The general rule to follow is to cut your plant above the 5th leaf node in order to make sure that it's sturdy enough to deal with the stress. You'll also want to wait until your plants are at least 30 days old. This also leaves you with a decent amount of lower branches that can now grow outwards.
Here are some tips for topping marijuana plants:
Make sure to cut just above a pair of leaves, as this will encourage the growth of multiple branches. Know when to top weed plants; it can be done any time after the plant has reached the vegetative stage, but it's typically done when the plant is between 3-5 weeks old.
If you top them too early, you risk stunting their growth. Consider your light: If you're growing in an indoor grow space, and light leaks are a problem, consider topping your plants early. There are a few different ways to tackle light leaks, but topping is the most reliable solution.
Non-topped plants tend to develop one strong central stem that grows much taller than the rest of the plant, and becomes laden with flowers during the bloom stage. This dense region of flowers is called a “cola”. Meanwhile, the lower branches of the plant develop lighter foliage and fewer, often smaller flowers.
How do topping and training benefit plants? Topping's main benefit is increased lateral growth that sets your plants up for higher yields. Fueled by redirected growth hormones, lateral branches rush to catch up with vertical growth.
The side branches will end up filling out a bit more so it won't be a huge loss but all topping should be done during the vegetative stage and preferably not within two weeks or so of the plant starting the flowering stage.
Since topping is a high-stress training method, it's important to let the plant recover for a couple of weeks before doing any further cutting or pruning. But once the plant has stabilized and the new stalks are established, the topping process can be repeated over and over, potentially producing enormous yields.
Your plants need to be healthy before topping so they can heal from the trauma associated with this particular training technique. It is recommended that you wait until your plants have at least four nodes before topping them, and most growers recommend topping the plant above the sixth node.
You can harvest your plant by either cutting the entire plant down at once, cutting the stems down one by one while keeping the buds attached to them, or by removing the individual buds from your plant.
Whether you grow indoors or outdoors topping your cannabis plants helps to produce a bigger and better yield, which is every grower's primary goal. The first thing to understand is that topping is an exact cut at the node, and while that sounds easy, the timing of topping is critical.
Considering this, the majority of growers will tell you to wait 1–2 weeks between the end of topping and the beginning of flowering. A decent amount of growers, however, believe a plant can handle the transition with only 5–7 days of recovery.
Topping Too Early or Incorrectly
The first rule of topping is that it is best to wait until the main stem has at least 3 or 4 nodes as topping the plant too early can slow or even stunt the growth of the plant. When the plant is topped at the right size, it often won't slow down at all!
Some say that it is best to top the plant at night when most of the hormones have been sent to the roots. This means that there is a smaller chance of the plant being stunted after the main shoot has been removed.
A bud hardener is an additive you can use at the end of the flower cycle to tighten up your flowers and pack on weight. They are typically used in the final 3 weeks or so of the grow cycle and contain a mix of macronutrients, micronutrients, minerals, essential oils, etc.
If you wait too long, your buds will be overripe and possibly ruined. If you harvest too early, the buds may not have finished growing (and developing their potency). Ultimately, the goal is to harvest when your plants' trichome and resin production is at its peak.
Nighttime provides darkness, keeping cannabis on somewhat of a natural clock. This is why indoor growers need to make a deliberate effort to not only create long, bright days but also emulate dark cycles for cannabis to grow large full buds.
Only top before flowering
Even better is waiting 1 week, and then making the switch. If you have an autoflower, make sure to only top it if it flowers in 4+ weeks, or it will not have time to recover.
Plant leaf nodes are small bumps or swelling where new leaves or stems emerge from a plant. These are the sites where new growth occurs. Knowing how to identify them, will easily enable you to Propagate Your Plants , and also help you with other tricks, such as helping your plant branch.
Pre Flowering Stage. Most Cannabis plants will become developmentally mature when they reach 14”-20” in height, or 8 to 10 nodes of growth.
Topped vs Non-Topped Plants Produce Different Yields
On the one hand, topping encourages bushier lower growth and the development of multiple colas. However, it also exerts a large amount of stress on young cannabis plants, resulting in slower, stunted growth for at least seven days post-topping.
Topping your plant will halt its upward growth and allow it to spread laterally. As you change the light cycle to induce the flowering stage, the plant will put a lot of its energy into the growth of the flowers you are aiming for.
Healthy cannabis plants usually take two to three days to recover from topping. After topping, do not remove the leaves from that node as these are needed to power growth of the branches from that node. Never top during flowering as it causes too much stress, which slows growth and inhibits yield.
Week 2. In week 2 of flowering, you may spot the first white pistils growing on your female cannabis plants. These fine and wispy white hairs will develop at those locations where the big fan leaves meet the main stem. It is these fine hairs that will later become buds.