Hello i have 9 or 10 plants and some of them i puned 2 weeks ago and the bushed back out...i didnt take all the leaves of but i pruned it again and took quite a bit off the plant They still look healthy and still have leaves, but i guess my question is how long should i keep pruning...does it REALLY help my yield a bunch...and can a plant be TOO YOUNG to prune?
This is an excellent question, one that if it leads to good techniques can impressively increase the yield of your plants grown indoors. The short answer, misleading though it may be, is 'yes.' It certainly is possible to overprune. However, I also disagree with those who say less is always better.
A thread I started on this topic:
Topping and Training Tech for Yields and Quality
The bottom line is to begin with the end in mind, a lot like chess. If all you do is randomly move your pieces around, a player who knows the goal of attrition of the opponent's forces, leading to checkmating your King will crush you in short order. So it is with topping, training, pruning, whatever you want to call it.
The goals are these: increase budding sites, shape the plant to best utilize the available environment(usually lighting placement is the deciding factor), reduce possibility of disease attacks.
To increase budding sites, you top, or 'FIM', although the two are nearly indistinguishable. You can also 'supercrop', which is merely bending the topmost dominant branches until they break over, which then supplies more nutrients to the buds directly beneath. Keep in mind that these are all techniques to gain the ultimate goal of increasing budding sites; I use them all as appropriate, to gain the number of sites I seek.
To best utilize the available environment, first you need to make a choice; if outdoors, little of this matters, as the plant is already evolutionarily equipped with the tools to maximize its growth outside. If inside, you need to train the plant to best use the light source. If your lights are above, then you need to top, bend and train the plant so it presents a broad, roughly level top surface to the light source. ScrOG is a good approach to do this, especially as it provides a guide to the grower to help him/her level the canopy and present the most effective surface to the bulb. You do not want a single- or a few- tall spires of growth, as they will grow too close to the bulb, injuring themselves and shading the rest of the plant. If the light source(s) are to the sides, as in 'vertical' style grows, then you need to ensure the plant grows well in all directions to take maximum advantage of the light placement.
To reduce disease, you'll want to remove a lot of undergrowth; the spindly, larfy, weak, pale stuff that never amounts to good quality yield and takes up nutrients the plant could be better using in the canopy above. This understory removal is often called 'lollipopping', as the visual evokes resembles the plant a bit; bare stalks reaching up into a layer of lush, bushy canopy ideally situated to get the best use of the indoor light.
The key is less about 'how much' to prune- the answer here is simple; 'as little as possible to achieve your goals'- and more about what you want your plant to look like once it's done and ready for harvest. Good topping and training practices will prompt the careful grower to do some of this early, as mentioned in my thread, some a little later, and even some- especially 'lollipopping' or understory removal, in early flower.
This takes time and experience, which comes from practice and knowlege of the specific growth characteristics of the strains and phenos you're growing..