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Marijuana (Cannabis)

Transplanting Hydroponic Marijuana Plants

You can transplant hydroponic plants and cannabis plants grown in soil. Transplanting will cause stress to the plant and growth will slow down dramatically or stop, until the plant recovers.

Full recovery will usually take 3-5 days, sometimes longer, so it is best not to transplant any plant. But sometimes there is no avoiding it.

When there are two or more different grow areas, a plant might need to be moved to a different room and into another hydroponic system or growing container.

In other cases plants started in a hydroponic cloner will have to be moved to a larger hydroponic system, or in some cases into soil.

Hydroponic Media
Step By Step
List Of Materials
After Transplanting


To transplant a hydroponic plant into a new growing container and solid hydroponic media like rockwool, the first thing to do is set up the hydroponic system the plants will be moved to.

Add water and nutrients, check nutrient strength and the pH level. Plug in lights, timers, pumps, any other items. Make sure they and everything else operate properly before attempting to transplant.

Have your work area and the items you will need ready. Sterilize scissors, growing containers, work surface, your hands, anything else the roots will contact with hydrogen peroxide or rubbing alcohol and a clean cloth or paper towels.

If the hydroponic system the plants are being moved into has a high water level (like dwc, ebb&flow, etcetera) put the grow cups in that system and if necessary run the nutrient solution pump.

Make note of the high water level in the grow cup. The high water level should submerge at least the bottom 1-2 inches/2.5-5.0 cm of the hydroponic media that the transplants will be put in, so the media and roots stay moist at all times.

With new plants like clones and seedlings, the high water mark should come into contact with the roots. With any hydroponic plant, the stem should never get to the point where it is submerged.

If it is not possible to get high water to come into contact with the roots of clones and seedlings, the media the plants are in should get wet enough to keep the roots in contact with moisture at all times.

Solid Hydroponic Media

Prepare the hydroponic media for the transplants. Rockwool has to be soaked in pH adjusted water prior to plants growing in it.

Other mediums will have to be prepared in some way, like being soaked in nutrient solution from the system it will be put in. Refer to the directions for your particular medium to be sure.

To reduce chances of shock, any medium you work with should be at room temperature when it comes into contact with plant roots.

For transplanting into solid hydroponic mediums, get the type that have a hole in the center where starter plugs can fit into.

Some rockwool and sure to grow products have starter plug holes. Other brands of solid hydroponic mediums should have similar products.

Sure To Grow Hydroponic Media And 3 Inch Net Pots

The media these particular plants are being transplanted into is sure to grow hydroponic inserts. They come in different sizes to fit in different size net pots.

These inserts are made to fit comfortably into 3 inch round net pots, also called net cups. The media has a diameter of about 3.25 inches/8.25 cm and is about 2.75 inches/7.00 cm tall.

Sure To Grow Starter Plug Cutout After Being Removed

With sure to grow, the place where starter plugs can be fit into has been cut on all sides.

It needs to be pulled out to provide room for starter plugs because it is still attached at the bottom.

After the starter plug cutout had been removed, the sure to grow inserts were then soaked in nutrient solution.

The nutrient solution was taken from the hydroponic system the transplants will be put into. This is in order to prepare the media for the transplants.

Subsequent to being soaked in nutrient solution, excess water was allowed to drain off into the hydroponic system. This was so they leaked a minimum of water on the work tray, but they were still wet.

Transplanting A Hydroponic Plant
Into Solid Hydroponic Media

The plants that are being transplanted in the images on this page are from a small homemade hydroponic system for germinating, seedlings, clones. The media the plants were started in was oasis cubes.

Hydroponic Marijuana Plants That Will Be Transplanted

The plants have matured to a point where they had put down a solid root system, several sets of leaves, were about 6 inches/15 cm tall.

They are being transferred from a small hydro system in a small grow area to a larger hydroponic system in a bigger grow area, to finish the vegetative stage. Then they will be cloned and flowered.

Have the media the plants are being transplanted into ready, take one or more of the plants out of the hydroponic system it is growing in, and bring it to your work area.

If the plant was grown in a hydroponic system with other plants and the roots have become entwined, you will have to cut the roots to free the plant.

Grow Cups Are Cut From The Upper Portion Of Water Bottles

If the roots have to be cut in order to free the plant, cut them so they are as long as possible.

If it is necessary the roots will be trimmed to a shorter length when they are moved into new media.

The grow cups these plants were started in are cut from the upper portion of water bottles. When transplanting, the stem of the plant just has to be pulled up and the roots won't be disturbed.

With plants that are started in net pots, the roots have to be cut or the net pot has to be left in place and transplanted into the new media.

Roots That Aren't Too Bulky Can Be Transplanted Without Being Cut

If the roots aren't too bulky, they can be inserted into the starter plug hole without being cut.

With the plant pictured here, the net pot was slowly turned as the roots were being lowered into the starter plug hole.

Make sure the roots are below the plant and don't stick up over the top of the media. If the plant can fit in and sit on top of them, you'll be ok.

Roots That Interfere With Transplanting Have To Be Cut Before Inserting In Starter Plug Holes

Sometimes roots will interfere with the transplant and have to be cut.

Make sure the roots will be long enough to come into contact with the media below them, when performing the cuts.

After the transplant is inserted in the media, you can hold it in place with one hand while you fill the gaps around the roots with small pieces of media that were cut from a larger piece of media.

Fill The Gaps Around Roots With Small Pieces Of Media

In this case, small pieces of media to fill in the gaps were cut from the starter plug cutouts removed from the sure to grow hydroponic media they were transplanted into.

Don't compress the media when you place it to fill in the gaps, it is just for temporary support until the roots anchor themselves. Solid hydroponic media has to spongy so it will hold nutrients, oxygen, water.

Root Guard Placed On Top Of Rockwool Block Cover

After the transplanting was finished, rockwool block covers that measure 4.5 x 4.5 inches or 11.4 x 11.4 cm were placed over the top of the 3 inch net pots.

Then 5 inch/12.7 cm root guards were placed on top of the rockwool block covers. The rockwool block covers and root guards stop light from getting to the roots, media, nutrient solution. As well, they help retain moisture.

The 5 inch/12.7 cm root guards were intentionally larger than those intended for 3 inch net pots because the grower finds the larger sized root guards do a better job.

Transplant In A New Larger Hydroponic System

When the work was finished, transplants were then placed in their new larger home which has a stronger light source.

After transplanting, the light was turned off so the plants could start the recovery process in darkness.

The day after transplanting when the light came on for the next light cycle, starting at the same time as it did previously, the transplants looked like this.

You will know the transplants are doing well when they have started to grow new leaves and you can see the new root system forming.

Progression Of Root Growth 3 Days After Transplanting

If the transplants were in the late seedling, vegetative, or flowering stage, the new root system will start to emerge from the media the transplants were moved into within a few days.

Plants that have just started growing and are in germination, clone, or seedling stages might take a week or more for new root growth to emerge from whatever medium they are moved into.

Prior to being transplanted, the plants shown in the images on this page had been getting 64 watts of fluorescent light for 18 hours a day. Following transplanting, the amount of light will be increased to 250 watts of metal halide for 18 hours a day.

After about a week under the 250 watt metal halide, the transplants done while working on this page will look like this and be ready to clone. Some of the lower branches, that won't get much light, will also be removed.

Three days or so later, when they have recovered from cloning and removal of branches, the plants will be forced to flower by changing the light cycle to 12/12.

Besides solid media like sure to grow or rockwool, hydroponic clones, seedlings, plants can be transplanted into a loose medium like soil or soilless mixes.

Partially fill the growing container with your media, construct a hole that is large enough to accommodate the roots of the seed, clone, seedling, or plant.

With one hand holding it in the position you want it to be in, use your other hand to gently fill around the roots with the media until the plant is solidly emplaced.

Don't compact the media around the plant too tightly, just enough so it's in contact with the roots and supports the plant.

Step By Step

A) Set up hydroponic system plants will be moved to.
B) Have your work area and items needed ready.
C) Sterilize anything the roots will contact.
D) Prepare the hydroponic media for the transplants.
E) Take transplants out of hydroponic system.
F) Bring transplants to your work area.
G) Some roots can be inserted without cutting.
H) Roots that interfere with transplanting are cut.
I) Fill gaps around roots with media.
J) If applicable, cover the top of growing containers.
K) Place transplants into new hydroponic system.

List Of Materials
sharp scissors
mildly lit work area
paper towel or clean cloth
hydrogen peroxide or rubbing alcohol
optional plant cover
optional root guards and block covers

*** tray: A tray that can retain water is a good idea for a work surface. Wet media will release some water when being worked on.

A boot tray made out of plastic, with a lip around the edge, will ensure that any water or nutrient solution will be contained where it can be discarded after you finish.

They come in various sizes, so take into consideration how big of a tray you will need to work comfortably. Don't use a dirty boot tray, work with something clean that will only be used for working on plants.

*** media: The media the transplants on this page were put into was sure to grow arroyo. They are about 3.25 inches/8.25 cm in diameter and 2.75 inches/7.00 cm tall, they fit comfortably into 3 inch round net pots.

Items sold as 3 inch round net pots have an opening that measures 3.25 to 3.75 inches/8.26 to 9.53 cm in diameter on top and 2.75 to 3.00 inches/7.00 to 7.62 cm in diameter on the bottom.

These transplants will stay in the same 3 inch net pots and hydroponic media from this point through vegetative and flowering stages until they are harvested.

Rockwool has products designed to fit in various size net pots and growing containers called gro blocks. Both rockwool and sure to grow have worked equally well for transplanting into when growing cannabis.

Solid media that has holes for starter plugs has to be the right size for the media going into it. The media the plants pictured in the transplanting photos on this page were started in was oasis rootcubes.

They were cut down to about 1 inch/2.5 cm cubes to fit in the grow cups, from larger oasis rootcubes. Oasis rootcubes are very easy to cut down to any size you want with a sharp utility knife.

The sure to grow arroyo had a starter plug hole that is 1.5 inches/3.8 cm by 1.5 inches/3.8 cm. The depth of the hole can be adjusted to about 2.25 inches/5.72 cm, by removing material.

Keep the starter plug cutouts after pulling them out. They might be needed to fill in gaps around the roots after putting the transplant in.

You should squeeze sure to grow inserts at the bottom while pulling out the cutout for starter plugs, the squeezing will limit the depth.

If you pull out too much or make a hole in the bottom, cut off a small piece from the cutout you removed and place it where required.

*** sharp scissors: Sharp scissors might be needed to cut roots and perform other similar cutting operations. If you have to cut the roots, do so with one clean cut from a very sharp pair of scissors.

*** mildly lit work area: A mildly lit work area is preferred over strong lighting. Roots don't require light. The light reaching them should be kept to a minimum. You have to be able to see clearly though.

*** paper towel or clean cloth: Paper towel or clean cloth soaked with hydrogen peroxide or rubbing alcohol can be used for sterilizing items.

*** hydrogen peroxide or rubbing alcohol: Hydrogen peroxide or rubbing alcohol are good for sterilizing items.

*** optional plant cover: A plant cover can be employed to maintain a high humidity level after transplanting. Be sure to get the right size cover for your needs.

*** optional root guards and block covers: Root guard lids and rockwool block covers come in various sizes and can be employed to cover growing containers when necessary.

After Transplanting

After transplanting, try to replicate the same nutrient strength the plants were getting before they were transplanted.

The nutrient strength can be decreased for the first week after transplanting but should not be increased. When the plants have recovered you can increase the nutrients.

For clones and seedlings that are less than 2 weeks old, 60 watts or more of fluorescent lighting is suitable.

For plants that are more than a few weeks old and have already established a solid root system and several sets of leaves, more light is needed.

Assuming more established plants were getting mild light before being transplanted (like fluorescent) for the quickest recovery time and growth rates, 250-400 watts of metal halide light should be provided after transplanting.

A move from mild fluorescent light before transplanting to 600 watts or more, of metal halide after transplanting, would be too drastic. You can increase the light to 600 watts or more after the plant has recovered.

If metal halide is not available, high output fluorescent lights can be substituted. The important thing is stronger lighting for older established plants after transplanting.

Another good way to help plants recover is to provide a fairly humid environment for a week or more after transplanting. 60% relative humidity or higher.

Foliar feeding will help keep plants from drying out. Simply dilute some of the nutrient solution in the hydroponic system and put it in a spray bottle.

Spray the leaves of the transplants with diluted nutrient solution and keep them moist. The nutrient in the spray bottle should be diluted so it is 10%-25% of strength of the nutrients being supplied to the roots.


1 --- Roots don't like light. When working on them try to keep light levels to a minimum. You need enough like to see clearly, but not much more.

2 --- After transplanting turn off the light and let the plant start to recover from transplanting while it sleeps. Start the light at the same time that the light turned on prior to transplanting. If you are increasing the period the light will be on, add it to the end of the day.

3 --- Plants started in an aeroponic cloner, or hydroponic cloner that doesn't use media, can be transplanted into solid media when the roots are about 1-2 inches/2.5-5.0 cm long. Hold the clone where you want it in the starter plug hole, while you fill in around it with small pieces of media.

4 --- For clones and seedlings under 2 weeks old, fluorescent lighting is adequate after transplanting. If the plants have already started growing leaves, providing 250-400 watts of metal halide after transplanting is highly recommended.

5 --- Plants adapt to transplanting better during germination, seedling, vegetative stages. Transplanting hydroponic marijuana plants during flowering is possible, but should be avoided unless absolutely necessary.

6 --- If you transplant during veg, wait until the plant recovers before initiating flowering by shortening the light period to 12/12.

7 --- Metal halide is preferable to high pressure sodium until the height of the plant slows down or stops increasing, several weeks after it has started flowering. High pressure sodium will cause plants to grow taller and more straggly if introduced too early.

8 --- A 3 inch net pot is large enough to support a large hydroponic marijuana plant. Increasing the size of the net pot will not result in a bigger plant.

The net pot is just hold the plant in position and so the roots can anchor themselves. It is the size of the container that roots are growing in that can limit the size of a plant.

In order to allow enough room for the roots to grow, a small hydroponic marijuana plant needs a 1 gallon grow pot. That is, the roots should have room that is at least equal to the area occupied by 1 gallon of water.

A 2-5 gallon grow pot is needed for large plants, like when only one or two plants at a time are grown. Otherwise the roots will not have enough room, and at some point they will signal the plant to stop growing, see this..

Related Books

Grow Great Marijuana
Very good choice for simple and accurate instructions about growing hydroponic marijuana. Does not cover advanced techniques, but if you have no experience, this is the first book to look at.
Grow Great Marijuana

The Cannabis Encyclopedia
Easy to read with comprehensive focus on growing and consuming for medical and recreational purposes. This will be of interest to growers, patients, caregivers, consumers, or anyone interested in consuming, growing, or producing cannabis products.

Over 2,000 color images on 596 pages. Loaded with recent information covering all aspects of marijuana. The grow section explains hydroponics and soil growing, growing indoors, outdoors, and in greenhouses.
The Cannabis Encyclopedia

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