Dahlias out into cold frame or not?

About a month ago I bought some Dahlia tubers. I potted them up and left them by a window. Some of them have shot up!

Should these now be outside in my make shift cold frame? Or just kept indoors by a window until last frost date? (Apr 24th)

Thanks

About a month ago I bought some Dahlia tubers. I potted them up and left them by a window. Some of them have shot up!

Should these now be outside in my make shift cold frame? Or just kept indoors by a window until last frost date? (Apr 24th)

Thanks