What is Lollipopping? 

This method involves trimming away the lower half of the plant's foliage, leaving only the top 8 to 12 inches of the canopy. This approach helps concentrate the plant's energy and resources on the upper buds, promoting healthier and more robust growth in that area.

For detailed steps on how and when to Lollipop your plants, check out BudTrainer's "Lesson #5 How to Defoliate and Prune Your Plants for Maximum Yield"