Most growers start cultivating marijuana as a labor of love. The experience is rewarding but comes with its fair share of challenges. One of these is a molybdenum deficiency in cannabis plants.
In many cases, cultivators only notice they have a problem when the symptoms show. So how do you prevent it?
If your plants look a bit unhealthy and the colors lack vibrancy, they may need molybdenum (Mo). Below we explain the importance of the nutrient, the symptoms of a deficiency, and how to resolve it.
Let’s kick things off by discovering what role molybdenum plays in the well-being of weed plants.
What does molybdenum do for cannabis plants?
A molybdenum deficiency in weed crops can damage their overall health because they rely on the nutrient for its role in two enzyme systems. These convert nitrate into ammonium and make it easier for plants to synthesize amino acids.
The nutrient affects how the plant uses nitrogen, one of the macronutrients for marijuana cultivation. It also affects how micronutrients get absorbed.
One way to ensure healthy plants is by providing extra supplements. When you buy nutrients for weed, consider what soil they’re using.
High-quality varieties typically contain everything your plants need to flourish, whereas cheaper options need more supplementation. A molybdenum deficiency is more likely with the latter.
Although Mo plays a vital role, only a small amount is required. It’s easy to mistake a shortage of molybdenum for a nitrogen deficiency, but there are slight differences in symptoms.
What are the reasons for a molybdenum deficiency in marijuana?
There are several reasons for nutrient deficiencies in pot plants. In most cases, the cause is environmental factors or problems with the substrate. Some common reasons are:
Too much iron in the soil
While you have to take care to avoid an iron deficiency, having an excess of the nutrient isn’t good either. For optimal cannabis cultivation, aim to balance each factor.
When the pH levels are low, there’s typically more iron in the soil. The acidic conditions usually mean that there’s not enough molybdenum available.
Too cold temperature
The ideal temp for cannabis growth varies from strain to strain, but the typical range is 65–85℉. Certain hardier options can withstand cooler environments and display bright hues of pink or purple on the leaves.
On the other hand, many cultivars don’t do well in the cold. The lower temperatures reduce the availability of nutrients, and a molybdenum deficiency in cannabis crops could occur.
Unbalanced pH
The pH levels of your soil need to be optimal for successful marijuana cultivation. Having a substrate that’s too acidic or alkaline can lead to various issues such as:
- Calcium deficiency
- Magnesium deficiency
- Mo deficiency
As a preventative measure, test your pH level. A substrate that’s too acidic can result in a molybdenum deficiency. Aim for a range of 6–6.5 in soil and 5.5–5.9 in hydroponics or coco coir.
Identifying a molybdenum deficiency
A shortage of Mo in your weed crops isn’t easy to identify during the early stages. As the problem intensifies, symptoms get clearer. Common ones include:
- Reddish leaves with dark-brown spots or purple hues
- Leaves begin to curl upward
- Stunted growth
- Compromised leaf structure
These signs also signal a shortage of nitrogen. To distinguish between that and a molybdenum deficiency, look at the location of the symptoms.
If the discoloration starts in the middle of the plant and continues upward, it’s the latter. A nitrogen deficiency begins at the plant’s base.
In most cases, the leaves turn yellow and curl upward, but sometimes the color turns pink or red with brown spots. The leaf edges lose their vibrancy first, and the pale shade then spreads to the rest of the plant.
The leaf texture also changes. The leaves feel dry as they curl up, and if you don’t take action swiftly, they dehydrate, wilt and fall off.
Observe the height of your plants. When there’s a molybdenum deficiency in the weed crops, development slows, and they don’t mature as they should. These plants can’t use the nutrients optimally and therefore have stunted growth.
How to fix a molybdenum deficiency in cannabis
Mo mainly works in the crop’s roots. Different treatments work better for each stage of the problem.
One of the ways to fix a molybdenum deficiency is by ensuring the ideal pH levels. Flushing cannabis plants is the easiest method. Use plain water to wash away the current nutrients in the soil. Alternatively, add a small number of diluted supplements.
Provide thrice as much water as the size of your containers. If you have five-gallon pots, use 15 gallons to flush. Get rid of the runoff water quickly and ventilate the grow area so the soil can dry quicker. The extra fluid can cause additional issues if not removed quickly.
Once the soil is flushed, check the pH levels. If needed, add some pH up/down to get them back to where they should be.
If you know how to prune weed plants, use this method as a molybdenum deficiency in cannabis solution. Trimming the foliage has multiple benefits, such as improved airflow and light exposure.
It also helps direct the nutrients to where they’re needed most. So cut off any damaged leaves. As your plants heal, implement a feeding schedule to avoid similar issues recurring.
Depending on how soon you treat the issue, it takes a couple of weeks for your crops to recover. As the damage is already done, your final yield might also be less than you initially thought.
Managing molybdenum
A molybdenum deficiency in cannabis plants is quite rare, but it’s helpful to know how to handle it if it happens. The micronutrient plays an essential role in the health of marijuana crops, impacting the harvest.
To minimize your risk take preventative measures by keeping your pH levels and growing environment optimal. Observe the crops regularly for any symptoms of discoloration, stunted growth, or miss-shapen leaves, and begin treatment immediately.
Now that you know how to handle a molybdenum deficiency, why not start a cannabis crop? Browse our i49 seed store to find the perfect strain for your cultivation journey.
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