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What is a Sulfur Deficiency in Plants?

Sulfur is an essential mineral required for plants to achieve optimal health and growth. Approximately 10 to 30 pounds of sulfur are required for each acre. Sulfur helps with the conditioning of the soil in addition to decreasing sodium content. If the sodium content is too high, plants are unable to grow properly. Certain vitamins contained in plants require sulfur as an essential component.
Sulfur greatly enhances the flavor of numerous plants including garlic, onions and mustard. Plants are unable to convert energy received from the sun into new growth without sulfur. Sulfur is also critical for producing chlorophyll. This is the reason a sulfur deficiency in plants results in yellowing leaves. Sulfur is necessary for the metabolization of nitrogen.
For this reason, if there is a sulfur deficiency, a nitrogen deficiency is present as well. This means when sulfur is not available, a nitrogen deficiency is created. Plants require sulfur for numerous processes including vitamin, enzyme, amino acid and protein production. Sulfur increases the resistance of plants to diseases, helps with seed formation and assists with growth.
How Does a Sulfur Deficiency Affect the Quality of Your Plant?
Although a deficiency in sulfur is rare, the quality of the plant will be affected. This deficiency triggers chlorosis, leading to the leaves becoming yellow. In most instances, the new leaves are the first to show symptoms of a deficiency. A sulfur deficiency is generally mistaken for a lack of nitrogen. The undersides of the leaves often turn orange or pinkish red.
Buds on a flowering cannabis plant often begin to die. Although several other conditions can cause yellowing leaves, a sulfur deficiency in plants is different. This is because the yellow first appears toward the rear of the leaf. As the deficiency worsens, the yellowing moves forward. Many other deficiencies begin at the tips of the leaves.
What are the Symptoms of a Sulfur Deficiency?

A sulfur deficiency generally results in one or more of the following symptoms:
- Older leaves turn yellow
- Interveinal striping
- Lower older leaves often remain green
- Delayed leaf maturity
- Slow growth
- Yellow areas between the veins
- Cannabis buds do not thicken properly
The most classic sign of a sulfur deficiency in plants is the yellow coloration of the older leaves. The color of the leaves change beginning with the tip of the leaf, then proceeding all the way to the midrib. Older leaves often become discolored in the whorl. In some instances, interveinal striping is present. A uniform green coloration remains on the older and lower leaves.
A sulfur deficiency often results in delayed maturity and slower growth of the leaves. If the deficiency advances, the yellowed leaves will spread throughout the plant. In most cases, there is a deficiency in both sulfur and nitrogen. Detecting a sulfur deficiency in plants is more difficult because the deficiency must generally become severe before any symptoms appear.
Buds on cannabis plants are unable to thicken properly. Plants with stronger genetics are less susceptible to deficiencies or disease.
Possible Confusion with Other Symptoms
- Since sulfur and nitrogen deficiencies usually occur at around the same time and are similar, there is a lot of confusion between the symptoms of the two.
- Yellowed leaves can be mistaken for light stress or burn, in addition to several other nutrient deficiencies
- A nitrogen deficiency also results in the yellowing of older leaves
What Causes a Sulfur Deficiency?
The most common causes sulfur deficiency includes:
- Low supply of soil
- No fertilization
- Sandy and weathered soil
- Soil containing excess iron
- Heavy rainfall
A sulfur deficiency is often caused by no fertilization or a low supply of soil. Smaller plants are more susceptible. Burning vegetation, saturating the soil and heavy rainfalls often result in a sulfur deficiency in the soil. Sandy or weathered soil and soil with a high concentration of iron can cause a sulfur deficiency. Because sulfur is water-soluble, strong rains can leach sulfur from the soil causing a deficiency.
How to Fix a Sulfur Deficiency in Plants
The best remedies include:
- Use fertilizer with sulfur
- Ensure the content of organic matter is high
- Correct the pH level
- Use Epsom salts
- Treat plants using gypsum or garden sulfur

A sulfur deficiency in plants can usually be corrected by using a fertilizer rich in sulfur. Fertilizers offer a high enough quantity of sulfur for enriching the soil. The availability of sulfur to the roots of the plants is enhanced when a high content of organic matter is maintained.
Organic matter also reduces how much sulfur is leached from the soil. The pH balance for every growing medium needs to be checked to make certain sulfur has not been locked out.
The easiest solution for a sulfur deficiency is using Epsom salts. Simply water the affected plants using Epsom salts until the issue is resolved. One to two teaspoons of Epsom salts should be added to every gallon of water.
Other nutrients containing sulfur can be added at the same time such as gypsum or garden sulfur. If the pH level is less than 5.5 do not add gypsum or the soil will become toxic for the plants.
How Long Does It Take for a Plant to Recover from a Sulfur Deficiency?
Sulfur is unable to move quickly throughout plants. For this reason, a few days are required once the issue has been corrected before any improvements become apparent in the plants. The sulfur deficiency should be corrected within a few days.