Sadly not YA. in the dark they will just grow really tall and die early. If it were me I'd plant them out and hope for a mild late summer /early autumn for them to flower then.

Sowed mine back early April, after all the warm weather you would think they would be bigger, but mine are the same size as yours, just going to go for it and see what happens.

Cleomes are strange i did them one year and i had about 40 of them and they grew full size and didn't bolt. I tried for the next 10 years with no real success. It doesn't help when you get conflicting info on the web about how and when to germinate them. I've read info that says you can download them as late as may which i don't believe and i have info that says as early as possible febuary. Mostly i get seeds that germinate easily but don't grow or really slowly and don't have greenhouse to transfer them so they sit there it's too cold to it them out. And they just don't develop.

Look for warm, sunny microclimates in your garden: south or west side of a wall, at the south or west edge of a tree canopy, or shrub, etc.

My cleomes never get big enough to transplant it's too cold in February to it them out so they sit there until after frost's and never develop but i will keep trying i now have a conservatory to start them off early with plenty of light before it was a kitchen window cill with no overhead light i think that these plants need maximum light.