First time grower seeking advice!

(3 fems) 4 months old, in flowering for lil over 2 months, fed with fertalizer for 3 water cycles now. Watered every 4 days with a gallon of water. Running a humidifier to keep climate for humidity 60-70% and 70-80 temp. The soil has fertalizer in it, they are in 5 gal buckets.
Had some mishaps, They went root bound had to trasnplant, they seemed to pull outta that ok. They were in a green house first then moved to outside b/c of algae on top of the soil. Crushed by closet door, bent them at the 90 degree angle, one stock snapped. After all that they seem to be ok, pics incolsed.
Lighting went from Sun, to halogen, to HPS now 150 HPS bulb.
Flowers are filling out, with major crystals and hairs are starting to turn orange.

Questions:

1) What are trichs, someone told me to get a microscope and find out all i could on them...What are they?

2) How long til i should harvest them? If i let them go too long will they loose yeild and potency?

3) Am i watering to often or not enough? Am i watering them too much (ex:gallon/4-5 days with nutrients everyother water)?

Any advice would help. I will check to see if anyone has any questions! Thanks