Molybdenum deficiencies and how to fix

What is a Molybdenum Deficiency? How do I fix it?

Molybdenum (Mo) is not only difficult to pronounce, (molyb-den-um) it is a needed element in gardening to accelerate nitrogen metabolism in plants.

It does this by converting nitrates into nitrites helping synthesise essential amino acids within the plant.

In legumes, this relationship between Mo and N helps fix atmospheric nitrogen to root bound rhizobia that then provide for the host plant.

Molybdenum is usually found in most ‘growth’ promoting nutrients, it is usually amended in very small percentages, some as low as 0.001%

Molybdenum is very reliant on pH stability to be fully up-taken by the plant, the reason stability with this element is crucial is because of how slow it moves through the plant.

If the pH stability of your nutrient solution has too many ‘daily’ incremental changes, the absorption of Mo is compromised and as such, the plant must restart the process.

Molybdenum is commonly found in soils with elevated pH levels.

Plants low or deficient in molybdenum almost always present severe deficiencies of other crucial elements, usually paired with the onset of magnesium and zinc as well as other micro nutrients.

If molybdenum has taken hold of your flowering plants, the best way to fix this is:


Coco or soil growers:

Flush, with plain pH water (6.0-6.5)

Raise the pH of your nutrient solution

Remove necrotic growth

2-4-week recovery time.


Hydroponic growers:

Flush, with plain pH water (5.6-6.2) below 5.5 (Mo) is unavailable to the plant!

Raise the pH of your nutrient solution

Remove necrotic growth

2-3-week recovery time.


How to avoid a Mo deficiency going forward.

Always ensure your grow nutrients have trace amounts of Mo available, if you don’t see it on the company MSDS or bottle analysis then it’s not in there!

Monitor pH levels, hydroponics is all about precision so a little mistake early on can cost you dearly at the end. The best pH pens on the market in my opinion are the ranges available from Apera


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