Topping a plant during its flowering stage causes significant stress, which severely slows down its growth and drastically inhibits its final yield. It is a highly discouraged practice that can detrimentally affect the health and productivity of your plants.
Understanding Topping: A Vegetative Stage Technique
Topping is a high-stress training (HST) technique where the main stem or a primary branch tip is surgically removed. The primary goal of topping is to encourage the plant to grow bushier, rather than taller, by creating two new main stems from the node directly below the cut. This ultimately leads to a more even canopy and potentially more flowering sites, or "colas."
However, this technique is exclusively recommended for the vegetative growth stage. During this period, plants have abundant energy reserves and are focused on developing leaves and stems, allowing them to quickly recover from the stress of topping and redirect their growth hormones effectively. For more details on proper topping, you can consult reputable horticultural guides like those from Oregon State University Extension.
The Detrimental Impact of Topping During Flowering
When a plant enters the flowering stage, its physiological priorities shift dramatically. Energy is no longer primarily directed towards vegetative growth and recovery from stress; instead, it is focused on developing flowers and buds.
If you top a plant during flowering, several negative consequences can occur:
- Excessive Stress: The plant experiences a severe shock, diverting critical energy away from flower development towards healing the wound and recovering from the trauma. This can halt or significantly slow down the delicate process of bud formation.
- Slowed Growth: Instead of rapidly expanding its flowers, the plant must now spend precious resources on repairing the damaged meristematic tissue. This leads to a noticeable slowdown in overall plant development and flower maturation.
- Inhibited Yield: The most significant impact is on your harvest. Due to the diverted energy and prolonged stress, the plant's ability to produce robust, dense flowers is severely compromised. This results in smaller, less potent, and significantly reduced yields.
- Increased Vulnerability: A stressed plant is also more susceptible to pests, diseases, and environmental fluctuations, further jeopardizing its health and productivity.
Why Flowering is a Sensitive Period
During the flowering stage, plant hormones are finely tuned for reproduction. Any major disruption, like topping, throws these hormones out of balance. The plant interprets the damage as a threat, triggering a survival response that prioritizes repair over flower production. This can lead to:
- Stunted Flower Development: Buds may stop growing, remain small, or even attempt to "re-veg" (revert to vegetative growth), which is disastrous for the harvest.
- Reduced Resin Production: The quality and potency of the flowers can decrease as the plant's resources are redirected away from secondary metabolite production.
Safe Alternatives for Canopy Management During Flowering
While topping is off-limits during flowering, there are less stressful techniques you can use to manage your plant's canopy and optimize light exposure:
- 1. Low-Stress Training (LST):
- Gently bend and tie down branches to create an even canopy without cutting.
- This technique encourages side branches to grow upwards, promoting multiple main colas.
- It minimizes stress and can be continued into early flowering.
- 2. Strategic Defoliation:
- Carefully remove a limited number of large fan leaves that are blocking light from lower bud sites or hindering airflow.
- This should be done sparingly and avoid excessive removal, especially during peak flowering, as leaves are essential for photosynthesis. Focus on leaves not directly contributing to light capture.
- 3. Trellising or Scrogging (Screen of Green):
- Utilize a trellis net or screen to support branches and spread them horizontally.
- This ensures an even distribution of light to all potential flowering sites and prevents branches from collapsing under the weight of heavy buds. For more on these techniques, sources like Garden Myths offer insights into various gardening practices.
| Feature | Topping in Vegetative Stage | Topping in Flowering Stage |
|---|---|---|
| Purpose | Increase branches, bushier growth, more colas | No beneficial purpose; detrimental. |
| Stress Level | High, but plant recovers quickly | Extremely high; severe shock. |
| Growth Impact | Redirects energy for new growth | Slows or halts growth; energy diverted to recovery. |
| Yield Impact | Can increase yield with proper execution | Significantly reduces yield; inhibits flower development. |
| Recovery Time | Days to a week | Weeks, if at all; may never fully recover or produce viable yield. |
| Recommendation | Highly recommended for plant structure | Strongly discouraged; causes irreversible damage. |
Best Practice: Timing is Everything
For optimal results, ensure all high-stress training techniques, including topping, are completed several weeks before your plants transition into the flowering phase. This gives them ample time to recover, establish new growth points, and consolidate their energy stores for the demanding process of flower production. Always ensure your plants are healthy and robust before performing any HST. Remember, after topping, do not remove the leaves from that node as these are needed to power growth of the branches from that node. Do not top unhealthy plants at any stage.
In conclusion, avoid topping your plants once they have begun to flower to safeguard their health, growth, and ultimately, your harvest.
