Have you noticed the leaves on your plant turning a yellow or brownish color? Are they becoming dry and brittle? Perhaps some of the leaves have started to curl downward at the tips. If you have observed any of these symptoms, your plants are most likely suffering from nutrient burn or even a nutrient deficiency.
You would be hard pressed to find a grower who hasn’t had some experience with nutrient burn. In fact, whether you are a seasoned grower or just a beginner, it is a common mistake made during the growing process. Although most people would think that providing more food would result in a bigger, hardier plant, the truth is that feeding plants an excess of nutrients can actually be detrimental to the plant’s growth cycle and overall health.
Yet, even novice growers shouldn’t lose faith in their gardening skills when this common problem occurs. While the issue of overfeeding is generally caused by human error, your crops, plant, or garden can still be rescued if you can quickly identify the symptoms of over-fertilization and have a good understanding on how to fix nutrient burn before it gets out of control.
What is nutrient burn?
Nutrient burn is what happens when you overfeed a plant. When overfeeding occurs, your plant(s) will show physical signs of stress. Although excessive feeding will cause damage to the plant’s roots, the most obvious signs will appear on the leaves—as if the plant is trying to communicate they are in trouble.
All plants need light, air, water, and nutrients to grow. When plants receive the proper amount of mixed nutrients such as nitrogen, potassium, calcium, etc., they grow into healthy, thriving plants. However, when over-fertilization occurs, plants don’t have the ability to process more nutrients than they should. This is when they can become sick and damaged.
Although overfeeding a plant can damage the root system of a plant, the most obvious damage will be to its leaves. Brown and scorched leaves that suffer from nutrient burn no longer have the ability to absorb light. When this happens, the leaves can no longer contribute to photosynthesis; the process that keeps plants alive, thriving, and healthy.
How to identify nutrient burn
Generally speaking, plants that are affected by nutrient burn, might not show symptoms right away. That is why it is important for growers to be aware of the early signs of nutrient build-up. Catching it in time is possible if you can quickly determine what the problem is and adjust the nutrient balance—prior to the progression of the plant ‘burning.’
The discoloration of the leaves is a grower’s tell-tale sign that your plant is developing a problem. When a plant is given an excessive amount of nutrients it will try to rid itself of the surplus by moving the nutrients as far from the roots as it can. Subsequently, because the leaf tips are the most extended part of the plant, the tips will become the first part of the plant that will exhibit signs of overfeeding.
Early warning symptoms
- Slow plant growth
- An intense deep green coloration in the leaves
- Tips of the leaves bend or curl slightly downward
- A slight yellowing at the very tip of the leaves
Symptoms that need immediate attention
- Discoloration to the leaves; yellow or brownish color on the leaf tips
- Burnt leaf tips
- Wilting or twisting leaves
- Dry and falling leaves
Oftentimes, inexperienced growers will become overzealous and focus on the yield of their crop rather than the amount of nutrients they are providing to the plants. Many enthusiastic growers initially have a mindset that more is better. However, when it comes to mixing and applying a nutrient solution, successful growing requires knowledge of how to measure and administer the proper amount during the various growing stages of a plant’s life.
Common causes of nutrient burn
- Mixing a nutrient solution that is too strong or using more than the recommended dose.
- Feeding your plants too much—not following a schedule.
- Overwatering—limits the plant’s dry period required for proper functioning and oxygen intake.
- Extended drying period—soil that becomes dried out will alter the plant’s nutrient to water ratio; resulting in an increase of nutrients.
- Over-using phosphorus and potassium enriched bloom boosters or administering a too high a concentration.
- Using growth stimulants on a regular basis results in nutrient build-up that causes dwarfism and burning in plants.
It is important for growers to understand that maintaining the proper nutrient balance is critical to the plant’s health. A grower who tries to force growth by overfeeding will be left with not only an ‘out of whack’ system that will cripple the growing stages of a plant; but will inevitably require nutrient burn recovery.
Resolving Overfeeding Issues
The good news is that depending on how damaged your plant is, fixing nutrient burn might not be as difficult as you think. Here are four steps you can take to help your plants recover from nutrient burn:
Step 1- Cut your losses by cutting off any affected foliage (this includes any damaged buds) and remove any leaves that are dry or have fallen off to prevent rotting and potential mold.
Step 2- Flush out the medium and clean the roots.
- Hydroponic system—empty reservoirs and fill with fresh pH balanced water that is allow to run through the system for at least 24 hours
- Soil-based environment—-heavy irrigation with pH balanced water. Continually watering affected plants with proper run-off drainage will flush out the medium’s excess nutrients and clean the roots.
Step 3- Adjust your nutrient solution. Always refer to the manufacturer’s label on your liquid or powder container/bottle for the recommended measurement of nutrient solution and feeding schedule. Of course, the suggested ‘dosage’ may vary slightly based on the type of plant you are growing. In order to adjust your nutrient solution correctly, a TDS meter that determines the amount of dissolved particles in the water, usually in parts-per-million or ppm, should be used to measure the conductivity of the solution.
Step 4- Give your roots a boost. Root stimulators containing of vitamins, hormones, and microbes can accelerate the root growth. Giving roots a little jolt helps them develop faster and stronger so it’s easier for the plant to recover and return to normal.
Nutrient Burn vs Nutrient Deficiency
Consider a scenario where your plants appear visibly distressed. This is when your troubleshooting skills will really come in handy. Are the yellowish leaves and burnt tips a case of nutrient overfeeding? Or, are those lower curling, yellow leaves an indication that your plant is simply not getting enough nutrients to flourish?
Discerning the difference between nutrient burn and nutrient deficiency will be critical in addressing your plant’s problems. While many symptoms of overfeeding can easily be identified, the fact is these nutrient burn symptoms can be similar in plants that aren’t getting the proper amount of nutrients essential for growth.
Signs of nutrient deficiency
- Yellowing of the leaves during the vegetative stage- Nitrogen deficiency
- Stem and leaves that have a hint of purplish tint- Phosphorus deficiency
- Tips and edges of mature leaves have yellow or ‘burnt’ areas; stems are weak and break easily- Potassium deficiency
- New top leaves appear spotted or stunted- Calcium deficiency
- Bands of yellow on leaves- Zinc deficiency
- Mushy, brown roots, & droopy pale green or yellow leaves- Oxygen deficiency
The easiest way to deal with nutrient burn or deficiency is to prevent it from happening in the first place. Following the manufacturer’s recommendation for a proper nutrient solution mix along with the suggested feeding schedule is the best way to begin any gardening endeavor.
If you think your plant has been affected by over-fertilization, many growers find that measuring the electro-conductivity (EC) of one’s nutrient mixes with an EC meter can be extremely helpful for keeping all nutrient levels in check. Generally, you’ll want to keep the EC between 0.8-1.3 if you are growing vegetables and 0.8-1.7 for flowers.
It is important to note that various plants may react differently to the exact same nutrient mix; especially during the different growth stages. For those inexperienced growers concerned about overfeeding, if you start with about a ¼ less than the normal recommendation of nutrient mix, this will allow you some ‘wiggle room’ for error as you closely monitor your plants. Rule of thumb in avoiding nutrient burn, going light on your fertilization will result in optimal growth.
Nutrient burn is generally an avoidable mistake, but it can be easily remedied and corrected if caught early enough. The key for any grower who wants healthy plants/crops that thrive during all the growing stages (seedling, vegetative, budding, and flowering) is to constantly monitor the plant’s environment.
When you are aware of the symptoms that both nutrient burn and deficiency cause in plants, you’ll be able to easily troubleshoot the problem. The next step is making the necessary adjustments so you can begin nutrient burn recovery and nurse your plants back to optimal health.