How long is it till you start putting chemicals on your plant speaking in week periods

A customer has a question and I hope we can get some opinions on it, thanks

I have question, when growing inside you talk about 3 major chem. nitrogen,phosprus, and potassium, then you talk about other chemicals like small amounts of iron and others,when growing inside and you have 10 week growing period, how long is it till you start putting chemicals on your plant speaking in week periods ,you wait for one week or do you start right away then how many weeks do you wait before you put in the posperus,then the larger amounts of potassum, then the smaller traces of the other chemicals are going in the whole time, but could you break down per week inside growing with plants like criticalmass, gold leaf,feminized seeds.

Usually your nutrients are going to come in a bottle premixed. Although there are some that do like mixing their own, for ease of use. Its simpler to buy stuff that has worked for others. Take fox farm trip for example.
You would wait until your plant is 1-2 weeks old before you begin to feed. The you can follow the feeding chart. Start with a lower dose of nutrients to start, then work your way up.

I start fertilizing at two weeks. BUT…at very low levels. Less than 10% of mfg’s feeding schedule. Following the feeding schedule mfg’s provide will get you burnt plants.
Adjusting as the plant shows it is needing more. I seldom feed more than 40% of feeding schedule.

Nutrients will provide all the food needed for a healthy crop. There are many mfg’s of nutes. Checkout the listings on Amazon, Ebay, even Walmart and Home Depot are selling. Usually these come in 3 part liquids…Micro, Grow and Bloom. Several mfgs sell a three part set for $30.
Download and read the Free Grow Book on this site. Lots of good information. You can also read some of the other postings here.
General Hydroponics, Emerald Green and Advanced Nutrients are some of the many mfgs.