|2. Identifying nutrient burn|
3. Treating nutrient burn
4. Preventing nutrient burn
Have you noticed that the tips of your marijuana plants’ leaves are turning brown, dry, and curling up at the tips? If you’ve seen these symptoms, your cannabis plants may be suffering from nutrient burn. Nutrient burn happens to cannabis plants when a grower feeds them more nutrients than they can metabolize. Luckily, plants will recover from this if you act quickly. Check out our nutrient burn solutions below.
Cannabis Nutrient Burn – What Causes It?
Nutrient burn occurs when a grower feeds their cannabis plants too many nutrients – it’s therefore usually the result of human error. A grower may feed their plants a mix that’s too strong, let their soil dry out, or overuse bloom boosters or growth stimulators.
Nutrient Mixes That Are Too Strong
One of the most common causes of nutrient burn is when a grower feeds their plants a nutrient mix that’s “too hot.” This means that the total dissolved solids (TDS) of the mix is too high. You can check the TDS of your nutrient mixes with a PPM meter. An inexperienced grower may think that feeding their plants high levels of nutrients will make them grow bigger. However, this isn’t the case – in fact, quite the opposite. Often, nutrient burn occurs when a grower uses bottled, inorganic nutrients. Natural solutions such as bat guano, compost or worm castings are much easier on the soil and plants, yet just as effective.
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Letting Soil Dry Out
Plants absorb nutrients that are dissolved in water. However, if that water dries up, plants lose their ability to consume them. Instead, the nutrients crystalize around the plant’s root system. That, in turn, can cause the TDS of the plant’s soil to spike, which will result in nutrient burn. Because of this, it’s important to prevent your soil from becoming bone-dry by sticking to a regular watering schedule.
Overusing Bloom Boosters
This is another common error for newbie growers. Common sense dictates that pumping your plants full of bloom boosters should make them develop massive flowers, right? Unfortunately, it’s not that simple. Bloom boosters are rich in phosphorus and potassium – two nutrients that are crucial for plants in the flowering stage. However, these minerals both have extremely high TDS, and as a result, they can quickly cause plants to experience nutrient burn during flowering. Hence, you should always follow the directions on the package precisely so as not to overdo the boosters.
Overusing Growth Stimulators
Growth stimulators are similar to bloom boosters, except they’re intended for young, vegetative plants. Instead of being high in potassium and phosphorus, growth stimulators are rich in nitrogen. While younger plants are usually more robust than older ones, they can still succumb to over-feeding. Often, overusing growth stimulators can result in nitrogen toxicity, which will cause the leaves of your marijuana plants to turn dark green and curl down instead of up.
How Do I Identify Nutrient Burn?
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There are two main phases of nutrient burn, each of which have their own symptoms. As the problem develops, you’ll see several symptoms begin to arise that will indicate your plants are in distress. In addition, the symptoms of nutrient burn can be easily mistaken for other issues, resulting in a false diagnosis.
Nutrient Burn – Symptoms
Early signs of nutrient burn may not be obvious to inexperienced growers. First, the leaves of your plants will turn deep green except for the tips, which will appear bright yellow. The tips of the leaves of your marijuana plants will also curl up. As nutrient burn continues to develop in weed plants, the yellowed, curling leaves will begin to die and your buds will begin to turn yellow or brown.
False Positives – Similar Problems
There are several issues that may look like symptoms of marijuana nutrient burn but are actually indicative of a different problem. For example, light stress can cause leaves to begin to turn yellow at the tips. However, this will occur only on specific parts of the plant, while nutrient burn happens everywhere in the plant. Potassium deficiency and pH fluctuations can also cause leaves to turn yellow or brown, but with this issue, you won’t see your weed plant leaves curling up.
Treating Nutrient Burn
Understanding and identifying nutrient burn is just part of the solution – you also need to know how to fix it. Luckily, the road to nutrient burn recovery isn’t especially difficult. When cannabis is over-fertilized, you’ll need to do two things. First, you must remove any part of the plant that’s turned yellow or brown. These parts of the plant are just going to die and rot anyway. Then, you’ll need to pH a few gallons of water to between 5.5 and 6.5. After that, water your plant heavily. Saturate the media completely until water begins to flow from the bottom of the plant’s container. This is called “runoff.” Measure the TDS of your runoff with a PPM meter, and stop watering once it’s the same as your nutrient mix was going in.
Preventing Nutrient Burn
The easiest way to deal with cannabis over-fertilization is by preventing it from happening in the first place. One of the best ways to do that is by measuring the electroconductivity (EC) of your nutrient mixes with an EC meter. In general, you want to keep your EC between 0.8 and 1.3 for veg and 1.7 for flower.
Final Thoughts – Act Before It’s Too Late
Although over-fertilizing cannabis plants doesn’t have to be a huge problem, it can quickly snowball out of control. However, if you stay vigilant and water heavily at the first sign of nutrient burn, your plants should bounce back to full health within a relatively short time.