Temps for seedlings

asaump · March 29, 2018

First time seed starter. I started my sweet peppers last week in my basement and they came up in 6 days. I started on a heat mat under a dome with temps about 80-85 degrees. I have now removed the dome and took them off the mat. They are under lights (LED - 6500k). The air temp hovers around 50 degrees in the basement. The LEDs do not seem to affect the air temp very much. Maybe a bit of heat just below the lights. My temp gauge sits on the shelf beside the flat. That is where I get the 50 reading from. Will these little guys survive in the colder temps until the basement warms up if/when spring gets here?

velikipop · March 29, 2018

I think t might be just a bit too cold for them. Look for signs of stress such as droopy leaves or yellowing on the new growth.

Cole_Robbie · March 29, 2018

They might survive, but like velikipop said, they will be cold. You could make a plastic enclosure around them to try to trap a little heat, or add other lights. The low level of heat is usually an advantage with LED lighting, but not so much so when starting seeds in a cold basement. Maybe you could place the heat mat in the plastic chamber, but not set the flat directly on it.

asaump · March 29, 2018

Thanks for the quick replies. Sounds like a mini greenhouse in the basement as a project this weekend. A temp controller was just delivered today with a larger heat mat so I'll work with that to see what I can come up with.

Cole_Robbie · March 29, 2018

You can make it as nice as you like. Just stapling up plastic or a tarp will help. Or if you want to put a little more into it, foil-faced styrofoam insulation sheets make great boxes. I have used foil furnace tape to hold them together. The tape is even strong enough to make hinges, if you just tape a panel on one edge.

A styrofoam box would hold heat very well, enough that the LEDs should make it as warm as you like. Since you have a temp controller, you could wire that to an exhaust fan up top, so that you vent when it gets hot. You'll need a fresh air exchange every so often anyway. You would want a passive intake at the bottom, like a dryer vent turned backwards.

asaump · March 29, 2018

Well, I just happen to have a sheet of 1/2" styrofoam board in the garage and a partial roll of radiant heat reflective foil. Also have a couple of PC fans not being used. Great idea.

asaump · March 29, 2018

So if I make this out of the Styrofoam do I call it a 'pinkhouse'?

March 29, 2018	#1
asaump Tomatovillian™ Join Date: Jan 2018 Location: Maine, 4b Posts: 73	Temps for seedlings First time seed starter. I started my sweet peppers last week in my basement and they came up in 6 days. I started on a heat mat under a dome with temps about 80-85 degrees. I have now removed the dome and took them off the mat. They are under lights (LED - 6500k). The air temp hovers around 50 degrees in the basement. The LEDs do not seem to affect the air temp very much. Maybe a bit of heat just below the lights. My temp gauge sits on the shelf beside the flat. That is where I get the 50 reading from. Will these little guys survive in the colder temps until the basement warms up if/when spring gets here? __________________ Ken

March 29, 2018	#2
velikipop Tomatovillian™ Join Date: Dec 2006 Location: Langley, BC Posts: 768	I think t might be just a bit too cold for them. Look for signs of stress such as droopy leaves or yellowing on the new growth. __________________ I'll plant and I'll harvest what the earth brings forth The hammer's on the table, the pitchfork's on the shelf Bob Dylan

March 29, 2018	#4
asaump Tomatovillian™ Join Date: Jan 2018 Location: Maine, 4b Posts: 73	Thanks for the quick replies. Sounds like a mini greenhouse in the basement as a project this weekend. A temp controller was just delivered today with a larger heat mat so I'll work with that to see what I can come up with. __________________ Ken

March 29, 2018	#6
asaump Tomatovillian™ Join Date: Jan 2018 Location: Maine, 4b Posts: 73	Well, I just happen to have a sheet of 1/2" styrofoam board in the garage and a partial roll of radiant heat reflective foil. Also have a couple of PC fans not being used. Great idea. __________________ Ken

March 29, 2018	#7
asaump Tomatovillian™ Join Date: Jan 2018 Location: Maine, 4b Posts: 73	So if I make this out of the Styrofoam do I call it a 'pinkhouse'? __________________ Ken

March 29, 2018	#3
Cole_Robbie Tomatovillian™ Join Date: Jun 2012 Location: Illinois, zone 6 Posts: 8,407	They might survive, but like velikipop said, they will be cold. You could make a plastic enclosure around them to try to trap a little heat, or add other lights. The low level of heat is usually an advantage with LED lighting, but not so much so when starting seeds in a cold basement. Maybe you could place the heat mat in the plastic chamber, but not set the flat directly on it.