seed starting soil temp?

[homebrewer]

Hi everyone. I'm new to this, so I hope you don't mind the newbie questions. I started 16 cells last week and yesterday a few of them germinated. I put them under 4 100w (equivalent) CFL bulbs. Two at 6500k and the other two at 2700k. The lights are about 4-5 inches above the top of the stems. The flats are in an aluminum roasting pan in a bathtub we never use. The bulbs are generating some heat so I wanted to check the temp. The air temp at plant level is about 75F, but the soil temp has shot up to 90F. Thee is no heat source other than the bulbs. Is this normal? Will the high soil temp hurt the seedlings? Thanks for your help.

[applestar]

Sounds about right for eggplants and peppers to germinate, a bit higher than needed/ideal for tomatoes and too hot for seedlings after germinating. What are you growing?

[imafan26]

It is probably the tub and foil pan. They conduct heat and you probably don't have a fan either for air circulation. You could probably remove the lower lumen bulbs and still get enough light for now. The light would only be on for 14 hours so the soil will have some time to cool off a bit. Open the window a bit to let more cold air in. Try to get the air temp between 65-70 degrees it should help. As the plants grow the lights will go higher so there will be less direct light heating the tub and the pan.

[applestar]

I was thinking about what you advised the new member from Phillipines @imafan -- what about putting the pan on a riser -- maybe cooling rack or roasting rack, broiler pan....?

[applestar]

FWIW, these are also good temps for starting cucurbit seeds, especially melons and watermelons, as well as sprouting and growing sweet potato slips.

[homebrewer]

Thanks for all the input. I am growing...
Tomatoes
Green/Red Peppers
Summer Squash
Cherry Tomatoes
Watermelon
Cantaloupe

nothing too exotic. I will try the fan idea and maybe get rid of some of the foil.

[mauser]

For future reference all you need to start inside from that list are the peppers and tomatoes.