Insulated box for seed starting in cold basement

[CtGrower]

I have a bakers rack for seed starting in my unheated basement. The temperature has been a constant 48ish degrees. Last year the seedlings did not do well, and I'd like to try to create a warmer environment for them. I'm thinking of using a foil backed foam board product with R6 to make a box around my bakers rack to retain heat from my LED lights and heat pad. I envision cutting the foam to put on a top shelf and bottom shelf and figuring out a way to attach the foam to the sides and back and front of the shelves. I know I should probably have a fan running somewhere tbd. Has anyone else tried something like this? Do you think this would be beneficial for seedlings? I'd like to start warm season crops like tomatoes and peppers in the basement.

[bower]

I have a cold basement too, but 48ish is a bit cold for tomatoes and peppers.
Anything surrounding your seed setup that reflects the heat and light is going to help. White paint, foil, etc.
Insulation will probably keep a small space heated enough with lights and heat pad inside.
Some people make 'grow tents' and seem to get that to work, but a shelf of the right size should be easier to manage. I don't know what grow tenters do about ventilation.

[ddsack]

You can get small clip-on usb powered personal fans for around $10 and up that would work for smaller enclosures, but might still need a few small openings for fresh air. In my unheated greenhouse, I partition off part of it with mylar(?) space blankets clothspinned to wires attached to screw eyes in the greenhouse frame, to form a reflective box across the top and sides. I only use it at night when I expect to need to run an electric oil filled fin heater to keep the greenhouse from freezing. The clothespins make for easy disassembly. There are unintended gaps in coverage here and there which serve for ventilation. I don't use a fan, but some gaps at the bottom and top, along with the heater keep the rising air flow moving naturally. There are likely lots of creative solutions depending on the size of the area you want to heat. I have seen fairly rigid rolls of reflective insulation material over bubble wrap that could be cut and duct taped together to enclose smaller areas. Just a stroll through some builder supply stores like Menard's or Home Depot etc. will give you some ideas.

[CtGrower]

You can get small clip-on usb powered personal fans for around $10 and up that would work for smaller enclosures, but might still need a few small openings for fresh air. In my unheated greenhouse, I partition off part of it with mylar(?) space blankets clothspinned to wires attached to screw eyes in the greenhouse frame, to form a reflective box across the top and sides. I only use it at night when I expect to need to run an electric oil filled fin heater to keep the greenhouse from freezing. The clothespins make for easy disassembly. There are unintended gaps in coverage here and there which serve for ventilation. I don't use a fan, but some gaps at the bottom and top, along with the heater keep the rising air flow moving naturally. There are likely lots of creative solutions depending on the size of the area you want to heat. I have seen fairly rigid rolls of reflective insulation material over bubble wrap that could be cut and duct taped together to enclose smaller areas. Just a stroll through some builder supply stores like Menard's or Home Depot etc. will give you some ideas.

I thought about using the reflective bubble wrap, but it has very little conductive R value. I'd like to maintain a delta temp of about 15 degrees when the lights are on during the day, so calculated that Rvalue of 6 would work. The temperature would drop at night when the lights are off.

Good thought about the usb fan. I was thinking of not taping up the sides so that the foam insulation could be taken down and stored. This would also leave it 'leaky' so that perhaps some air exchange would happen as well.

[rxkeith]

is it possible to start your seeds in a warmer environment than a 48 degree basement?
my basement is probably colder than yours. plants don't go down there until they have
grown a bit and i need to slow them down before plant out time. i have started my seeds
in the past on trays by or over a heat vent, on top of a cast iron radiator, and in this house
underneath our wood stove we use to heat the house. once sprouted, they go on a plant stand
in an upstairs bedroom under lights. tomatoes, and peppers don't usually go down my basement
until the beginning of may.


keith

[CtGrower]

is it possible to start your seeds in a warmer environment than a 48 degree basement?
my basement is probably colder than yours. plants don't go down there until they have
grown a bit and i need to slow them down before plant out time. i have started my seeds
in the past on trays by or over a heat vent, on top of a cast iron radiator, and in this house
underneath our wood stove we use to heat the house. once sprouted, they go on a plant stand
in an upstairs bedroom under lights. tomatoes, and peppers don't usually go down my basement
until the beginning of may.


keith

That is a possibility. I was hoping to not have to move my lights and bakers rack upstairs. You bring up good points about germinating them in a warm environment first and then moving them to the cooler environment when they are bigger. I will see if I can work something out upstairs. I still would like to try to see if I can create a warmer environment downstairs as well since there is more room. Thanks

[JayneR13]

I'm dubious that the frost-sensitive stuff, such as tomatoes, peppers, cukes, and squashes would like this. They tend to prefer temps in the 70F range and think it's winter in the 50Fs.

[CtGrower]

@JayneR13 I figured out a way to bring lighter weight shelves upstairs so I will germinate seeds in the warmer room and will bring seedlings downstairs to the cold after they have established themselves to at least 1 or 2 set of true leaves. I probably will be selective in which plants I bring downstairs. I have heard that tomatoes can benefit from cold nights as long as temps get to the 60's during the day. I will hold off on putting peppers down there since I know they like temps in the 70's. I am hopeful that I can increase the temp to about 65 during the day with insulation or a heater. Good news is that the temp is now 50F!