What is Cloning?
Cloning is a way of propagating plants through asexual reproduction of the plant by cutting and rooting a healthy shoot. This creates clones. It is also known as ‘taking a cutting’.
A clone has only one parent and is an exact genetic copy of that parent. This can happen naturally to many types of plants in the wild through a variety of processes, for example, when a strawberry plant lays down runners the resulting baby strawberry plants are clones of the original. Because of this natural ability the cloning of plants is separate from the controversy and ethical debate that surrounds the cloning of animals.
If you can not get a clone of a plant you admire and want to grow then the very next best thing is getting the right genetics by buy a brand name seed from breeders. They have been keeping the strain steady and offer a pure strain to grow just as you would from a clone.
Cloning, over many thousands of years humans have exploited this ability to select plants that have particular desirable properties like high yields or pleasant flavors. Marijuana farmers are no different. The donor plant is often referred to as a ‘mother plant’. Your cloned marijuana is generally taken from a mother plant while in its vegetative stage. While they may be taken from your plant while flowering, the clone itself must revert to the ‘vegging’ stage and the hormonal shift required will slow down growth as the plant gets ‘confusing’ signals.
Why Clone Cannabis?
- When you have a high yielding, good tasting, or particularly potent individual plant you can replicate it.
- It is possible to ensure the gender of your plants. They are genetically identical to the mother, i.e. choose female;
- You can produce large quantities of new, individual plants;
- You can save money on seeds;
With a well designed grow room program you can be self sufficient for cuttings, growing only the highest quality weed from cuttings that you have selected yourself. Although all new smoke will taste the same as the last (given the same nutes); as it is genetically identical.
How to take a weed cutting
The first step in cloning your plants is to take a cutting. Although it is possible to take a cutting from a flowering plant we would advise against it. Once your plants are flowering leave them to do their thing – that is, growing top quality weed for you.
Choose a healthy plant with at least 6 nodes or 4 weeks old as the donor
Take cuttings from young pre-flowering plants. Once you have selected the phenotype that you desire, and are assured of its sex, keep it growing under 18-20 hours light to prevent it from entering the flowering cycle. This will be your mother plant and with good care she will provide you with an almost limitless supply of cuttings.
Some growers like to take cuttings from all of their plants (before flowering) as a matter of routine, especially if growing a batch of plants from seed. These cuttings are clearly labelled to correspond with the parent plants. Then, when the parent plants are finished it is possible to select the best one and choose the relevant clone. Now your next batch of young plants will be exact copies of your favorite adult.
- To take a cutting you will need a clean, sharp razor blade, scalpel or sharp scissors. Sterilize the cutting edge with rubbing alcohol
- Make a cut at a 45 degree angle, i.e. on the 45. Select a green branch quite low on the plant with 2 or 3 nodes, (not a fan leaf. Avoid woody branches. Using the razor cut the branch at a diagonal angle about ¼ inch (5-10mm) below a node.
Rooting your cutting
Your marijuana cutting requires four things in order to root:
- Low light to stimulate rooting. As the clone will not be adding leaf mass or performing significant photosynthesis, more is not better. The light basically triggers certain hormones
- A support structure
- Moisture around the roots
- High humidity to keep the leaves from drying out.
The simplest way for a single clone is to put your cutting in several inches of water in a Dixie cup and cover with a plastic baggie to retain moisture. Change the water every 3 days. Marijuana clones will root in roughly 6 to 14 days. Just prior to the appearance of the roots, white bumps will be visible on the lower part of the stem submerged in water (if that is the method you are using). Some gardeners transplant when the roots are 1” long while others wait until they are 6” long. Personally we like to wait until they are at least 3” long. Longer roots take more time, but generally results in less shock when transplanted.
Rooting marijuana with a gel or powder
Although it is possible to root cuttings in water it is recommended that you use a rooting gel or powder. Remove the bottom leaves from the cutting and dip it in the rooting compound, then plant the cutting in your desired growing medium. Rockwool cubes work particularly well.
At this stage the cutting is very fragile. Do not force it into the growing medium. Make a hole with a pencil and gently place the cutting into the hole, closing the hole around it with your finger tips.
If you take the cutting from just above a node on the plant, then that branch will split into two as if you had pinched it out. This way your mother plant will produce an exponential number of cuttings and keep you happily supplied with babies for your nursery.
Once all your cuttings are ready and in their pots, give them a drink of water and a mist from a water sprayer. Ensure that no light can reach the roots. If you have several cuttings put them into a propagation tray with a plastic lid, this will help limit the effects of transpiration and ensure that the plant holds onto plenty of water. Remember at this stage the young clone has no roots so must absorb water through the leaves and cut stem.
The young plants will need light, but in this fragile state it is important not to burn them with hot lights. Start with a fluorescent light or full spectrum LED grow lights at about 10 inches (25cm) away and gradually move it closer as the plant develops. If you don’t have space for a separate nursery area place the young plants in the grow room, partially shaded by the leaves of the mother.
Caring for Cannabis clones
Over the next couple of weeks your new plants should develop their own root system. Remove the propagator lid and fan the plants every day to ensure adequate ventilation. It is worth making a few holes in the lid to help with this. It is also important not to overwater these young plants. Roots need oxygen to grow so make sure that they get proper drainage. Feed the plants on just water for the first few days and then begin giving them a very diluted nutrient mix. After about two weeks, when you can see the plants’ root systems becoming strong, the plants can be re-potted into larger containers and take their place in your growing system.
Once you have learnt the basics of cannabis cultivation the next step is to get yourself a mother plant and start cloning.
The first is economy; quality cannabis seeds are not cheap and unless you are cultivating marijuana for seed production you will want to avoid having to lay out big bucks on new seeds every time you start a grow.
The second reason for using clones is that they speed up the start of the cannabis growing process. They avoid the need for germinating seeds and the time it takes waiting for them to become established.
The third main reason for cloning your cannabis plants is to do with quality. Some of the best strains of cannabis have varying phenotypes and when you find yourself with a great phenotype that has all the qualities that you desire, it only makes sense to repeat this by cloning the plant to produce genetically identical offspring.
The trouble with this process is that it is not until your plant has flowered that you can tell her true qualities, and this is obviously too late to turn her into a mother plant without having to revert her to the vegetative stage, which can stress the plant. So here is what you do.
How to select a mother plant
When you receive your new batch of seeds [start them off as you usually would]. Once they have established themselves and are growing well, take cuttings from each plant. This will normally be during the third or fourth week of vegetative growth. It is important to take cuttings before the appearance of pre-flowers. Clones have the same biological age as their donors so cuttings taken from a flowering plant will continue to flower even if they are only a few inches tall. Taking clones from plants during their vegetative stage allows you more control over the outcome.
Clearly label the cuttings to correspond with each donor plant. You can keep the cuttings in the same room as the donors under 18 hours light, or whatever lighting regime you prefer.
Once your clones have become established you can separate them from the donors and begin to flower the donors by changing the lighting to 12/12 as usual. Remember to keep the cuttings on their vegetative light cycle.
As soon as any males appear you should remove them immediately, as usual, and remove the corresponding clones. These will no longer be of any use to you.
If you are using a strain of cannabis that has a particularly long flowering period, like some of the [Hazes] for example, the clones may become too big to be manageable and will want to start flowering. If this is the case, simply take clones from the clones and continue to veg these second generation clones.
Keeping a marijuana mother
Now you have your mother plant. She is still in her early stages. If you have had to take more than one generation of clones whilst waiting for flowering, make sure that your chosen mother has had at least three weeks of veg before taking cuttings from her.
Remember, if you are running a larger operation that needs a high volume of clones, simply take several clones from the selected mother and grow these on to make multiple moms. They will all be genetically identical. However, one mother plant is normally sufficient for most personal grows.
Once you are sure that the mother is well rooted and into full vegetative growth you should pot her up. Many growers like to put the mother in a large pot and let her veg into a bush, providing many cuttings whenever they are required. This is an effective system, but it requires space. It is possible to create ‘Bonsai’ mothers that will provide you with a couple of dozen cuttings every two to three weeks, depending on your own individual lighting and feeding set ups.
Root trimming a cannabis mother plant
Root trimming your mother plant is simple. Slip the plant out of its pot. The root ball will be an almost solid, square sided mat of tangled roots. Remove the loose compost from the top of the ball. Take a sharp clean knife and cut between a half inch and an inch from each side and from the bottom. Place some new clean potting compost in the bottom of the pot. Repot your plant back into the pot and pack out the sides with some new soil. Water and feed her well and she will bounce back in no time.
How long can I keep my mother plant?
How long is a piece of string? Technically it is possible to keep a cannabis mother plant forever, if you continue to provide her with the correct lighting and nutrients. There are lots of stories of mother plants that are still producing after 20 years or more.
[Updated, originally published 6.11. 2017]
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