While there are many strains of weed that are naturally tall and get taller the longer they grow, there are some things you can do to help keep them from getting too tall. Cannabis plant growth height is dependent on the surrounding environment. You can make changes to the plants’ environments if you want to alter the seed-to-harvest times of your crop.
Plant Growth Height
The most significant factor in how tall a weed plant will grow is light. All plants naturally stretch to soak in as much light as possible to function properly. The light’s energy is used to convert chlorophyll and give the plant the energy it needs to produce leaves, stems, seeds, and buds. Now, some growers might think that the taller the plant, the better. But that’s not necessarily true. If your plant is stretching to reach light beyond its needs, the stalk and stems could be damaged. If the plant gets too close to the light, it could suffer from burnt leaves or damaged buds.
Temperature is another important factor in your plant’s growth height. The warmer your growing room is, the more the plants will stretch. However, if there is too much space between the internodes on the plant (length between stem and buds), your plant is not growing optimally.
Air circulation and quality are also essential to the perfect growth height. When you’re circulating air with an oscillating fan, the plant should be able to move in the wind but not be blown over. If the plant has stretched too far, it will become top-heavy and could fall over on itself.
Some growers practice “topping”, a technique where you pinch off newer growth at the top of the plant and give the lower stems and leaves a chance to catch up. This not only affects plant height, but lateral growth as well. Topping removes the tips that contain Auxins, hormones that are responsible for plant growth. By removing Auxin in strategic places, the plant will grow to your wishes.
If you’re starting from scratch with seeds, your cannabis plant will go through the four stages of growth: germinating, seedling, vegetative, and flowering. The time frames for each of these stages varies based on the strain of the weed, the growth process, and whether or not the plants are grown indoors.
The germination phase, which is typically 1 to 7 days, will give you a tap root you can use to grow a seedling. Sativa strains usually take longer, 4 to 7 days, while indica strains can give you a tap root in just a day. So, if you’re looking for a shorter seed to harvest time, start with an indica strain.
During the seedling phase, about 2 weeks, your plants can easily sit in a windowsill and get adequate light for 18-24 hours each day. Don’t think about transplanting the seedlings until they have a good, strong root system. This can be anywhere from 10 to 15 days, again, depending on the strain and the care you give the plants.
Once the plants have reached the vegetative stage, their growth speed will be determined by their environment: light, heat, humidity, and nutrients. The plants will require more than 18 hours of light exposure daily, a consistent temperature around 72 degrees F, humidity of no more than 50%, and a balance of nutrients (nitrogen, phosphorous, and potassium).
This period usually takes 2 to 8 weeks; however, you can manipulate the growth cycle by reducing the light exposure to 12 hours per day and decreasing the levels of nitrogen in the soil. This will lead to a faster flowering stage.
The final stage of growth, the flowering stage, is typically 6 to 12 weeks in length. The humidity should be lowered to between 40% and 50%, light exposure to 12 hours per day, temperature lowered to around 68 degrees F, and lower amounts of nitrogen in the nutrient base.
During an indoor weed grow, you ultimately control how tall your plants will get and how quickly or slowly you will go from seed to harvest. Light, heat, temperature, and nutrients will all be essential components of healthy weed growth.