Many issues can arise when growing weed: discoloration of leaves is usually a sign of nutrient deficiency; tiny spots or webbing can mean a bug infestation; stunted growth can be a root problem.
What’s wrong with my weed plant?
Cannabis plants are resilient. The plant grows successfully all over the globe in many different climates—it’s called “weed” for a reason.
Common mistakes when growing marijuana
Inspect under fan leaves, as that’s where some bugs live—such as spider mites—and check where the stalk comes out of the soil, as some bugs live there too—in particular, root aphids.
Spider mites, and most other pests, hide on the undersides of your fan leaves so always check that part of the plant as well.
One of the more common types of fungi you will encounter as a cannabis grower, white powdery mildew is often a result of too high a humidity in the grow room, coupled with low or no airflow. Eventually this powdery substance forms on your plants and continues to spread and make more mildew while eating up your cannabis plants.
(Read also: Growing Cannabis in Humid Conditions: Mold-Resistant Strains)
If you notice these signs on your plants, all you’ll need to do is water them more frequently and give them more per watering. If your leaves are drooping, give them a quick watering and within 30 minutes they will be standing right back up nice and perky!
When there is not enough potassium in the plants system, the leaves will begin to turn a bright yellow and will die. This is easily fixed by first checking to make sure you’re using the correct pH. If you are, then you’ll want to add a nutrient into the mix that is high in N.
Don’t freak out if something does start to happen to one of your plants, as it’s not the end! The best course of action is to view the signs and symptoms on your plant and then compare them to the symptoms listed below. Once you find the right match, continue your research and follow the instructions for how to cure it and within a few days you should see signs of recovery!
As soon as you spot this issue, raise your lights 6 inches to 1 foot higher. How close your lights should be is always determined by their strength and the stage the plants are in. Be sure to look at the manual your light came with as it will always explain the ideal distances for that specific light.
If in the wrong pH range, it can cause your plant to go into a nutrient lockout, which means it is essentially in shock and no longer absorbing nutrients for the time being.
In addition to the previously mentioned types of nutrient deficiencies, which can all occur during the flowering phase, several other types of nutrient deficiencies are common during the flowering phase. When a cannabis plant is flowering it requires more nutrients, which is why so many more types of nutrient deficiencies occur during this phase of the plant’s growth cycle.
Phosphorus deficiencies are fairly rare with cannabis plants, however, they do occur. When older leaves on the plant start to experience brown spotting, or another dark color, and growth has slowed and new leaves are really small, it’s likely due to a phosphorus deficiency. Remove the spotted leaves and boost feeding with a phosphorus-rich nutrient product (they are very common at gardening stores).
Potassium deficiencies are also common during the flowering phase. A flowering cannabis plant uses a lot of potassium since potassium is what helps the buds swell in size. A potassium deficiency shows itself via the yellowing and ‘burned’ look on the edges of the blades of leaves. Nutrients rich in potassium are easy to find at any gardening store.
It is nearly impossible to refrain from getting emotionally invested in a cannabis garden. That is also true regarding the financial investment. So when things go wrong in a garden, no matter the size of the operation, it can be soul crushing.
Common Nutrient Deficiencies During The Vegetative Stage
The fact of the matter is that the cannabis plant can be finicky with hurdles and issues popping up during the cultivation process. One very common problem is cannabis nutrient deficiencies. Marijuana plant deficiencies come in many forms, knowing how to spot them and how to fix them is crucial to success.
Combining certain nutrients and using them at the same time to feed plants can lead to nutrient uptake deficiencies in cannabis plants as well. Some nutrients effectively cancel each other out when mixed together, and that’s a common issue that arises when inexperienced cultivators make their own nutrient mixes.
However, just because a cannabis plant looks unhealthy does not necessarily mean that it is lacking proper nutrients. It is possible that the plant could be experiencing health woes due to something else such as a bug infestation or a temperature issue.
Common Nutrient Deficiencies During The Flowering Stage
When a cannabis plant is fed, the plant’s roots absorb nutrients from the moisture and grow medium, or in cases of hydroponics, the water that the roots are suspended in. In layman’s terms, the roots eat the nutrients and get them to where they need to go throughout the plant via a process known as nutrient uptake.
One of the most important things that every cannabis cultivator can do is a daily visual inspection. It is likely that many cannabis cultivators stare at their plants probably more than they should, however, many make the mistake of not inspecting their plants often enough. Whether it’s bugs, temperature, disease, some type of equipment malfunction, or nutrient deficiencies, it does not take long for a cannabis garden to be ruined, which is why constant monitoring and early intervention is key.