How often should I add fertilizer to my waterings?

I have 2 autoflowering plants at 7 weeks. Both are showing signs of maturity(alternating nodes, pistils). I use Jack's All Purpose(20-20-20) and Blossom Booster(10-30-20) I haven't really had a chance to use the all purpose as one of my plants went from a nute burn to deficiency so I just played it say and used plain water. One of my plants currently has a nitrogen deficiency. I plan on using the blossom booster on after my next watering(tomorrow) of plain water. The instructions say use 1/4 tsp(per gallon) every watering or 1/2 tsp every other watering. Someone in my grow journal told me to only use nutes every other watering. Is it ok to follow the directions and use 1/4 tsp every watering? My other plant is fine, green growth, no yellowing, no red stems or anything. Thanks in advance

i wouldnt add fert every watering,,,,at 7 weeks i would stick with the 1 waterings of just water, then hit it with the 20-20-20 or whatever ,,if you see and yellowing in the plant then i would up the fert mabey a little bit,,,and always follow the mixture ratios on the fert bottle,,, but i would mostly let your plant tell you how often to feed and fert..you can always add boosters as your plant gets healthy and big..depending on how big you want them.....i like adding ORGANIC molaces to my 20-20-20 batch,,1tsp per gallon..very good for the soil..my opinon from actualy trying it..

Well I have a nitrogen deficiency right now. Leaves are yellowing then dying and stems are beginning to redden. It's a bit harder to take pics of the stems. Yea I've been interested in getting some of that, I might have to check my grocery store later today/tomorrow.