Transplanting and repotting cannabis is important for keeping your plants happy and healthy as they grow. When repotting and transplanting is carried out at the right time in the right way, it promotes abundant root growth and plant health, which contributes to overall growth rate, structural stability, maturation and yield.
On the other hand, when these actions are carried out at the wrong time or in an improper manner, plants can be damaged — even fatally injured.
When To Transplant Cannabis Plants
Your first consideration must be when to transplant. Transplanting of clones needs to happen when cuttings have a healthy number of roots emanating from the initial media they were planted in, which is usually root shooters, Grodan Grow-Cubes or blocks, or peat pots. In a garden where ideal cloning conditions are present, cuttings will be ready for transplanting within 7–15 days after they’ve been taken from the mother plant.
The first transplanting of seedlings takes place when sufficient root growth is visible in the initial media in which the seeds were planted. This is generally within 8–20 days after the seeds have germinated.
Check out the below YouTube clip from Jorge Cervantes about transporting plants into a Smart Pot:
Cannabis Transplanting Methods & Destinations
Transplanting methodology and materials are influenced by what clones are rooted in or in what medium seedlings are germinated. For example, some growers might use aeroponics cloners and intend to grow their plants to maturity in pure hydroponics systems, such as deep water culture and aeroponics.
In this case, the cutting and its root puck are transferred to the net bucket and collar assembly often found in pure hydroponics systems. The bulk of the plants’ roots as they grow will hang in open space, feeding on water, oxygen and nutrients. The grower has only to make sure roots aren’t dehydrated, bent, or broken during transplanting.
In fact, transplanting pure hydroponics cuttings from their origin point to their deep water culture or aeroponics system is the easiest and cleanest transplanting a grower could wish for.
Transplanting and repotting with solid root-zone media can be easy or difficult, depending on what you’re growing in. Rockwool transplanting isn’t messy, for instance, and can be almost as easy and clean as pure hydroponics transplanting.
Rockwool transplanting involves starting your seeds or cuttings in small rockwool cubes, transplanting those cubes into larger rockwool cubes, and then putting the larger cubes into a flood and drain, ebb and flow, or slab system.
My most successful cannabis gardens have been those grown in rockwool in which the transplanting process can take seconds, no mess or fuss. It’s just a matter of picking up the rockwool block and putting it in a new location.
Transplanting a cutting or seedling into soil, soilless mix or coco coir involves taking the cutting or seedling, hollowing out a space for it in the location you’re transplanting it into, planting it so it’s level with the media line, and then watering it in with a low-PPM nutrients solution containing B-52 stress-reducing formula, Voodoo Juice, Tarantula, and Piranha beneficial microbes and base nutrients.
How To Time Your Cannabis Transplanting & Repotting
When it comes to the cannabis transplanting game, timing is a crucial consideration. If the plants are destined for a sea of green setting, they’ll only be transplanted once, they’re almost certain to be clones, and most likely will be growing in raised tables or closely spaced rockwool systems, rather than in individual pots.
On the other hand, if plants are in Solo containers and are to be full-size photoperiod plants rather than sea of green or autoflowering marijuana plants, there will be at least two transplants.
The first transplant takes place when the young clones or seedlings have sufficient roots showing. The second transplant happens in mid-to-late grow phase. There could be a third transplant, but only if the plant is showing signs of being root bound (more on that in a moment).
The second and any subsequent transplantings in soil, soilless mix or coco coir will likely be the messiest and has the most likelihood of going wrong, due to the removal of your plant from its existing container.
If a grower has transplanted a rooted clone or seedling into a one-gallon container and then wants to transplant it into a five-gallon or seven-gallon container to carry it to harvest, especially if the grower is using rigid plastic pots, it can be difficult to dislodge the plant from its small pot. One thing you don’t want to do is yank the plant’s stalk from above to try to wrench it out. This will almost always damage the root structure, which can stunt the plant and reduce its bud production.
Here are some key pointers to remember whenever you’re transplanting in such a situation:
- Be gentle with root balls.
- Don’t let direct sunlight hit plants.
- Get plants into their new container immediately, and don’t grab plants and roughly pull on them to get them out of their container.
Check out the below short YouTube clip courtesy of Drunkenblaster about how to best transplant your cannabis:
Smart Pots For Easier Cannabis Transplanting & Repotting
My favorite repotting and transplanting regimen utilizes a cloth pot Smart Pot program. These are pots made of durable cloth, with each increase in pot capacity accompanied by an increase in pot height and diameter, so it’s easy to fit the entire existing root ball into the new larger container.
Instead of pushing the root ball through the container or rolling the container on the floor to loosen the root ball so I can ease it out of the smaller pot, I take a razor knife, cut the cloth pot vertically in four or five top-to-bottom slits, peel the cloth pot sections away from the root ball, put my hand underneath the base of the root ball, and lift it away.
Instead of slicing the pots open and peeling them away in this manner, some growers attempt to peel down the Smart Pot’s sides without slicing, but I’ve found this method doesn’t always work.
I measure the height of the root ball and compare it to the height of the container it’s headed for. This gives me an indication of how many inches of soil I should put into bottom of the destination container so that after transplanting, the top of the root ball is just slightly below the top of the destination container.
After I’ve placed several inches of solid root-zone material in the bottom of the new container, I drop the container from a couple of inches to settle the material. Then, I sprinkle a thin layer of Bonide Bontone Rooting Powder on the media. While many people believe that rooting powder is only useful for cloning, it’s also useful for promoting transplant root growth.
If the root ball is root bound, now’s the time for root pruning. Being careful to support the root ball so that little if any solid media falls away from the roots, and being careful to ensure the root ball sits evenly, I place the root ball in its larger container and gently fill in material from the sides. Every 2–3 inches, I distribute powdered rooting hormone around the sides, then continue filling.
After the container is full to near the brim, I again pick it up and smack it on the floor a few times to settle the medium. You’ll notice the medium will lose several inches of height as it settles, so pack root-zone material firmly in the edges of the pots, making sure there are no creases in the sides where pockets of empty space exist. If you don’t pack your material firmly, the media will collapse from the top when you do your watering, leaving air gaps that are likely to harm roots.
Don’t pack your pots so full that the root zone is exactly flush or above the top of the pot. If you do, water will run out onto the ground when you irrigate.
Once repotting is finished, water your plants with a three-quarter-strength hydroponics base nutrients formula as appropriate for the stage of growth your plants are in, beneficial microbes root boosters Voodoo Juice, Tarantula and Piranha, along with B-52 and Rhino Skin.
Thoroughly soak the expanded root zone until you see water running out of the sides and bottom of your cloth pots.
After watering, watch for places where the root-zone material has settled. You often have to add material to the top of the root zone to keep an even level, and sometimes to cover stabilizer roots that are exposed after the transplant; these should be slightly covered with your medium.
Repotting and transplanting are essential cannabis grower skills. When you’re growing full-sized photoperiod plants from seeds or clones, plan ahead of time for at least two transplants, so your cannabis roots always have room to expand in their container.