Can I use a seedling mat to raise the atmospheric temperature to grow polychilos?

[Roberta]

They will be more forgiving. The Phal hybrids likely will be OK, some of the species may still be unhappy. You may want to move all of them away from the cold window. If you need more light, you can easily enough add supplemental light. If you're just supplementing natural light (as opposed to growing in an otherwise dark area) you don't really need fancy grow iights, any full-spectrum LED light will do.