started growing today.

3 reggie seeds in styrofoam cups with miracle gro..
3 cfls 2,700 lumens each.. what nuts should i use?

top dress with cashews.

Or you could just give them water only if you MG has time release nuts in it. If not, you still should not need nuts for a good month. Plenty of time to research further.

how fast you think it'll grow under those cfls

Cashews are good to top dress with. Almonds work better I think. It's good to start with a plan. They can grow fine under cfl.