Pay attention that growing marijuana may be subject to special restrictions and regulation in your country or state. Please contact your attorney to obtain advice before cultivating cannabis.
Pay attention that growing marijuana may be subject to special restrictions and regulation in your country or state. Please contact your attorney to obtain advice before cultivating cannabis.
No matter how well you take care of your cannabis plants, they could get slow or turn yellow at any time. To stop a plant from turning yellow or to cure one that has already done so, you need to be able to figure out what caused it and how to fix it.
Seeing vibrant green cannabis leaves fade to yellow is worrisome for any grower. While some yellowing is normal as plants mature and flower, excessive yellow leaves can indicate bigger issues needing attention
By understanding the most common causes of yellow pot leaves you can diagnose problems early and take action to nurture your plants back to health. In this article, we’ll explore the top reasons marijuana leaves turn yellow and how to fix them.
Common Reasons Cannabis Leaves Turn Yellow
A variety of factors can cause pot leaves to become discolored and yellow. Here are some of the most likely culprits:
Underwatering – Dry soil leads to drought stress, nutrient deficiencies, and yellowing Leaves often appear wilted and thin as well
Overwatering – Saturated soil suffocates roots, causing leaves to yellow from lack of oxygen. Leaves may also look swollen or droopy.
Nutrient deficiencies – Lack of key nutrients like nitrogen, magnesium, and iron prevents chlorophyll production. Deficiencies cause uniform yellowing.
pH imbalance – Incorrect soil pH prevents plants from absorbing nutrients efficiently. Leaves yellow from deficiencies.
Lighting issues – Too much or too little light disrupts photosynthesis. Upper or lower leaves yellow accordingly.
Temperature stress – Heat and cold shock damage chloroplasts needed to keep leaves green.
Pests/diseases – Fungal, bacterial, or pest attacks damage leaf cells and tissue, impeding photosynthesis.
Genetics – Some strains and varieties are prone to leaf yellowing, especially during flowering.
Diagnosing the specific cause is key to getting your pot plants back to their vibrant glory.
Solutions for Yellow Leaves on Cannabis Plants
Once you’ve identified what is causing the yellowing leaves, you can take targeted action to remedy the issue:
Adjust watering – Allow soil to dry out between waterings. Improve drainage if needed. Prioritize bottom-watering.
Amend soil – Mix in compost or nutrients like worm castings to enrich soil. Test and adjust pH to 6.0-7.0 range.
Alter lighting – Increase intensity for lower leaf yellowing. Provide shade for upper leaf scorching.
Control temps – Maintain ideal temps between 70-85°F. Run fans to reduce heat stress.
Treat pests/diseases – Remove infected leaves. Apply organic treatments like neem oil, sulfur, or copper sprays.
Prune old growth – Snip off heavily yellowed fan leaves to reduce stress and refocus growth.
Switch varieties – Try more yellow-resistant strains if genetics are the issue.
Be patient – Some yellowing during flowering or late in life is normal. Just monitor closely.
With a few adjustments tailored to the cause, you can nurse struggling plants back to health and prevent further yellowing.
Why Leaves Yellow During Cannabis Flowering
It’s common for marijuana leaves to turn pale yellow, especially on older fan leaves, as plants transition to the flowering stage. Here’s why this natural yellowing happens:
Maturing foliage – Bottom leaves naturally age and yellow near harvest time. This allows new buds priority access to nutrients.
Nutrient demands shift – Flowering needs less nitrogen. Declining chlorophyll reveals other leaf pigments like carotenoids.
Senescence – Yellowing leaves towards the end of flowering indicates the plant is nearing the end of its natural life cycle.
As long as yellowing is gradual and limited to lower old growth, it is generally nothing to worry about. Monitor for spreading yellowing signalling bigger issues.
How to Prevent Too Much Yellowing While Flowering
While some yellowing is expected, you can take proactive steps to minimize excessive discoloration:
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Provide the right nutrition – Use bloom boosters higher in phosphorus and potassium. Add cal-mag to prevent deficiencies.
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Maintain optimal temps – Keep grow area around 75°F. Prevent heat or cold shock which damages leaves.
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Control humidity – 40-50% RH prevents excess moisture stress on leaves.
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Increase airflow – Improve air circulation to avoid powdery mildew forming on aging leaves.
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Inspect for pests – Treat early signs of mites, thrips, or aphids which feed on leaves.
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Prune strategically – Remove only heavily yellowed leaves, not large amounts of foliage.
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Use foliar sprays – Applying micronutrients and cal-mag topically boosts absorption.
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Pick resistant strains – Some strains naturally yellow less than others during flowering.
With preventative care, you can keep leaves vibrant for peak photosynthesis through harvest time.
When to Worry About Yellow Leaves on Cannabis Plants
While some fading and yellowing is normal, be concerned if you notice:
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Sudden widespread yellowing instead of gradual
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Yellowing not limited to lower old growth but also new leaves and tops
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Mushy, dying yellow leaves instead of just discoloration
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Other issues simultaneously like wilting, spots, drooping
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No improvement after correcting obvious deficiencies like water, nutrients etc.
These are signs of more serious underlying problems requiring investigation. Dig deeper or seek expert help to diagnose mystery yellowing.
Using Nutrients to Correct Yellowing Leaves
Boosting nutrition is one of the fastest ways to restore ailing yellow plants. Some nutrient solutions to try:
Nitrogen – Feed with a nitrogen-rich fertilizer or compost tea. Nitrogen fuels chloroplast production.
Iron – Foliar sprays and soil amendments with iron compounds replenish this yellowing antagonist.
Magnesium – Epsom salts and cal-mag supplements provide magnesium needed for chlorophyll synthesis.
Manganese – Yellowing between leaf veins signals manganese deficiency. Foliars or soil feeds quickly fix.
Sulfur – Needed for amino acid production, sulfur deficiencies cause uniform yellowing.
Target nutrient deficits you suspect through tissue tests or yellowing patterns. Then nourish your pots properly!
When to Remove Yellow Leaves on Cannabis Plants
As long as yellowing is mild, leaves can still benefit the plant through photosynthesis and shouldn’t be overpruned. But if leaves are heavily yellowed, you can remove them to:
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Prevent spreading disease – Infected dying leaves can harbor mold.
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Reduce pests – Mites and aphids congregate on distressed leaves.
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Limit nutrient demands – Plants work less to support dying leaves.
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Improve light exposure – Remove only enough for better penetration to buds.
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Direct growth elsewhere – Cutting inefficient leaves pushes new growth.
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Reduce transpiration – Excessive yellowing can indicate overwatering issues.
Time strategic leaf removal along with the other remedies above to restore plants to health.
Using Variety Selection to Avoid Yellowing
Some cannabis strains and varieties are more prone to leaf yellowing issues than others. If you continually battle discoloration, try switching to yellow-resistant strains like:
- Blue Dream
- Girl Scout Cookies
- Gorilla Glue
- White Widow
- Purple Kush
- Skywalker OG
- Strawberry Cough
- Green Crack
Strains with genetics from cooler, cloudier regions also tend to stay greener than equatorial sativa descendants. Do some research to find yellow-leaf defiant options to try.
Top FAQs About Yellow Leaves on Cannabis Plants
What deficiency causes yellow leaf tips?
Yellow leaf tips are usually caused by a nitrogen deficiency. Boost nitrogen levels with an appropriate fertilizer to green up the leaves again.
Why are fan leaves turning yellow in early flowering?
As flowering starts, bottom fan leaves often turn pale yellow and may drop off. This is natural senescence allowing new buds priority access to nutrients. Monitor for spreading yellowing.
Should yellow leaves be removed from cannabis plants?
Mild yellowing is OK, but severely yellowed or dying leaves can be pruned. This redirects growth, reduces pests/disease, and limits nutrient demands.
What nutrient deficiency causes yellow spots?
Yellow spots between leaf veins typically signals a manganese deficiency. Foliar sprays or soil applications can correct.
How can I stop leaf yellowing and curling?
Curled drooping yellow leaves usually indicate overwatering issues. Allow soil to dry out further between waterings and improve drainage to fix.
Conclusion
While sometimes normal, excessive yellowing of cannabis leaves should not be ignored since it impedes plant growth and bud production. By troubleshooting for common culprits like underwatering, pests, temperature stress, and genetics, steps can be taken to restore leaves to their vibrant green glory. Pay close attention to leaf symptoms and patterns to diagnose and resolve yellowing issues early and quickly. With preventative care, you can minimize unwelcome discoloration and keep leaves photosynthesizing properly for champion cannabis plants.
Should We Cut Off Yellowing Marijuana Leaves?
If the plant is fully grown, you can cut off the leaf that has turned yellow and wrinkly. This energy can be used by the plant to move to healthier leaves. You can help it save energy by getting rid of the dead weight.
Cases When Yellow Leaves Are Not a Problem
There are situations when the yellowing of the leaves is natural and does not require intervention. For instance, the yellowing of leaves is characteristic of plants at the final stage of flowering. This can also happen if the lighting isn’t right, but those leaves can be taken off and the lighting fixed so other leaves don’t turn yellow.