You have good results from top dressing Van. Where do I study top dressing? What, when, and how much in different stages of growth are questions. Is it a seat of your pants thing you got from experience, or is there info in a book or somewhere?
So here is my approach to top dressings brother. There are some basics with my soil...lots of minerals, some organic matter, a lot of calcium (always a high demand for Ca with high end LED lights) and then remember what you are feeding through top dressing ultimately isn't feeding the plant, its feeding the herd. I want to supply them with stuff that they can convert into the appropriate thing needed by the plant at that time. The plant roots will talk with the herd and tell them what they need. The herd will do the work and give the roots/plant what it needs in exchange for what the plant provides the herd. Organic growing is all about the herd and not about the plant. The plant is just a picture of the health of your soil.
Obviously I don't don't want to top dress blood meal (high in N) during flower. Vice verse, doesn't make much sense to top dress in all seabird guano (high in P) during veg. So I like to say keep the basics aligned with the appropriate life cycle of the plants.
There are some things that will always be good. EWC (Earth Worm Castings) and Kelp Meal are great for any time. Kelp meal has 70+ micro nutrients. You could have good results with top dressing with just those two. I really go off gut feeling based off how I see them growing. Does it seem like the plant is growing with a deficiency of some sort? If so, I want to add that in as soon as possible. Does it look like there is a lack of energy in the soil? If thats the case, I am chasing the bio activity and not a specific result.
Really if you have a good soil to start with, it won't take much. Also keep in mind everything I do, I do with the mind that the soil is going to be reused. Anything I put in through top dressing that doesn't get used immediately, will be there for the next grow.
I have been playing around a little with a new product that I got back at the Harvest Cup. Its called Natures Pride Veg. They have three different top dressings they sell....the Veg, Bloom, and Flower Finisher. The veg is applied in veg and the first 2 weeks of flower. Then you go to the Bloom for a few weeks and then finish with the FLower Finisher.
I have only really only used the veg, but I really like it. Its got a lot of good stuff you don't see in everything....amino acids, humic acid, bio-char, and lots of other good stuff. I have seen some great reactions out of my plants when using a tablespoon worked into the soil every week to ten days.
I have used the other stuff...the Bloom and FLower Finisher but I don't see the same reaction from the plant so I can't confirm if it works as well. I picked up a 5 lb pack of the Veg stuff off the Zon for about 30 bucks. It works well enough that I am going to try and replicate something similar since I have almost all the amendments already....just need to work on ratios.