to look up on a search engine "cloning" Many plants can be cloned, not just mj. Knowledge of an all around basis will help you out a lot.
You shouldn't ever fail if your using a root gel, but I don't like to because at least EVERY SINGLE one i have ever bought says do not use on plants you intend to eat....so why would you use it on something your going to smoke...I once asked a question about that just to see what other people's opinions were...
Someone actuallyy told me that it will flush out by the time you harvest...but i don't think that is true, you just attached this subtance to the very base of where all your roots are going to grow out of...ITS THERE FOR THE LIFE OF THE PL ANT, in my opinion... and why risk it when you could just stick it in some water and it will root, and then put it into your medium...though that is much harder to do with rockwool or any other cocunut husk material...i would recommend just sticking it into the rockwool, it will root.
other good tips to know are that you are trying to take a plant that is in the mindset of GROW GROW GROW...upwards...to i need to grow roots down there.... so you don't half to, but especially if your not going to use a root gel you need to flush your plants for a week or two before you clone them. it will take out all the nitrogen..nitrogen is what tells the plant to grow up...so flush it out and it will stop growing...that way when you take a clone from the plant that clipping will now have the mindset of...ok i don't need to spend my energy growing upwards...i can get some roots in first.
trimming the lowest set of leaves in half is also done to achieve the same thought process, not getting rid of nitrogen, but you are sending the energy elsewhere... most botany and horticulture courses and especially biodynamic gardening will recommend clipping the leaves in half, I do it every time and am always successful
Putting them in a humidity dome will help create condensation and moisture on the leaves...which is the same thing is flushing your plants it keeps them thinking...ok dont grow...first get roots. so mist them a couple times a day in their dome. you don't have to mist if you can see enough condensation is being created...its all really play by ear. def. will depend on how much heat your lights are putting out.
the lower sets of leaves on your plant will root faster then the top parts of the plants.