How to Produce Cannabis Cuttings
1. Start with sterile water. This helps prevent diseases. The water should be around 68°F (20°C).
2. Choose a professional two-part nutrient. Add part A and stir, then part B and stir.
3. Stimulate root production. Add a root accelerant to the nutrient solution then stir again. This encourages strong and vigorous roots.
4. Check pH to ensure optimal nutrient availability. Use a calibrated digital pH meter to verify that the nutrient solution’s pH is between 5.5 and 7.0. If the pH is above 7.0, add diluted (not straight out of the bottle) pH Down, little by little until the pH falls within the correct range.
5. Prep pots then moisten. Line two- or three-inch net pots with net pot liners and fill with premium quality, pith-rich coco coir and place in a propagator tray. Alternatively, use large cell trays, coco propagation blocks, or stonewool cubes. Gently tap the pot or tray a few times to get rid of any large air gaps. Thoroughly moisten (flush) the propagation media with the nutrient solution. Discard any run-off.
Pro tip: To prevent diseases, ensure all hardware has been thoroughly pre-sterilized with bleach.
6. Take small cuttings. Select a healthy mother plant that is not flowering and has no visible diseases or pest infestations:
- Step 1. Select “lead” growth tips wherever possible. Ideal length is three to five inches with one leaf set (two leaves) at the base that can be removed later on (Fig a1). When these lower leaves are removed (see Step 2), this region offers greater rooting potential when placed into soil.
- Step 2. Work quickly with a sterile, sharp blade (razor blades are good but be careful). Remove lower set of leaves flush with stem, but without cutting into it. Then cut through the stem on a 45-degree angle about a quarter-inch (6 mm) below this (Fig a2). Do not tear or crush the stem.
- Step 3. Insert one inch of base of cutting (Fig a3) into a clone gel. Finally, insert stem about one inch deep into a pre-made hole (slightly undersized) in the centre of the pot or block (Fig a4). It should fit snugly. Be careful not to bruise or damage the stem.
Note: Steps 1 to 3 should be done quickly to minimize stresses on the cutting such as dehydration and air ingress.
7. Seal in moisture. Place propagator lid on tray and generally close any vents (Fig b). Relative humidity should be maintained about 90 per cent (open vents slightly if required). To combat any persistent wilting, spray two to three times per day with water or a clone spray. Avoid pools of liquid at the bottom of the propagator — propagation media should never be allowed to sit in water.
8. Place under low-intensity fluorescent light. Use 6,500K lamps and leave on for 24 hours a day. Monitor temperature inside the propagator using a thermometer with a remote probe. Aim for 75-80°F (24-27°C). Use a thermostatically controlled heat mat if temperatures are too cold (unlikely). Raise lights if too hot (more likely).
9. Check cuttings regularly. Once roots form (typically after five to 10 days), the propagation media can become dry very quickly, often catching growers out. Re-moisten using the same solution. In some cases, top-watering fails to water the entire propagation block. Full immersion of the block itself may be required.
10. Be patient and clean. Wait until roots have fully explored the propagation media before transplanting — keeping the cuttings moist (but not drenched) with regular top-ups of mild nutrient solution. Vents can be gradually opened once roots have formed. This will help prevent diseases. Also, maintain hygiene by keeping hard surfaces wiped clean, and remove any dead plant matter as this is an ideal host for fungi.