Chlorosis

No, it’s not a new brand of mouthwash.

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Chlorosis refers to the yellowing or bleaching of leaves frequently caused by insufficient iron in the soil. It can also be caused by inadequate light or too much water.


Plants suffering from chlorosis are unable to produce chlorophyll. Since chlorophyll is what plants use to help them convert sunlight into energy, in a process called photosynthesis, it’s pretty important.

Photo of chlorotic celery leaves by Kate Russell

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If you notice chlorosis on any of your plants, ask yourself the following questions:

• Is it getting enough sunlight?
• Am I over-watering? 
• Is the soil permeable?
• Does the soil provide adequate nutrients?
• Are any pests present?

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If the plant is being watered properly and getting enough sunlight, the problem is probably a mineral deficiency. The only way to really know what is in your soil is to send samples to a local, reputable lab.  Over-the-counter soil tests are generally a waste of money.


When I submitted soil samples to the Extension office, I learned that my soil has an abundance of every nutrient known to humankind, except iron.


Plants use iron to process nearly every other nutrient, so it is critical to healthy plants. Unlike nitrogen, which can move freely within a plant, once iron is absorbed, it stays where it is. You can add iron to the soil or, for faster results, you can apply foliar (leaf) sprays. Low levels of zinc or magnesium can also cause chlorosis, as can certain pathogens, the wrong pH, or compacted soil.
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As soon as your plant has adequate sunlight, the correct amount of water, healthy soil, and sufficient iron, its little energy factory will kick right in and everything should start greening up pretty quickly.