INTRODUCTION TO CANNABIS CLONING
Cloning is a technique where a part of a plant is cut and then treated in a way that encourages roots to form at the base of the cut.
The cut can then be used to grow an exact replica of the plant it was cut from.
Genetically, the cutting as the clones is called, is identical to the plant it was cut from.
There are many benefits of this procedure depending on the application of the grower. It could be to have more plants of the same type, it could be to preserve genetic lines after their source stock was flowered out and no more.
WHY IS IT USEFUL TO CLONE CANNABIS
So you just got your hands on some cannabis seeds that you really had an interest in but the pack has only a handful of seeds.
When you flower them out without cloning them you will not be able to grow that exact phenotype of that cannabis strain again. If you have interest in long term preservation of those cannabis genetics, then to grow that exact flower again, you need to take clones.
CANNABIS CLONING TECHNIQUES
The most common way to take clones of any kind of plant is to use either coir discs or rock wool cubes. Aerocloning has also become popular in modern times.
With all these techniques, the common part is to take the cutting in a consistent manner and the differences then begin depending on which method you use and how you use a rooting agent.
With coir discs and rockwool you would use a rooting compound applied to the base of the cut.
However with an aerocloner you would add a root stimulant into the reservoir.
HOW TO TAKE A CANNABIS CLONE
The cutting is best taken from plants in vegetative stage with growing tips. However a flowering top can also be cloned and put back into vegetative stage using the same methods described.
Use a clean cutting blade and cut a branch approximately 4 to 5 inches in length for best results. Make the cut at an angle, it doesn't have to be precise but many people suggest 45 degrees.
Remove any leaves and corresponding petioles from near the base to ensure that the lowest 1.5 to 2 inches of the cutting is free of leaves as this will be the part that develops roots.
Once leaves are removed, you scan gently scrape the stem around the base as this will help with root formation regardless of the type of rooting medium you use.
USING THE CORRECT ROOTING COMPOUND FOR YOUR CANNABIS CLONING METHOD
If you use using coir discs or rockwool then its quite straightforward - you can use any off the shelf rooting gel or powder.
In general they all have the same ingredients in different concentrations depending on the exact brand you can buy. Some popular brands are Clonex, Rootex and EziRoot.
If you are using a aerocloner then you need a liquid based cloning product. There are different products in different countries but what you are looking for is the same active ingredients as the powder or gel versions.
Those ingredients are:
Indole-3-butyric acid
1-Naphthaleneacetic acid
Some products will have one of them, some will have both.
The method of cannabis cloning you select will determine which type of compound you need to use.
APPLYING THE ROOTING COMPOUND TO CANNABIS CLONES
If you are using coir discs or rockwool cubes then you dip the base of the cut in the rooting compound insuring an even application to the lower 1.5 to 2 inches of the stem are coated in the rooting compound. You can then go ahead and plant this into a coir disc or a rockwool cube.
If you are using an aerocloner then you will need to measure the amount of freshwater that went in your reservoir and apply the cloning compound at the rate recommended by the manufacturer for that volume of fresh water. You will need to change this solution periodically, optimally once a week.
WHAT LIGHT DO I USE FOR CANNABIS CLONES
It best to use weak lights for clones because you don't want too much photosysthesis, you want root development.
You can use fluoro tubes or led strips or bulbs. They should be of low wattage.
The spectrum is the important part and should be around 6500K.
HOW LONG DO THEY TAKE TO ROOT
People will tell you legendary stories of roots in 5 days or similar but in reality most cannabis strains take up to 21 days to show good root development after cloning.
DO I NEED A HUMIDITY DOME FOR MY CANNABIS CLONES
Yes. A dome is needed preferably one with adjustable vents.
Around 14 days you can start opening the vents gradually and have them fully open at 21 days to help the clones acclimatize with ambient air outside the dome.
Between 21 and 28 days, is when you can safely move clones out of the humidity dome and into whichever environment you intend to progress them in.
CONCLUSION
These techniques are well known and have been used by growers all over the globe.