I moved all my plants to the basement because my greenhouse was awful!
They’ve been hanging out under 4′ long, 6500K LED lights now (link*), which seems to be working really well and costs about $10/month to run 5 of them, which is 1/5 the cost of heating the greenhouse. Basically, the 6 pack of lights I got for $50 paid for itself in a month and I don’t need to worry about things freezing because the basement is perpetually 60F. It’s a lovely setup.
A lot of my plants are actively perking up or flowering after being removed from the wild temperature swings of my greenhouse. So if people see ‘basement lights’ on my plants, just know that this is my setup I’ll be using until it gets warmer :)
*Full disclosure: the link above is an affiliate link, so I’ll make a small profit from the sale with no extra cost to you)