As your cannabis plants grow, they will frequently need to be moved into larger containers as available root space becomes limited. While it may be tempting to simply start plants in a 10-gallon pot and skip up-potting altogether, this will lead to water waste issues, smaller plants, and lower yields. Instead, plants should be started in a container that holds ¼ gallon to 1 gallon of growth substrate and gradually moved up to a larger volume flowering container.
The reason for up-planting can be found in the roots of a plant. The roots can only grow to be the size of the vessel they are placed in, after which they twist around on themselves and form a root ball, preventing them from growing any further. Once the roots are no longer able to grow, plant growth slows/stops, as the root system is not able to support the nutrition requirements of the foliage above.
For best results, make sure that each 4’x4’ area in your flower room has enough substrate to provide the highest potential yield available by the plants. If growing in soil, you are looking for 50-75 gallons of soil substrate to accommodate large yields; if you’re growing hydroponically, you will need approximately 35 gallons of root space on each 4’x4’ area in your flower room.
To keep plants from becoming “root bound” – limited in growth through a lack of available space – plants should be up-potted through their life-cycle to keep the roots actively growing throughout. When doing so, it is important to break up the root ball slightly before placing it in the new pot (a gentle teasing is all it needs). This allows the roots to break out of their small pot cycle and expand to fill the new pot more quickly. Breaking up a root ball is a common gardening technique that seems to have been forgotten when it comes to growing cannabis.
If this step is skipped, the roots will continue to grow in a circle and won’t reach out into the new soil as quickly. Just because you put a plant in new dirt, doesn’t mean it knows it is in a new, larger pot.
Applying mycorrhizal fungi and beneficial bacteria at this stage is another good way to instigate healthy and fast root recovery and growth after transplant. Once the roots are loosened up a bit, apply myco solution or powder to the root ball and the substrate under the root ball.
In order to promote healthy growth of your cannabis plants, up-planting should happen multiple times. Plants should move from a 1-gallon (vegetative – nursery) pot up to a 3-gallon (vegetative – teen growth) pot and then to a 5-gallon (vegetative – high power growth) pot before finally being placed in a 10-gallon or 20-gallon (flowering) pot. Allow 5-10 days of continued veg growth following transplant to allow the roots to recover and reach out to the edges of the container prior to placing them in the flower room.
Up-potting before plants run out of root space encourages plant growth and will lead to larger, healthier plants. Don’t believe us? Test it for yourself. Grow one plant without up-planting, one without breaking up the root balls each time you up-plant and one following our technique. The results will prove themselves.