Sulfur Deficiency in Cannabis Plants: Symptoms, Reasons, Cure
The last thing cultivators like to see on their cannabis plants is yellow leaves. Apart from robbing your growing space of a sea-of-green look, it discourages healthy development. A sulfur deficiency in weed plants is rare but still happens under unfavorable conditions.
Marijuana plants depend on sulfur (S) to perform vital processes to sustain healthy growth. Although it’s not used as much as primary nutrients like nitrogen (N), phosphorus (P), and potassium (K), without it, plants become unhealthy.
Find out what causes a sulfur deficiency, what the symptoms are, and how to restore the health of your crop before it’s too late.
What does sulfur do for weed?
Cannabis plants thrive on the availability of all the essential macro and micronutrients. They all play a specific role in the growth characteristics of the plant. Whether they’re N, P, or K or less recognized ones like copper (Cu), magnesium (Mg), or in this case, sulfur.
S is a less discussed nutrient, primarily since a deficiency rarely occurs. In addition, the element is hardly ever displayed on fertilizer packaging, so it’s natural to think it’s not as vital as the primary three nutes.
Most growers only become aware of the importance of sulfur when facing a deficiency of the nutrient in their crops. Wondering why your plants look defeated by the odds of nature? Find out why they need a mineral like S.
Sulfur is a semi-mobile secondary macronutrient cannabis plants use in large quantities to:
- Maintain root health
- Produce chlorophyll through photosynthesis
- Metabolize nitrogen
- Increase plants’ resistance to cannabis diseases
- Enhance the growth of plants
- Assist water and nutrient absorption processes
- Helps with seed formation
The availability of S in marijuana crops assists with strengthening stems and healthy bud production. Cannabis plants use it during the seedling, vegetation, and flowering stages. In addition, it’s a vital component in forming plant proteins and amino acids.
In nature, sulfur is available in its pure form as a yellow mineral that plants can’t absorb through their roots. It’s found in soil as sulfates (salts of sulfuric acid), the only way crops can utilize it. Most commercial nutrient stockists have this available.
It’s, therefore, vital to use the best cannabis fertilizers containing sufficient amounts of sulfur.
Chlorophyll is the green pigment that gives cannabis leaves their staple color. Plants need it to absorb light and convert it into energy through photosynthesis.
Sulfur is an essential mineral that allows marijuana plants to perform respiratory functions and aids in synthesizing oils and terpenes. This mineral decreases sodium content by conditioning the soil, which promotes plant growth.
Conversely, high levels of sodium in growing mediums discourage maturation.
Signs of sulfur deficiency in cannabis
Cannabis nutrient deficiencies show similar characteristics. It’s vital to know the difference and fix them accordingly. Most defects present ill-looking leaves. Identifying the starting point of the symptoms is what sets an S deficiency from a nitrogen one.
A sulfur deficiency in cannabis affects the physical appearance of the buds as well as their flavors and aromas.
With a lack of potassium in weed, for example, yellowing begins at the tips. When crops lack sulfur, the first signs of discoloration start at the back of the leaf and move toward the center. You may even notice the underside of the foliage changing to a pinkish, red, or orange color.
Sulfur deficiency most often shows the following symptoms in weed leaves:
- Burnt leaves tips
- Complete chlorosis in young leaves toward the top of a cannabis plant
- Leaves yellowing starting from back
- Leaves become lime green before turning yellow at the center
- Veins are yellow
The discoloration process from the petiole toward the leaf edges is called complete chlorosis. New leaves and stems turn yellow as chlorophyll becomes absent from the plant material.
It’s vital to know that sulfur and nitrogen deficiency share similarities. The part of the plant that shows leaf discoloration first determines the difference between the two. When crops lack N, the symptoms start in lower, older foliage.
Newer leaves toward the top of a cannabis plant are the first to show signs of an S deficiency. First, they become lime green before turning yellow at the center. The color then starts to spread toward the edges as the defect in the plant progresses.
Burnt leaf tips eventually make their way to the foliage if you don’t attend to the S deficiency on time. The affected areas begin drying out, causing the leaves to bend downwards before dying and falling off.
The yellowing color at the center of leaves is a sign of a drastic loss of chlorophyll concentration. At this point, your crops aren’t absorbing enough light to turn into energy and food.
A cannabis sulfur deficiency leads to fragile foliage that doesn’t progressively grow. You’ll also notice yellowing between the veins as time goes by.
Due to a lack of chlorophyll, natural or artificial light burns the leaves causing necrotic spotting on the base.
Sulfur deficiency most often shows the following symptoms in weed plants:
- Stuned growth
- Flowers fall off
- Stems turn woody
- Lower yields
Weed nutrient deficiencies are detrimental to your cannabis plants. Apart from affecting the foliage, they also impact the structure. For example, when sulfur availability is low, you’ll notice much slower growth patterns and fewer branches.
When the plant can’t convert energy into food, it loses vigor, causing it to look run-down. As a result, the stems remain thin and can’t support the weight of the leaves and colas.
The most inconvenient time to experience an S deficiency is during flowering. Underdeveloped crops produce immature buds. The flowers fall off after dehydrating, resulting in lower yields.
Symptoms become clearer as parts of the stem also turn yellow.
The reasons for cannabis sulfur deficiency
A distinctive cause of an S deficiency in marijuana plants is the incorrect pH levels in the soil. It’s usually the result of unfavorable issues relating to your growing medium or maintenance schedule.
Choosing the wrong fertilizers for your cannabis plants can result in the loss of sulfur. The sulfur concentration isn’t always listed on nutrient packaging, resulting in an under- or over-feeding of the mineral.
Marijuana crops need sulfur to metabolize nitrogen. Therefore, when there is a lack of this mineral, it could create an N deficiency.
Poor-quality grow mediums encourage a sulfur deficiency in weed plants. While S is a mineral naturally available in the soil, buying cheap brands may contain too little or be without the nutrient.
Be mindful when purchasing fertilizers, too. Not all have sufficient quantities of sulfur. At times it’s only listed as an ingredient, and growers often overlook the accessible portions.
Soilless mediums suffer the most in this case since the crops depend on the nutrient amounts cultivators feed. If growing in a controlled environment, use ideal nutes for raising crops from indoor weed seeds.
An incorrect pH level in soil leads to nutrient deficiencies or toxicity in marijuana crops.
The correct pH ranges for your growing mediums:
- Soil: 6.0–7.0
- Hydrogen: 5.5–6.5
- Coco coir or peat moss: 5.5–6.5
When the pH level in soil or other mediums is below seven, it’s too acidic, while anything above eight is too alkaline.
How to fix the sulfur deficiency in weed plants
After identifying the problem, eliminate it from your crops to deter further damage. Learn how to fix a sulfur deficiency in plants and be a step ahead of future defects.
The first thing to do is check the pH levels in your growing medium. Ensure that they’re within the ideal ranges for nutrient absorption.
If the pH levels aren’t the issue, it’s most likely time to amp up the sulfur feed. A great way to stop the deficiency from spreading is to use Epsom salts (Mg sulfate). Mix one teaspoon of magnesium sulfate for every liter of water and sprinkle over the soil.
This organic supplement doesn’t reverse leaf discoloration or necrotic spotting but deters the spread to new plant material.
Knowing how to water cannabis is a crucial step in your maintenance routine. If you’re only feeding your plants with plain H2O, it could also lead to a sulfur deficiency.
A balanced feed provides the crops with their required nutrients for each growth stage. Pay attention to ratios when mixing the nutes with water.
When fixing a sulfur deficiency in marijuana crops, use a quality water-soluble fertilizer after providing the Epsom salts mix. It may take a few days before seeing an improvement in your plant since S moves slowly.
Use soil that’s rich in minerals when cultivating from outdoor weed seeds.
What is sulfur toxicity in cannabis, and how to treat it?
Overstimulating the growing medium with nutrients initiates a cannabis nutrient burn, also known as nutrient toxicity. As a result, plants become stressed, leading to discolored, curled, and withered leaves. In addition, too much of one nute may block out others.
Whereas a shortage of sulfur causes a deficiency in cannabis plants, excess leads to toxicity. Find the middle ground of the plant’s nutrient requirements to avoid under or overfeeding it. Too much S deters the absorption of nitrogen and calcium.
The defect likely occurs when the pH levels are out of balance. If it’s too low, the soil is too acidic, which could lead to sulfur toxicity.
Unlike yellowing leaves with a cannabis sulfur deficiency, they become dark green during toxicity. In addition, the leaf tips seem burnt as they take on a brown color.
Get rid of the toxicity by flushing your growing medium with clean pH-balanced water. Do this by running four times as many fluids as the pot’s capacity to rinse all nutrients.
The pH range after the rinse is usually between 5.5 and 6.0. Once you’re happy that your medium is nute free, continue to feed your crops with water for a week. After this time elapses, use a balanced fertilizer containing all the nutrients for weed cultivation.
Yellow isn’t the new green
If it’s fat buds you want from your marijuana crops, ensure it never lacks sulfur. Unhealthy plants can’t produce delectable buds without the support of all the necessary nutrients.
Looking at yellow or dark green leaves (from toxicity) on your plants is an unpleasant sight for any grower’s eyes.
Stay on top of your maintenance schedules by regularly checking pH levels in your growing mediums. Then, use a nutrient guide to get the mixing ratios right for feeds.
Don’t let a sulfur deficiency in your weed discourage you from cultivating cannabis. Instead, kick defects to the curb and start fresh with reputable seeds from our store. Your crops won’t have time to be short on anything with all the attention it’s getting from you.