What are these little green things in the soil of my peppers. Should I be worried? They were planted 7 weeks ago. I've since moved them into larger containers, and put more soil in as I think they were getting cramped in the Styrofoam cups. Are they turning purple because of some sort of nutrient deficiency? Should I put some sort of fertilizer in them? Any recommendations?
Your peppers aren't doing too badly. I am seeing over watering, not enough ventilation (fans blowing) and it is the perfect time to fertilize. Have you fertilized at all with anything?
I had a tray of 4" potted peppers and got a 3 foot string of dried peppers!
How much light do they get? Pick up one of those pots to feel the heft. Water only when that weight is obviously lighter. Don't allow the bottom of the pots to sit in water.
That green stuff is fungus, this means you are watering way too much. Scrape it off and only water when those pots feel LIGHT.
Osmocote 14-14-14 is the safest easiest balanced fertilizer newbies should use! Use HALF of what the directions tell you. You'll only need one maybe two applications the entire season.