Clones with small root system needs boost nutes

I got some Purple Kush clones and they have been struggling for 3 weeks to get anything but the barest of root system going. The leaves are very small and not very green. I have great lighting and been hitting them with 2 tbs B1 and 2 tbs fish emulsions. This same treatment grew them great last time but that time they had lush roots. I think they pushed these out the door weeks before they were ready for sale. So what can I give them to get their roots going?

What is your climate like?

Do you have pics of the plants?

The bigger ones are autoflowers which are doing OK. The small ones are the PK clones. Light is a 600 - 1000w variable. I tried it on 600 and 1000 for a week. I'm not burning them so I'll stick with the 1000. The pic makes them look more light stressed then they really are. I just started giving them CO2 which the autoflowers responded to but not much from the clones. The clone's roots are just kind of a small clump of cobweb, none are thick like my last clones had when they were young.