When should I stop training my plants?

Q: When should I stop training my plants?

Stop training cannabis by technique. Do the last topping at least 7–10 days before the flip to 12/12. Finish hard LST bending and supercropping by flower week 2–3, when stems lignify at the end of the stretch. Keep tucking under a net for about the first 2 weeks of stretch. After that, only gentle guiding and support.

Short answer

Stop each kind of training at its own point. Top for the last time at least 7–10 days before the flip. Finish hard LST bending and supercropping by flower week 2–3, when the stretch ends and stems stiffen. Keep tucking under a net for about the first 2 weeks of stretch, then only gentle guiding. Grower practice.

Why

Training builds an even canopy, and an even canopy puts more bud sites in good light. Yield follows light ^[2], and shaded lower buds carry lower, less uniform cannabinoids ^[1].

Topping is the slowest to recover from: 3–7 days before visible regrowth. Done in flower, that recovery comes out of bud-building time.

The stretch is the last chance to shape the plant. Stems and internodes elongate fastest roughly 5–10 days into short days ^[3], so most height gain happens in the first 2–3 weeks after the flip.

Remember the flip isn't day 1 of flower. The first 10–14 days after 12/12 are a transition, and that's exactly the window when bending and tucking still work.

By week 3 stems have lignified. Woody stems crease or snap when bent, and the plant is now spending its energy on flowers, not on regrowing.

The numbers

Technique	Last done	Notes
Topping, FIM	7–10+ days before the flip	Never in flower
Hard LST bending	Flower week 2–3	Gentle guiding after
Supercropping	First 2 weeks of flower	Green stems only
SCROG tucking	About the first 10–14 days of stretch	Then let tops grow up
Lollipopping	Flip to about day 21	Lower third only
Leaf tucking	Any time	Tuck, don't pluck
Support (stakes, trellis)	Any time	Heavy colas need it in late flower

What to do

Plan back from the flip date: last top 7–10 days earlier.
Keep LST ties moving every 2–4 days through veg and early stretch.
Tuck shoots under the net for the first 2 weeks after the flip.
Supercrop any runaway tops before week 3.
From week 3, only support, tuck leaves and adjust gently.

Common mistakes

Topping after the flip.
Starting hard bends in week 4 and snapping woody branches.
Forgetting ties as stems thicken in flower.
Stripping leaves instead of tucking them.

Full article: LST: low-stress training
Answers: recovery after topping · plant too tall for the tent · when to flip
Training: topping · supercropping
Terms: tucking

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.Supercropping is gently crushing a stem's inner tissue between the fingers and bending it over, so the branch lowers, toughens at a knuckle and stays productive.The stretch is the rapid increase in height in the first two to three weeks after switching to flower, when many cultivars grow 1.5 to 3 times taller.An even canopy is one where all main tops sit at roughly the same height, so each receives similar light intensity and buds develop more uniformly.A bud site is a node where flowers form, where leaf meets stem, or a branch tip; training aims to put more of them in strong light.A cannabinoid is any compound that binds the body's cannabinoid receptors or shares the typical cannabis terpenophenolic structure; the plant-made ones are phytocannabinoids such as THCA and CBDA.The length of stem between two adjacent nodes; short internodes mean compact plants and tight bud stacking, long ones mean stretch.12/12 is the classic flowering schedule for photoperiod cannabis: 12 hours of light and 12 hours of uninterrupted darkness, which triggers and sustains flowering.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.SCROG (screen of green) trains a few plants under a horizontal net, tucking shoots so the canopy forms a flat, evenly lit layer of many tops.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.Lollipopping removes the lower branches and small shoots on a plant, usually around the flip, so energy goes to the top buds and airflow improves underneath.A trellis is a net, mesh or frame that supports plants and spreads their branches, either as a SCROG screen or as support for heavy colas in flower.The dense, elongated cluster of flowers that forms at the end of a stem or branch; the main cola tops the leader.

Follow-up questions

Can I LST in flower?

Yes, you can keep LST going into early flower, but stop hard bending by mid-stretch, around flower week 2–3, when stems turn woody. During the stretch, tuck tops under a net or steer them gently instead of forcing sharp bends. Later, bending woody stems risks creasing or snapping; if one creases, tape it and it usually heals.

Can I top in flower?

Don't top in flower. The plant needs 3–7 days before visible regrowth after topping, and in flower that recovery comes straight out of bud-building time. Do the last top at least 7–10 days before switching to 12/12 so the new tops are growing strongly at the flip. If a plant is too tall in flower, supercrop or bend it instead.

Can I supercrop during the stretch?

Yes, supercropping works well in the first two weeks of flower, while stems are still green and the stretch is pushing tall tops toward the light. Pick a pliable section 5–15 cm below the tip, soften it gently and bend it over. After about week 3, stems are woody and more likely to snap, so switch to support stakes or a trellis.

Sources

Danziger N, Bernstein N, 2021. Shape matters: plant architecture affects chemical uniformity in large-size medical cannabis plants. Plants 10(9):1834. pmc.ncbi.nlm.nih.gov/articles/PMC8468686/

Rodriguez-Morrison V, Llewellyn D, Zheng Y, 2021. Cannabis yield, potency, and leaf photosynthesis respond differently to increasing light levels in an indoor environment. Frontiers in Plant Science 12:646020. doi.org/10.3389/fpls.2021.646020

Alter H, Sade Y, Sood A, et al. 2024. Inflorescence development in female cannabis plants is mediated by photoperiod and gibberellin. Horticulture Research 11(11):uhae245. doi.org/10.1093/hr/uhae245