To find out more about using a TDS meter to measure nutrients in your water, check out our article: PPM: What It Is and How To Track It.
In hydro, it is very helpful to get a tool called a TDS meter to help you regulate the amount of nutrients in your water. A TDS meter will be able to tell you how much “stuff” is in the water, and whether the levels of nutrients are getting higher or lower each time you check. You can test your reservoir at any time to see if the levels of nutrients are rising, so you’ll be able to stop nutrient burn before it even affects your plants.
Many nutrient systems come with instructions to feed your plant more nutrients than most plants actually need. It’s good business for the nutrient companies if you use more nutrients. However, in my experience it’s a good idea to view the feeding charts that come with any nutrient system as the maximum amount of nutrients and actually start with much lower levels. I tend to start with half the recommended amount, and slowly work my way up only if needed.
Luckily, there is an awesome tool to make this much easier in hydro.
In hydro, once you change the water and lower the nutrient levels to an appropriate level, you should immediately notice the nutrient burn stop spreading. Old leaves won’t recover, but you shouldn’t notice any leaves getting worse.
As nutrient burn progresses, the tips start getting bronze, crispy, curled and sometimes twisted. Although you can stop nutrient burn from getting worse, the burnt appearance won’t go away on the leaves that were already affected.
Each cannabis plant is different, so you might have just one out of many plants get nutrient burn! That is completely normal.
Sometimes you’ll also see nutrient burn leaf tips also curl or “claw”. The clawing can be caused by an overabundance of Nitrogen (Nitrogen Toxicity), which is common for plants that are experiencing nutrient burn from overall high levels of nutrients.
Learn more: Nitrogen Toxicity
(“The Claw”, tips bent down, curling / clawing, dark green leaves)
Nutrient burn causes the tips of cannabis leaves to turn yellow or brown. The burnt tips are the result of too-high levels of nutrients. Learn how to fix it!
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 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.
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.
One of the numerous benefits of growing in organic soil is that it provides a buffer zone of organisms around the root system. Soil grown plants are more resilient to overfeeding and other stressors. A well-prepared organic soil really needs no nutrients for the entire grow cycle, removing the danger of burning altogether.
- 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:
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.
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.
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?