Nutrient Burn In Cannabis Plants
Nutrient burn can affect cannabis during any stage of growth. Prevention, identification, and remediation are all essential pieces of knowledge in the cannabis grower’s arsenal.
Nutrient burn in cannabis could be called the “novices lament” or “over-enthusiasm backlash.” Nutrient burn is a type of stress caused by overfeeding your plants or mixing nutrients too strongly. Novice growers are often under the misconception that more is better. This is very untrue. Often, burning can be caused by simple human error. Luckily, the condition can be fixed before it demolishes your crop. That said, it can damage a crop at any stage of its development.
Unlike animals (humans included), plants don’t put on weight when you overfeed them. After all, plants are a whole different order of organism. They require a balanced and ongoing series of chemical reactions to survive and thrive. Trying to fatten them up with extra feeding is the fast track to disappointment.
Nutrient burn can be caused by:
- Mixing nutrients stronger than recommended during any phase of growth
- Overwatering; plants need a dry period to function properly and access oxygen
- Using bloom boosters too often or in too high a concentration
- Using growth stimulants too regularly, causing dwarfism and burning due to excessive nutrient uptake
Nitrogen is the predominant compound found in cannabis nutrients, especially during the vegetative phase. Nitrogen toxicity will be quickly followed by more severe symptoms.
Early indications of nutrient build-up prior to burning can be:
- Very deep green leaves
- Bright, Day-Glow green, almost fluorescent tips
- Leaf tips bent at 90°
- Stalks and branches will become deep red, magenta, or purple
- Sugar leaf and calyx tips will turn yellow, then dieback. Unlike the appropriate dieback of leaves during flowering, overfed bud leaves will remain engorged while they yellow, then dieback quickly and crisply
Further indications of nutrient burn are yellow, burnt tips on leaves. This will be widespread as over-fertilisation affects the whole plant. Small, burnt tips are common and nothing to worry about. When the yellowing intensifies and advances, however, it is time to take action. Once leaves start to curl and go brown, they are definitely goners.
Nutrient burn can be gradual if the overdose is only slightly stronger. It can also be rapid-appearing, progressing over a few days. The worst-case scenario is a chronic overdose that causes crop-wide yellowing and wilting overnight with leaf curl and lack of turgidity. In this case, if during the vegetative phase, start again. Recovery may be impossible or take longer than restarting completely.
Buds can be affected by nutrient burn as well. During the flowering phase, cannabis changes the way it uses nutrients. The need for nitrogen drops almost to zero while the demand for other compounds like calcium and magnesium increases. An overdose of any kind of additive will cause the same type of burning features.
HOW TO FIX IT
Once your plant’s woes have been identified as nutrient burn, carefully remove all the damaged material. Break off all the damaged leaves. Trace calyx clusters back to their branch and remove the whole florette, just to be sure. Dead flowers and leaves will rot. As soon as possible, flush your growing medium out with clean, pH balanced water. If you are growing with a reservoir, measure the contents with a pH/EC meter and adjust with fresh water.
If you are mixing daily by hand, then calm down tiger, less is more with cannabis. Keep in mind that satisfactory results can be obtained with just plain water for the whole life of the plant.
Prior to returning to a regular feeding schedule, use a specialised plant tonic to nurse the plant back to health. The root biosphere will have been affected, as well as the green parts of the plant. Tonics with silver nitrate, humic and fulvic acids, vitamins and minerals are ideal to restore plants to health.
When returning to regular feeding, use only ¾ strength to avoid burning again. Plants will quickly regain their vigour and continue to grow strongly. Remember to adjust the growing period to allow for time lost when the plants were ill. Adding time to the vegetation photoperiod will not harm the plants. If the burning happened during flowering or with autoflowering strains, then you will just have to take the lower yield on the chin.
Prevention is always the best policy, so it is a bright idea to develop good habits that decrease the chances of mistakes. First of all, be sure to use the correct nutrients for the appropriate growth stage. Even then, it is a wise idea to only use ¾ the recommended dosage on product packaging. Sometimes, manufacturer recommendations can run things a bit “hot,” which leaves little room for error.
Use an EC/pH meter to check nutrient strength every time, whether hand mixing daily or in hydro reservoirs. Be sure to flush hydroponic systems, grow mediums, and soils to prevent salt build-up in the root zone.
Over-enthusiasm with nutrients can burn marijuana plants. Knowledge is power when it comes to big buds. So, how to prevent and treat nutrient burn?
Is This Nutrient Burn on My Marijuana Plant?
Does your marijuana plant have brown edges, yellow tips, burnt tips, or similar symptoms? This is probably one of the most frustrating grow problems because it can be really hard to pin down the cause. Most pot growers are told they have “nute burn” or nutrient burn. That’s the cause some of the time, but often there’s another problem.
No more wondering! Learn whether you have nutrient burn on your plants, or something else!
Nutrient burn can burn the tips of your leaves, but other problems cause similar symptoms. How can you tell the difference?
Before you start reading this page, ask yourself the following questions:
- Do I have a good growing environment? (Not too hot/cold, gentle breeze, fresh air, etc.)
- Could I be overwatering (or underwatering) my plant?
- Did something different happen right before I starting seeing symptoms (cold night, heat wave, watered plants heavily, foliar spray, new supplement, etc.)?
Keep those answers in mind. Without further ado, here are pictures of common problems, so you can determine what’s causing your burnt tips.
This is Nutrient Burn
Nutrient burn (or “nute burn”) is the result of giving plants more nutrients than they need. The first sign is brown leaf tips. These burnt leaf tips are a sign the plant isn’t able to move water and nutrients properly in the plant. If the nutrients aren’t dialed back, the brown can spread inward from the leaf tips.
Nutrient burn caused brown, burnt tips that will crumble between your fingers.
Nutrient burn may also be accompanied by dark green leaves (the result of too much Nitrogen)
This is Overwatering
Overwatering your plants is common. It’s often a sign you love your plants and want to give it everything. But watering issues can cause a surprising number of symptoms that are often mistaken for something else.
Signs it may be overwatering:
- Plants are droopy some or all of the time
- May look like a nutrient deficiency
- Soil or coco appears dark, muddy, or has patches of green algae
- Top of grow medium never dries out between waterings
- Leaf symptoms often get worse the day after watering
This looks like a nutrient deficiency but the actual cause is overwatering. It’s extra easy to overwater small seedlings in a big container.
Chronic overwatering can cause the edges of leaves to turn brown
This looks a bit like nutrient burn or a nutrient deficiency, but these brown curled tips were caused by giving too much water, too often. New symptoms appeared after each watering. The leaves started growing green and healthy once the grower stopped soaking the soil.
Sometimes overwatering causes brown patches that look like a calcium deficiency. This is because overwatering disrupts the inner processes of the plant, which can trigger a wide variety of symptoms.
This is Light Stress
Even if it’s not hot, marijuana plants can still get stressed out by too much light (for example if the grow light is too close). Sometimes the leaf symptoms appear almost like a sun burn, with the leaves closest to the light appearing bleached. But sometimes the first sign is yellow leaf tips close to the light.
Signs it may be light stress:
- Leaf tips are yellow instead of brown
- Yellow tips appear close to the light (instead of all over the plant)
Light stress can cause yellow leaf tips close to the grow light
This is a more extreme example of light burn
This is a PH or Nutrient Problem
Nutrient deficiencies can also cause burnt or yellow leaf tips and edges. It’s possible for a plant to use up all the nutrients if growing in soil, but I’ve found that most marijuana growers provide nutrients in some form. If you’re still seeing nutrient deficiencies, the likely cause is incorrect pH at the roots. Boring, I know. But pH is the root of a lot of growing problems!
A potassium deficiency causes the edges of leaves to appear burned
Another example of a potassium deficiency
A potassium deficiency doesn’t affect tips as evenly as nutrient burn, and creates symptoms further into the leaf
A copper deficiency causes yellow edges and tips on dark leaves
A magnesium deficiency can also make leaf edges yellow or light green
Those symptoms looked different from each other, but they had the same cause: the grower didn’t check the pH of the water before giving it to their plants.
This is Heat Stress
Marijuana plants often start getting stressed out when it gets above 85°F (30°C). Some strains are even more sensitive depending on where they originated from. Learn 5 secrets heat control.
Heat Stress can make leaf edges look burnt
An extreme case of heat stress after experiencing 100°F (38°C) for several days
This is Bugs or Pests
Certain bugs and pests can cause burnt leaf tips or edges. For example, a heavy infestation of fungus gnats (which look like tiny flies buzzing around the soil) can damage the roots and cause symptoms that include brown or burnt leaf edges.
A bad bug infestation can cause a variety of symptoms (look what these fungus gnats did to this poor plant!)
Marijuana leaves with brown, burnt, or yellow tips can be hard to diagnose. Sooooo many problems can cause symptoms that look almost exactly the same. Once you identify the issue, it’s easy to fix. I hope this article helped you figure out the cause of your problem.
Does your marijuana plant have brown, yellow, or burnt leaf tips? Discover whether your brown tips are from nutrient burn or 5 other common causes.