden
- Oregon State University Extension — Soil temperature conditions for vegetable seed germination (J. F. Harrington data)
- Iowa State University Extension — Germination Requirements for Annuals and Vegetables
- University of Minnesota Extension — Growing eggplant in home gardens
- University of Minnesota Extension — Starting seeds indoors
Dates in the calculator and example tables use the University of New Hampshire Extension timings. Average frost dates are not guarantees; check the forecast before setting out tender plants. Last reviewed 2026-10-23. Found an error? Tell us.