Grow Light for Impatiens Seedlings: Light to Sprout
A grow light for impatiens seedlings matters from the first day. University of Minnesota Extension notes impatiens seeds require light to germinate. That means the tray goes under the light right after sowing, not after the seedlings appear. Warmth, moisture plus close light give an even stand of seedlings.
The short answer
Sow on the surface, cover lightly with vermiculite, then set the tray under a light at once. University of Minnesota Extension suggests 4 to 6 inches above seedlings for 16 to 18 hours a day. Germinate walleriana types at 72 to 77 F, then grow them at 65 to 70 F.
Why do impatiens seeds need light?
Light is a must for these seeds, per University of Minnesota Extension. It advises planting on the media surface plus covering with vermiculite. A plastic cover holds moisture in. Walleriana seeds germinate in 5 to 15 days at 72 to 77 F. New Guinea seeds take 12 to 25 days at 75 to 80 F.
| Type | Start indoors | Germination | Source |
|---|---|---|---|
| Walleriana | 10 weeks before planting | 5 to 15 days at 72 to 77 F | University of Minnesota |
| New Guinea | 12 weeks before planting | 12 to 25 days at 75 to 80 F | University of Minnesota |
| Both, after germination | Grow at 65 to 70 F | Not given | University of Minnesota |
| Seedlings | Light 4 to 6 inches away | 16 to 18 hours a day | University of Minnesota |
Source: University of Minnesota Extension.
How much light do seedlings need after sprouting?
University of Minnesota Extension suggests 4 to 6 inches between seedlings and the light, moved up as they grow. It suggests 16 to 18 hours of light a day for seedlings. After germination, both impatiens types grow at 65 to 70 F. Close light gives compact plants.
When should impatiens go outside?
Clemson Extension advises starting impatiens six to 10 weeks before planting outside. It suggests hardening off seedlings after the last chance of frost. University of Minnesota Extension notes impatiens can go outdoors once soil temperatures are above 60 F. North Carolina State Extension notes seeds may be sown indoors in late winter.
How to: step by step
- Sow 10 to 12 weeks before planting, by type.
- Set seeds onto the mix surface.
- Dust with vermiculite plus add a plastic cover.
- Place the tray under the light at once, 4 to 6 inches away.
- Run the light for 16 to 18 hours daily.
- Plant out when soil tops 60 F.
Troubleshooting
Seeds not sprouting: buried too deep or left dark. Sow on the surface under light.
Seedlings collapsing at the base: damping off. Clemson Extension notes it can occur during germination. Use a fresh seed starting mix.
Stretched seedlings: light too far away. Lower it to 4 to 6 inches.
For related reading see cannabis seedling light schedule, damping off in cannabis seedlings plus leggy cannabis seedlings. Kind Seed Co also stocks cannabis seeds.
Sources
- Impatiens, University of Minnesota Extension
- Impatiens, Clemson Extension
- Impatiens walleriana, North Carolina State Extension
- Lighting for indoor plants and starting seeds, University of Minnesota Extension
FAQ
Do impatiens seeds need light to germinate?
Yes. University of Minnesota Extension notes impatiens seeds require light to germinate. It advises sowing on the media surface plus covering with vermiculite, then using a plastic cover to hold moisture. Put the tray under the grow light right after sowing rather than waiting for seedlings to appear.
How warm should impatiens seeds be?
University of Minnesota Extension notes walleriana seeds germinate in 5 to 15 days at 72 to 77 F. New Guinea seeds germinate in 12 to 25 days at 75 to 80 F. After germination, both types can be grown at 65 to 70 F under the lights until planting time.
When should impatiens seeds be started?
University of Minnesota Extension suggests starting New Guinea seeds 12 weeks before the outdoor planting date. Walleriana seeds need less time and can start 10 weeks before. Clemson Extension gives a range of six to 10 weeks. Count back from the date when your soil warms above 60 F.
How far should the light be from impatiens seedlings?
University of Minnesota Extension suggests 4 to 6 inches between seedlings and the light. It advises moving the light up regularly as the plants grow. It suggests 16 to 18 hours of light a day for seedlings. A timer holds that schedule steady from one day to the next.
Why do impatiens seedlings fall over?
Clemson Extension lists damping off during germination among impatiens diseases. Seedlings that collapse at the soil line often point to it. Start with a fresh mix made for germinating seeds, as University of Minnesota Extension advises. Stretched seedlings can also flop, so check that the light sits close enough.
