A molybdenum deficiency initially resembles a nitrogen deficiency. The oldest leaves at the bottom will turn yellow and might get dark spots. A molybdenum deficiency is recognised by a unique orange, red or pink colouring around the edges of the leaves. This colour may spread to the centre of the leaf.
How do you recognise a molybdenum deficiency?
- Looks like a nitrogen deficiency at first.
- Yellowing and possible dark spots on the oldest, lowest leaves.
- Unique orange, red or pink colouring at the edges of the leaves.
- Twisted young leaves.
What is the (possible) cause?
- The pH value of the soil or substrate is too low.
- There likely is enough molybdenum available in the soil, but the roots are unable to absorb it.