Nitrogen-deficient plants often appear pale or lime-colored. The leaves on this marijuana plant don’t have obvious leaf symptoms like spots or markings, but they are pale all over the whole plant. Almost lime green. The light-colored leaves are a sign the plant needs more Nitrogen (and nutrients in general). On the flip side, plants that are receiving too much Nitrogen turn dark.
Problem: A cannabis nitrogen deficiency will cause the older, lower leaves on your plant to turn yellow, wilt away and eventually die. The plant typically appears pale or lime-colored.
Some examples of cannabis-friendly one-part Vegetative nutrient systems…
The first cannabis plant pictured below is showing signs of nitrogen deficiency late in flowering; nitrogen deficiency in late flowering is completely normal and even desired. The last picture is an infographic about nitrogen and your marijuana plant.
The 3 numbers on the front of plant nutrient bottles list the amount of Nitrogen, Phosphorus, and Potassium.
Occassionally a nitrogen toxicity is mistake for a deficiency. Could your plant actually be nitrogen toxic? (pictured below)
Nitrogen is in all plant nutrient formulations because it’s vital to plant processes.
Nitrogen is a mobile nutrient, which means it can move throughout the plant as needed. Cannabis needs nitrogen to keep leaves green and make energy from light. All new leaves get plenty of nitrogen to make them green and help with photosynthesis. The leaves that get the most light are the newest, youngest leaves, so the plant “wants” to give those leaves priority for getting light.
It’s extra important to find a nutrient system with lower levels of nitrogen for the last part of your plant’s life. Many “Bloom” or “Flowering” style base nutrients are just the ticket.
A nitrogen deficiency causes the lower/older leaves of a cannabis plant to start yellowing, wilting, and dropping off on their own. Learn how to fix it.
If you notice yellowing toward the top of the plant (specifically, nearest the light source), your plants are likely suffering from light burn. Light burn can happen in temperature-controlled environments as easily as those in high-heat if the leaves get too close to the lights. We liken this to getting a sunburn on the ski slopes.
Unfortunately, pests are perhaps the hardest condition to correct, so it’s best to avoid try and avoid them all together. To start, never bring plants or clones from an outside grow into your sanitary grow space and try to avoid entering your grow space directly from the outdoors. Always wash hands, cover your hair and avoid letting pets anywhere near your grow space.
The most common reason plant leaves turn yellow is because of stress. Whether due to inadequate watering, excessive heat, or pest infestations, yellow leaves are a sign of sickly cannabis plants and must therefore be addressed as soon as possible. To understand the science behind this, we must first look at the contents of a typical leaf and its relationship to the plant’s overall health.
After measuring and adjusting pH, take a look at your watering schedule. The most common cause of yellow leaves is either over- or under-watering. Plants that are over-watered will have leaves that seem swollen and droopy while under-watered plants (though much less common) will be thin and frail. Poor drainage can also contribute to overwatering so always grow your cannabis in pots with drain holes.
Wednesday January 29, 2020
Y ou’ve taken great care of your cannabis plants; you water them, feed them nutrient-rich foods, provide the ideal light cycle for their different developmental phases, and prune them just enough to promote light exposure and optimum growth. You’ve done everything right and yet your marijuana plants just don’t look as lively as they should. Specifically, your cannabis plants are showing signs of stress through yellow leaves. Despite all the love and attention you’ve given them, they just aren’t growing into the bountiful beauties you had hoped.
What do you do to fix yellow cannabis leaves? Share your feedback in the comments below.
Temperatures outside of the ideal range of 70 to 80 degrees Fahrenheit also risk discoloration and curl leaves. These oddities are most common in leaves toward the top of the plant and can easily be remedied with a fan (if too hot) or root insulation (if too cold). We also recommend growing plants off a cold cement or tile floor; use a milk crate or stool to raise them off the ground when necessary.
Note that carotenoids cannot directly transform light into energy via the photosynthetic pathway and must pass it onto chlorophyll to finish the job. Therefore, while a minor yellowing leaves will not stop photosynthesis, excessive or unaddressed yellowing can either stunt plant growth or kill the whole thing entirely.
Does your cannabis grow have plants with yellow leaves? Yellowing marijuana leaves can indicate a variety of common ailments. Keep reading to learn more about cannabis plant health and tips to overcome yellow leaves.