Grow Light for Eggplant Seedlings: Warm Bright Starts
A grow light for eggplant seedlings gives these warm season starts the bright overhead light they need through long indoor weeks. University of Minnesota Extension advises bright overhead light, warm soil plus a start about eight weeks before planting out. Close lights plus warm trays give stocky plants.
The short answer
Hang the light close plus run it on a timer. Utah State University Extension suggests cool white fluorescent tubes 2 to 3 inches above the plants for 14 to 16 hours a day. Germinate seeds warm, then grow seedlings at 65 to 75 F until nights outside stay above 50 F.
How much light do eggplant seedlings need?
University of Minnesota Extension notes that without enough bright light directly overhead, the stems lean over. For tube lights, Utah State University Extension gives a range of 2 to 3 inches above the leaves for 14 to 16 hours daily. Illinois Extension advises 18 hours at most for seedlings. Raise the light as the plants grow.
| Stage | Guide | Detail | Source |
|---|---|---|---|
| Germination | Heat mat at 75 to 85 F | Until emergence | University of Minnesota |
| Seedlings | 2 to 3 inches away | 14 to 16 hours | Utah State University |
| Seedlings | A few inches away | 18 hours at most | Illinois Extension |
| Transplant size | 6 to 9 leaves | 5 to 8 inches tall | Utah State University |
Source: University of Minnesota Extension, Utah State University Extension plus Illinois Extension.
Why do eggplant seeds need warmth?
Eggplant is a warm season crop. University of Minnesota Extension suggests a heating mat that holds the flat at 75 to 85 F until seedlings emerge. Utah State University Extension germinates seeds at 80 F, then grows them out at 65 to 75 F. It notes eggplants are very sensitive to cool temperatures.
When should seedlings move outside?
Utah State University Extension allows 8 to 10 weeks to grow transplants. It notes stocky, dark green plants with 6 to 9 leaves that stand 5 to 8 inches tall grow most rapidly. University of Minnesota Extension advises waiting until nighttime lows stay above 50 F. It suggests easing plants into sun over a week or two.
How to: step by step
- Sow seeds about eight weeks before planting out.
- Place the tray on a heat mat at 75 to 85 F.
- Hang the light 2 to 3 inches over the seedlings once they sprout.
- Run the light 14 to 16 hours daily.
- Thin seedlings to 2 to 3 inches apart after true leaves appear.
- Harden off when nights hold above 50 F.
Troubleshooting
Slow germination: cold mix. Use a heat mat at 75 to 85 F.
Leaning or leggy seedlings: weak light from above. Lower the lamp to 2 to 3 inches.
Flowers on indoor plants: plants are ahead of the garden. Pinch off the flower clusters until planting.
For related reading see cannabis seedling light schedule, seedling heat mats for cannabis plus hardening off cannabis seedlings. Kind Seed Co also stocks cannabis seeds.
Sources
- Growing eggplant in home gardens, University of Minnesota Extension
- How to grow eggplant in your garden, Utah State University Extension
- Supplemental lighting for indoor seed starting, Illinois Extension
- Grow lights for starting seeds indoors, University of Maryland Extension
FAQ
When should eggplant seeds be started?
University of Minnesota Extension advises starting eggplant seeds about eight weeks before planting them outside. Utah State University Extension allows 8 to 10 weeks to grow a transplant. Count back from the date when nights in your area stay above 50 F, then sow so the plants reach size on time.
How warm should the soil be?
University of Minnesota Extension suggests a heating mat that holds the flat at 75 to 85 F until seedlings emerge. It notes warm soil is better than cool. Utah State University Extension germinates seeds at 80 F, then grows the seedlings on at 65 to 75 F under the lights.
How far should the light be from eggplant seedlings?
Utah State University Extension suggests cool white fluorescent tubes 2 to 3 inches above the plants. University of Minnesota Extension notes the stems lean over without enough bright light directly overhead. Raise the light as the plants grow so the gap stays small, and check the height every few days.
How many hours of light do eggplant seedlings need?
Utah State University Extension suggests lights on for 14 to 16 hours a day. Illinois Extension uses an automatic timer and advises no more than 18 hours for seedlings. A timer holds the schedule steady from day to day, so the plants get the same light without depending on memory.
How big should transplants be?
Utah State University Extension notes stocky, dark green transplants with 6 to 9 leaves that stand 5 to 8 inches tall grow most rapidly. University of Minnesota Extension advises planting out only after nighttime lows stay above 50 F. Ease the plants into full sun over a week or two first.
