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Iron Deficiency In Marijuana Plants

Iron Deficiency In Marijuana Plants

Iron deficiencies pop up every now and then in any marijuana growing system, including planting mediums, hydroponic systems, and outdoor planting.

Iron is a necessary nutrient that is used to help with a marijuana plant’s young, growing tissues.

Iron is needed to help enzymes function well or for chlorophyll to synthesize properly. If your plant is lacking in iron, it will have problems. Read this article and learn how to recognize and fix an iron deficiency.

Signs of an iron deficiency

Sings of iron deficiency cannabis

If your plant has an iron deficiency, their new leaves will start lacking in chlorophyll. There won’t be any necrotic spots, as with some other nutrient deficiencies, but the leaves will turn a bright yellow while retaining their green veins.

New leaves will show signs of chlorotic molting, which will make the center of the leaves have a brown mark. Other signs include upper fan leaves and smaller inner leaves turning yellow. Occasionally these leaves will even turn white. Most often you will see symptoms toward the top of the newer leaves.

Download my free marijuana grow guide at this link for more growing tips

Iron deficiencies resemble magnesium deficiencies, with the exception that iron will affect every bit of new growth other than the leaves toward the bottom of the plant. Magnesium, on the other hand, will affect the middle and lower leaves from the beginning. Iron is low mobility so you won’t see too much movement in where the plant is affected.

Not sure if your plants have an iron deficiency? Read the article Nutrient deficiencies in marijuana plants for a list with pictures of all deficiencies.

How to fix an iron deficiency

How to fix iron deficiency cannabis

Like with many other nutrient deficiencies, using an all-around nutrient provider like Marijuana Booster is going to work best. You can also choose a foliar feeding method that includes a chelated iron fertilizer. This will also help with zinc and manganese, which is helpful since deficiencies in iron, manganese, and zinc often occur together.

You can also use iron chelates, iron oxides (Fe203 or FeO), or iron sulfate (FeSO4), which should be added filially and right into the planting medium. Surprisingly, you can also just use rusty water.

Also similar to other nutrient deficiencies, a marijuana plant with iron deficiency could be suffering from an unbalanced pH level. This occurs more often in soil than in a hydroponic system. Read the article How to measure the pH of your soil and test the pH of the soil around your plant’s roots to make sure this is indeed the problem.

In soil, the pH level should be between 6.0 and 7.0. Roots absorb will absorb iron best if you can ensure the pH level is low enough, so try getting it down to at least 6.5 if you can. In a hydro system, iron will be taken in by the roots most efficiently when the pH is between 5.5 and 6.5.

In order to fix the pH level of your system, simply flush out the entire system with fresh water that has the proper pH level as well as a boost of nutrients to restore the balance.

Download my free marijuana grow guide at this link for more growing tips

Sometimes growers cause an iron deficiency themselves by over-fertilizing their plants. Chicken manure, for instance, increases the soil’s pH level. An increased pH level is most often responsible for the iron deficiency. Chicken manure also might block the iron from being absorbed into the roots of your marijuana plant.

This shows that often the problem is not actually the amount of iron that is in the soil, but rather something that is keeping your plants from accessing that iron. If you have caused an iron deficiency with too much manure, you will need to dig up that fertilizer and replace it with high-quality soil.

Once you solve the pH or iron content problem, you should start seeing signs that your plant is “feeling” better. Don’t look to the older leaves and growths for signs of improvement, as they most likely won’t ever recover. Instead, keep an eye out for new growths. If they look green and thriving (not yellow at all, like you experienced when your plant was iron deficient) then you can safely assume the iron deficiency is no longer a problem!

Learn more about marijuana nutrients and read the article All about marijuana nutrients.

List of marijuana plant symptoms

– Pale leaf color
– Yellow color of new leaves
– Yellow color between veins
– Leaf veins remain green color
– Upper and newer leaves affected
– Small inner leaves affected
– Death of leaf tips
– Slowed growth
– Abnormal or twisted growth
– Buds not getting fatter

The tricky thing about adding in iron is that it can easily have a reaction with another nutrient, thus locking those nutrients out. You, therefore, should make sure that, if you’re supplementing your system with iron, you read the label and understand how it could interact with other nutrients. This will help you avoid adding more problems to the mix.

Remember that plants with strong genetics have less change of getting sick. Make sure you buy marijuana seeds from a trusted seedbank.

Thanks for reading. Please leave comments or questions below and don’t forget to download my free grow bible


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Comment Section

9 thoughts on “Iron Deficiency In Marijuana Plants

By per on 5 September 2013

this was a very nice cite,Ihope it will help me alot, Thanks

By George Graeber on 3 February 2017

EDDHA Iron Chelate versus EDTA Iron chelate…. what is the difference?
EDTA Iron fails when the pH exceeds 6.8. EDDHA remains available from a pH of 4.8 to 10.5
EDTA is often found in blends like 20-20-20 and remains availble for 3-10 days. EDDHA Iron remains available for 3-5 months. The EDDHA Iron molecule is significantly smaller than EDTA Iron… so it moves into the plant via mass flow.
When growers move from the Veg Stage to the Bud production stage they often will stop using 20-20-20 and by default, the EDTA Iron is gone within 3-7 days. By the time they reach harvest the plant is very yellow. If you want to see dark green foliage all the way thru harvest without a flush of growth, consider EDDHA Iron.
Consider the cosmetics too. I have strawberry growers who use EDDHA Iron for the purpose of making the calyx and stems dark green. Buyers get turned on to the way the berry is presented. Same goes for Cannabis Buds.
Nabta manufactures water soluble fertilizer, chelates and humic acid. Nabta sol EDDHA 6% Iron chelate is ground down to a very fine powder and can be applied as a drip/drench or as a foliar application. The only cautions are not to apply with Calcium… and do not apply as a foliar during periods of bright sunlight.

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