Rust Colored Spots on Cannabis leaves-Preventing And Fixing

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    Rust Colored Spots on Cannabis Leaves

    Healthy Cannabis plant leaf

    Identifying, Preventing, and Curing Rust Spots 

    Rust spots or orange spots on cannabis leaves are caused by the following:

    • Cannabis Rust Fungus
    • Nutrient Deficiency
    • Pests

    Of the above, rust fungus is the most common reason for these unsightly specks appearing on a cannabis plant. I will go over each of these above situations and then go over preventative measures and ways to cure this issue.

    Rust Fungus

    Rust Fungi Example
    Rust Fungus Example

    Why Should I Care? With out-of-control rust fungal disease, your plant leaves will curl, fall off, and your plant growth will be stunted. What is worse, though, is that the fungi easily spread and affect your other plants. So, you need to make sure that all rust fungi-affected leaves, especially fallen leaves, are removed and disposed of properly.

    First Things First-Is It Rust Fungus or Something Else?

    Rust fungus frequently appears during the flowering growth stage and is caused by fungal spores that travel from plant to plant. They appear on almost all green, leafy plants, and are a leading cause for these spots appearing on your plants. However, there are other reasons for these spots. So, before trying to fix a rust fungus issue, first, inspect an infected leaf to determine what the problem may be.

    Tests

    Rust fungus normally appears during the flowering growth stage. It can be detected visually and by touch. Visually, they can be identified by multiple rust-colored spots appearing on the leaves. (There can be hundreds of these specs or spots on a single leaf) And with a touch test, you rub your finger on an affected leaf, if, after rubbing, the spots disappear and stick to your finger or elsewhere, you have a fungus or powdery mildew problem. If the spots remain it is most likely a cannabis nutrient deficiency issue.

    What Causes Rust Colored Spots To Show Up?

    Rust disease, is a fungal parasite that thrives in a temperate, moist environment, and is spread by air, and even water. As it is parisite, it lives off of other plants. Once a plant is affected, the fungal spores then infect other nearby plants. And when the leaves are damaged it is harder for a plant to absorb its nutrients. This results in a stunted plant that will eventually die.

    Preventing Cannabis Rust Fungus

    A rust fungus-infected plant cannot be cured. As a result, any affected leaves or stems will need to be carefully discarded. So, prevention is the key. Fortunately, there are several methods of prevention.

    Setting Up Your Grow Area

    Cannabis Grow Room
    Cannabis Grow Room

    The first step you should take is to ensure that your grow area is at the ideal temperature, adequately ventilated, sanitary, and the air circulates properly. One simple way to assure proper air circulation is by making sure your plants are not placed too close together. So, be sure to not crowd your grow tent.

    Choose A Fungi Resistant Strain

    Purchasing mold-resistant cannabis strains is the best way for you to start out ahead. This article has information on eight highly resistant mold-resistant cannabis strains. For more strains, just Google “Mold Resistant Strains.”

    Apply Preventative Fungicide

    Ancient Greeks first used sulfur fungicide over 2,000 years ago. As a result, sulfur is the most time-tested organic fungicide available and helps with rust fungus, powdery mildew, and other plant diseases by stopping fungal spores from germinating. Please note, it only prevents fungal spores from appearing, and once an infection occurs, sulfur fungicide is useless

    Bonide (BND141) - Sulfur Plant Fungicide, Organically Controls Rust, Leaf Spot and Powdery Mildew (1 lb.)

    Lime-Sulfur- Lime sulfur is sulfur that is mixed with calcium hydroxide or lime. It is overall more effective. But, it smells like rotten eggs and should not be used on plant leaves.

    Is Sulfur Fungicide Safe?-Sulfur is generally safe. However, you should wait for 30 days to use it after you have used an oil spray on your plants. Also, it is best used when your grow room temperature is below 80 degrees.

    Neem Oil

    Organic Neem Bliss 100% Pure Cold Pressed Neem Seed Oil - (16 oz) High Azadirachtin Content - OMRI Listed for Organic Use

    Neem Oil is an organic pesticide and fungicide that is helpful in getting rid of rust disease.

    Don’t confuse Cannabis Leaf Septoria with Rust Disease?-Leaf Septoria, is another affliction that affects the leaves of a cannabis plant. Septoria differs from rust fungus, as a plant affected has yellow leaf spots, appearing on the lower leaf,and not rust-colored spots.

    Nutrient Deficiencies

    A cannabis nutrient deficiency is another reason for unsightly spots appearing on a plant leaf. Some of the more common deficiencies are magnesium deficiency and calcium deficiency.

    Be wary of nutrient burn-Overfeeding your plants can be as harmful as not giving you plants enough nutrition.. Overfeeding or over-fertilizing causes nutrient burn, which results in your leaves browning (sometimes the color is reddish), edges drying or curling up, and root damage. Damage done by a nutrient burn cannot be repaired. However, it can be easily recognized, which means that if you pay attention you can stop it from getting any worse.

    Calcium, and Magnesium Nutrient Deficiencies

    Magnesium Deficiency

    A magnesium deficiency is the most common form of nutrient deficiency that you will see in cannabis, and it is signaled by rust spots and leaves turning yellow.

    It can be caused by not enough magnesium or when a plant is not able to properly absorb the nutrient.

    How Can It Be Prevented?

    To prevent it, apply a fertilizer that has magnesium. A spray that uses Epsom salts, like the one shown below, will work.

     Magnesium Sulfate
    Magnesium Soil Additive

    Calcium Deficiencies

    A calcium deficiency is indicated by a leaf having brown edges and/or curly-leaf tips. For a calcium deficiency, you’ll be more likely to see brown spots instead of rust spots. However, it can sometimes be tough to differentiate between the two.

    At first, it starts small and is barely noticeable. But, once it gets going, it will come on like gangbusters. You cannot cure a calcium deficiency problem; you can only control and limit the damage, as delaying or ignoring this problem will only make it worse.

    Prevention and Treatment

    Soil that has a 6.4 pH level or less can cause a deficiency. So, regularly check on your soil PH levels to prevent this from happening. If you do have this problem, apply measures to increase the soil PH levels. Also, you should consider using gardening soil that contains peat.

    Other Nutrient Problems

    There are multiple nutrient problems that affect a plant’s leaves. Some of which are zinc deficiency, potassium deficiency, and iron deficiency. Each of these problems does not cause rust-covered spots on the plants. So, they are only briefly mentioned. However, a competent cannabis grower should know about and identify each of these problems. For further info, click one of the above links.

    How to Fix A Fungal Rust Infection

    Fungal disease spreads easily, and a diseased leaf cannot be saved. You may though be able to save other non-infected parts of the plant. So, as stated, preventing this from happening is critical. But, if you do have it, you need to do the following:

    • Remove -First, thoroughly and quickly, remove and dispose of any affected leaves.
    • Apply Fungicide – After clearing and disposing of every infected leaf, you need to spray the remaining healthy plants. The following is highly recommended on Amazon and is specifically designed to deal with fungicide.
    • Properly Dispose of All Damaged Leaves– This step is extremely important as cutting corners can negate any hard work you have done to remove any diseased leaves. Either burn or thrown away any affected plant. So, do not place any of the leaves in a mulch pile, and be sure that the leaves are far away from your healthy plants.

    Pest Infestation

    A hemp russet mite or a spider mite is a pest that also can cause spots on leaves. However, instead of red, the spots will most likely be a distinctive brown or yellow color. Check out this article for information on getting rid of spider mites during flowering.

    microscopic spider mite
    Micro View of Spider Mite

    Conclusion

    Rust colored spots on your cannabis plants are one of the many problems you need to address as a grower. A cannabis rust fungus is the most common reason for this to occur. A rust-infected plant cannot be cured. Therefore is essential that you are able to find out the signs of rust disease and also how to deal with an outbreak. Also, a cannabis gardener will need to know how to detect and deal with a nutrient deficiency. All of the above issues can be prevented or controlled. So, practice proper gardening procedures, recognize any problem signs as early as you can, and you should be fine.

    Rust Colored Spots on Cannabis Leaves

    Rust Fungus Cured! Cannabis

    Identifying, Preventing, and Curing

    Rust spots on cannabis leaves are most likely caused by four situations, which are the following.

    • Cannabis Rust Fungus
    • Calcium Deficiency
    • Magnesium Deficiency
    • Nutrient Burn
    • Pests

    Of the above, rust fungus is the most common reason for these unsightly specks appearing on a cannabis plant. I will go over each of these above situations and then go over preventative measures and ways to cure this issue.

    First Things First

    The first step for you to take before you begin to address this issue is discovering exactly what is causing the spots to appear.

    Rust fungus, which can appear on almost all green, leafy plants, is the leading cause for these dots to appear on your plants. However, there are other reasons for these spots. So, never assume that it is a fungus problem, nutrient deficiency, or other problems.

    Tests

    A mold or fungus infestation be detected visually and also by touching. It can be visually recognized as it causes plants to have multiple rust-colored spots on the affected leaves. (There can be hundreds of these specs or spots on a single leave) Also, the spots

    Once you see any spots on your plants, rub your finger on an infected leaf. If, after rubbing, the spots are removed, and they go onto your finger or elsewhere, you have a fungus or powdery mildew. However, if the spots remain there after being touched, it is most likely a nutrient deficiency issue that needs to be addressed.

    Rust Fungus

    Why Should I Care?

    When you have an out-of-control rust fungal disease, your plant leaves will curl and eventually fall off, resulting in stunted plant growth. What is worse, though, is that it will spread and ultimately affect your other plants. So, you need to make sure that all rust fungi-affected leaves, especially includes fallen leaves, are removed and disposed of properly.

    How Is It Different From Cannabis Leaf Septoria?

    You may have heard of leaf septoria, which is another affliction that affects plants. It is different, however, from rust fungus, as a plant affected with septoria will have a yellow leaf spot and not rust-colored spots. These yellow spots will first appear on the lower leaf of a plant.

    What are the Causes?

    Rust fungi can thrive on all, green leafy, plants given the right conditions, which are the following:

    • Between 60 to 80 degrees
    • High overall humidity.
    • Rust spots on cannabis leaves will happen most likely during flowering.

    Unfortunately, the above is also considered to be the best conditions for growing marijuana.

    Preventing Cannabis Rust Fungus

    After a plant is affected it cannot be cured. As a result, any affected plants will need to be carefully discarded. So, prevention is the key to dealing with rust fungus. Fortunately, there are several methods of prevention.

    Grow Room Environment

    The first step you should take is to ensure that your grow area is at the ideal temperature, adequately ventilated, clean grow room, and that the air circulates properly. Proper air circulation can be done by making sure your plants are not placed too close together. So, be sure to buy the correct size grow tent.

    Fungicide

    You should supply a sulfur-based fungicide. Some examples that are rated highly are the following:

    Bonide (BND1428) - Sulfur Plant Fungicide, Organically Controls Rust, Leaf Spot and Powdery Mildew (4 lb.)

    Neem Oil is also recommended.

    Organic Neem Bliss 100% Pure Cold Pressed Neem Seed Oil - (16 oz) High Azadirachtin Content - OMRI Listed for Organic Use

    Fixing It

    It spreads easily. So, as stated, preventing this from happening is critical. But, if you do have it, you need to do the following:

    • Remove-You must first remove and dispose of any affected leaves. Rust fungal spores can spread quickly. So, you need to be sure that you do this quickly and thoroughly.
    • Apply Fungicide– After clearing and disposing of affected plants, you need to apply a fungicide to the remaining plants that do not have any problem. The following is highly recommended on Amazon and is specifically designed to deal with fungicide.
    • Proper Dispose Of All Damaged Leaves-Make sure that any infected plants are either burned or thrown away. So, do not place any of the leaves in your mulch pile.

    Choose A Fungi Resistant Strain

    Fungi Resistant Strains

    One way to reduce the chance of having these spots on your plant leaves is by purchasing mold-resistant cannabis strains. The following are the five best mold-resistant strains that Royal Queen Seeds recommend.

    • Stress Killer Automatic-(Hybrid)-Sativa Dominant
    • Shinning Silver Haze-(Hybrid)-Sativa Dominant
    • Power Flower-(Hybrid-Sativa Dominant
    • Royal Moby-Sativa Dominant
    • Northern Light-100% Indica

    Click Here for more information on these above strains.

    There are many more mold-resistant strains. For further research, I would look at the following websites:

    Also, just Google “Mold Resistant Strains,” and you’ll find hundreds of other strains.

    Magnesium Deficiency

    Rust spots, along with leaves turning yellow, are a few ways to identify magnesium deficiency.

    A magnesium deficiency is the most common form of nutrient deficiency that you will see in cannabis. Of course, it can be caused by not enough magnesium. However, it also can happen when cannabis is not able to absorb magnesium efficiently.

    Some of the reasons why it would not absorb correctly are below.

    • Too much calcium, potassium, or ammonium, in proportion to the magnesium
    • Very damp, cold, or acidic roots
    • Stunted plant roots
    • Improper, EC, hydroponics ratings.

    How Can It Be Prevented?

    To prevent it, apply a fertilizer that has magnesium. A spray that uses Epsom salts, like the one shown below will work. Monterey LG7220 Epsom Salt for Plants Magnesium Sulfate for Gardening, 4 lb

    Calcium Deficiencies

    Calcium deficiencies also can result in these spots appearing with a dark brown edge or outline. Curly-leaf tips with the aforementioned spots can also signal a deficiency. For a calcium deficiency, you’ll be more likely to see brown spots instead of rust spots. However, it can sometimes be tough to differentiate between the two.

    Calcium deficiency starts small and is barely noticeable. But, once it gets going, it will come on like gangbusters. You cannot cure a calcium deficiency problem; you can only control and limit the damage caused by calcium deficiency. And delaying or ignoring this problem will only make it worse.

    Prevention and Treatment

    Soil that has a 6.4 pH level or less can cause a deficiency. So, regularly check on your soil PH levels to prevent this from happening. If you do have this problem, apply measures to increase the soil PH levels. Also, you should consider using gardening soil that contains peat.

    Nutrient Burn

    Just like people, you can overfeed your plants. Overfeeding or over-fertilizing plants causes a nutrient burn, and it results in your leaves browning (sometimes the color is reddish), edges drying or curling up, and root damage.

    Damage done by a nutrient burn cannot be repaired. However, it can be easily recognized, which means that you should stop any further damage from occurring if you pay attention.

    How to Fix It

    It is fixed by doing the following:

    • Discard– Remove all damaged leaves and flowers.
    • Clean It Up -Flush out what you are growing your marijuana in (“medium”) with pure water.
    • Treat It -Treat your remaining plants with a plant tonic composed of humic, fulvic acid, and humic, and other assorted vitamins and minerals.
    • Fertilizing – To stop it from reoccurring again, only use a fertilizer that has 3/4 strength.

    The following is a summary of how to fix “nutrient burn.” Click Here for a more thorough explanation.

    Pests Infestation

    A hemp russet mite or spider mite also cost spots on leaves. However, instead of red or orange, the spots will most likely be a distinctive brown or yellow color. Check out this article for information on getting rid of spider mites during flowering.

    microscopic spider mite
    Micro View of Spider Mite

    Conclusion

    Rust-colored spots on your cannabis plants are one of the many problems you need to address. Rust fungus is the most likely reason for these rusty specks on your plants. All of the above issues can be prevented or controlled. So, practice proper gardening procedures, recognized any problem signs as early as you can, and you should be fine.

     


    Top 10 Newbie Friendly Cannabis Seeds

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