6 Top Cannabis Rooting Mistakes That Growers Make
Perfecting the propagation of cannabis cuttings can be tricky. Even seasoned growers make mistakes that can hinder the rooting process and overall plant health. In this article, we’ll explore common mistakes in cannabis rooting and how to avoid them for a successful crop.
1. Watering Too Early
The Mistake:
Cannabis cuttings are highly sensitive to overwatering. Applying the first irrigation too early can delay root formation and compromise the yield and quality of your plants.
How to Avoid It:
To determine the right time for the first irrigation, weigh your trays or individual cubes after initial saturation and after placing the cuttings. Regularly weigh the trays every few days and record the weights. When you notice initial callus formation and root development, take note of the tray’s weight. Pre-soak your medium that the cuttings will be placed in before you add the cuttings. Then wait till the medium dries out some before adding more water. The cutting need to have some stress from lack of moisture in order to promote more root growth from your cuttings. Add too much water at the start can “spoil” the cuttings with moisture making it so they do now need to grow roots as fast or at all as there is plenty of moisture in the cutting’s medium.
Optimal Conditions:
Depending on light intensity, temperature, humidity, and leaf area of the cuttings, you should aim for a dry-back to 50% or less of the full saturation weight within 5 to 7 days. Some cultivars may require more than ten days to achieve proper dry-back. Regular measurement and recording will help you determine the best conditions for each variety.
| Condition | Optimal Range |
|---|---|
| Light Intensity | Moderate to high |
| Temperature | 70-75°F (21-24°C) |
| Humidity | 70-80% |
| Dry-back Period | 5-7 days (may vary by cultivar) |
2. Overwatering
The Mistake:
Some rooting medium has a high water-holding capacity, which can lead to overwatering. Excess water pushes air out of the substrate, slowing root development and making cuttings more susceptible to diseases.
How to Avoid It:
For the first irrigation after dry-back, ensure the water only touches the bottom of the cubes or reaches a quarter of an inch up the side if using a flood or dip method. If top watering, a gentle spray is sufficient. Never leave water sitting in the bottom of your rooting trays. This can lead to bacteria growing in this warm pools of water and rot your new cuttings in one to two days. Make sure to drain all water from the bottom of the trays after each watering.
Tips:
Separate cuttings with visible roots from those without to avoid overwatering the unrooted cuttings. Measure the tray or cube before and after irrigation to find the best saturation level for each variety. Place the newly rooted cuttings into a new tray and feed and water as needed.
3. Using Too Low Nutrient Concentration in Soak Solution
The Mistake:
Stone wool is inert and doesn’t come with nutrients. Some growers mistakenly believe that cuttings without roots don’t need nutrients, leading to weak and nutrient-deficient plants.
How to Avoid It:
Include nutrients in your soak solution. Even without roots, cuttings need nutrients to maintain turgor pressure and stay alive. You can use simple rooting nutrients or even a very weak flowering nutrient to pre-soak your cannabis rooting medium in before adding your cuttings. Mixing a small bit of honey also can really help your cuttings get a very healthy start.
Optimal Nutrient Concentration:
Through trials, it’s found that an EC of 1.5-2.0 is ideal for soaking stone wool for cuttings, other types of mediums may have different EC ranges so you may be best to contact the maker of the product. Experiment with different concentrations to find the best for your specific cutting cultivar and environmental conditions.
4. Removing Too Much Leaf Material
The Mistake:
Cutting off too much leaf material to slow transpiration or fit more cuttings per tray can lead to inconsistent rooting and lower plant quality.
How to Avoid It:
Leaves act as solar panels and batteries, storing nutrients and water. According to a study by Caplan (2018), removing leaf tips can reduce rooting success from 71% to 53%. Leave a few extra leaves more then you think to keep the plants rooting more efficiently.
Tips:
Keep more leaves on the cuttings and maintain proper density, humidity, and dry-back. Cuttings with more leaves will need more frequent watering, so monitor them closely.
5. Overcrowding Cuttings in a Tray
The Mistake:
Overcrowding cuttings can prevent light from reaching all cuttings and create conditions for foliar diseases due to overlapping leaves.
How to Avoid It:
Give each cutting enough space to receive full light without touching its neighbors. Avoid cuttings touching the dome’s edge if using domes, as they can grow differently and be more susceptible to disease.
Spacing Tips:
If you have the luxury of space, try checker-boarding to avoid overcrowding.
6. Taking Cuttings from Old Mothers
The Mistake:
Older mother plants are more likely to harbor stress, pests, and diseases, which can affect the success of your cuttings.
How to Avoid It:
Ideally, use mother plants that are no more than 3 to 4 months old. Measure the success rates of cuttings from your mother plants and replace them when success rates decrease. Older mother plants also have more “woody” stems that will take longer to grow roots if at all. Sometimes these “woody” stems can take up to weeks extra to get roots. They also may require a stronger rooting compound to get them to root over newer cutting stems from a younger cannabis plant.
Advanced Method:
Some growers adopt the method of cloning mothers to destruction. Take the first batch of cuttings from young mother plants for the strongest cuttings, then replace the mother plants after each batch to ensure peak health and quality.
Summary List of Common Rooting Mistakes
- Watering Too Early: Delays root formation.
- Overwatering: Slows root development, increases disease susceptibility.
- Low Nutrient Concentration: Leads to weak, nutrient-deficient plants.
- Removing Too Much Leaf Material: Reduces rooting success.
- Overcrowding Cuttings: Prevents light access, promotes disease.
- Using Old Mothers: Increases risk of stress, pests, and diseases.
By understanding and avoiding these common mistakes, you can improve the success rate of your cannabis cuttings and ensure a healthier, more productive crop. Regular monitoring, proper irrigation techniques, and optimal nutrient management are key to achieving the best results in cannabis propagation.
