Topping a type of pruning that takes place just before the plants enter the flowering phase. Get some pruning shears and top all the branches to rein in the stretch that takes place during the flowering phase. This might sound drastic but will encourage the plants to focus their energies on producing flower heads rather than wasting energy on growing upwards.
The table below shows which seeds you need based on your needs.
These are two main strains of cannabis, although there are many hybrids which combine genetics from both. There are many visual differences between Sativa’s and Indica’s, and one of the most obvious is height. Sativa’s can grow extremely tall, to twenty feet and is slower to grow and reach harvest. Indica’s are compact, bushy plants that typically reach heights of between three and six feet. Hybrids vary enormously; we recommend reading information about the strain before your purchase to find out whether Sativa or Indica is dominant when it comes to potential growth. The other strain of cannabis is Ruderalis, whose genetics are often found in autoflowers, and this is also a short plant similar in size and shape to Indica.
Cannabis propensity to grow means that its height needs to be carefully controlled by you, the grower, without affecting the health of the plants and the quality of the yield.
LST is an easy and inexpensive method of training that simply involves bending the growing stems in the direction you want them to grow and gently tieing them in place. LST enables light to reach more buds by creating a more even canopy.
SCROG works similarly to LST but involves a screen, net or trellis against which the cannabis plant is encouraged to grow horizontally. This method also creates more budding sites by stretching out branches to expose more nodes to the light.
The average height of a weed plant is 1.25 meters (49 inches). How tall a weed plant gets depends on the specie, type of strain (photoperiod or autoflower) and growing conditions.
Get 2 x 40W 'daylight' CFLs (can support 1-4 seedlings)
Get 1-2 CFL bulbs and keep 2-3 inches away from the tops of your seedlings (be careful not to let seedlings grow into the light!)
To increase the amount of light, you either need to get stronger grow lights (what grow lights work for growing cannabis?), or move your current grow light closer to your plants.
Some growers bury the extra stem to make seedlings short again, which works, but as long as you start giving your seedling light it will do a "push up" and rise back up, strengthening its stem in the process! Here's what to do right away…
Answer: When marijuana seedlings are growing tall and thin like that, it means they need more light.
Question: Why are my young marijuana seedlings getting tall and dying? They're growing all stretchy with long stems, and aren't making new sets of leaves.
These cannabis seedlings are growing tall and thin (and falling down) because they need more light.