You really want a healthy well established plant before you clone off it. I take cuttings just before I turn plants to bud. They are about 2.5' to 3' tall by then and have lots of lower branches to use as cuttings.
You can start taking clones as soon as the plant has enough vegetation to spare a couple of branches. Three to four weeks is no problem as long as the cuttings have sufficient stems.
i usually wait till i have a nice sized side branch...or a taller top that i could take off. there really iant a set time that its ok..just as long as you have enough for a clone to survive and the original plant to keep growing
I'm gonna hop in with a question too. I have some pretty bushy plants but I'm keeping them short due to space, I don't really want to cut a whole arm off so the pieces I would cut are very short, like 2.5, 3 inches. Does the length of the clipping matter? As long as I have a stem properly prepared it should root? I'm flipping to flower probably in less than a week.
Okay I'll wait 2 more week because she Just started recovering from losing her two biggest leaves due to me being stupid. Heres my other 2 week old baby. A grasshoper ate most of her stem. Now about a ince of her stem is eaten down to thin string like. But amazingly shes stil alive after 3 days. I repotted and buried the eaten part