Topping removes the apical meristem, the main growing tip, by cutting through the stem just above a node. This breaks apical dominance: the two side shoots at that node become co-dominant tops. Repeating the cut on each new top doubles the count each time (2, 4, 8).
In practice
Most growers top a photoperiod plant once it has 4-6 nodes, cutting above the 3rd to 5th node, and let it recover for about 5-7 days before the next cut. Topping lowers height, widens the plant and creates a flatter canopy, especially combined with low-stress training. Each cut costs a few days of veg.
Myth check
House position for autoflowers: topping will never produce what proper LST or training does. An auto runs on a fixed countdown, so every recovery pause is lost time. If you top an auto at all, do it once, early and on a vigorous plant; LST is the better tool. See topping and LST.
Don't confuse with
- FIM: a partial pinch of the tip that can give three or four tops; less precise.
- Top (slang): "top shelf", unrelated.
The zone of dividing cells at the very tip of a shoot (or root) that produces new leaves, nodes and stem; removing it is what topping does.The suppression of side-shoot growth by the main growing tip, driven mainly by auxin flowing down the stem from the apex.Codominance is when both alleles at a locus show in a heterozygous plant, as with THCA and CBDA synthase, so a B_T/B_D plant makes both THC and CBD.Top shelf is the highest price tier of flower in a shop, used as slang for any premium-looking cannabis; it reflects pricing and appearance, not verified quality.The daily length of light versus dark; photoperiod cannabis flowers when nights grow long enough, rather than at a fixed age.LST (low-stress training) bends and ties stems so the plant grows wide and flat, exposing more bud sites to light without cutting or breaking tissue.A day-neutral cannabis plant that starts flowering by age, usually a few weeks after germination, regardless of light schedule; the trait is mainly recessive.FIM is a training cut that pinches off most, but not all, of a plant's newest growing tip, often producing three or four new main shoots instead of one.Mainlining is a training method that tops a plant low, removes lower growth and splits it symmetrically into a set number of evenly sized main colas.The point on a stem where a leaf (petiole) and its axillary bud attach; branches, flowers and clone roots all originate at nodes.
