might be best t just wait till you harvest the others this time of year they wont get much light on the window sill n could poss end up with some stretching. Is there any way y can split y grow room ? or buy one of those small plastic greenhouses £9.99 from instore put y seeds in there under 18~6 light and buy some total blackout from greenshorticulture.co.uk its white on one side so good for reflecting light. I use one of those small green houses I have it in the attic its good during winter cos it helps keep the heat in also easy to cover to stop light getting out n no where near as expensive as a grow tent. I use envirolights with my plants but think with seeds the 400 would be best. Hope this helps