Skip to content
Magnesium Deficiency

Magnesium Deficiency

A magnesium deficiency first becomes visible at the oldest leaves. Here small rust coloured or cloudy yellow spots will appear. Dead spots may also occur and leaf tips will curl up. As the spots spread, the leaves will turn more yellow. This causes the plant to look more and more tattered. In this stage you'll also see colouring of the young leaves and a decrease in fruit production.

How do you recognise a magnesium deficiency?

  • Yellow-green to yellow discolouring between the veins.
  • Yellowing and brown spots on older leaves.
  • The plant will create less fruits and flowers.
  • The stems of leaves will turn purple.
  • The tips of the leaves curl up.
an overview shot of some leaves and a stem that are suffering from a magnesium deficiency

What is the (possible) cause?

  • The pH value of the soil or substrate is too low.
  • The root environment is too cold or too wet.
  • The root system of your plant is underdeveloped.
  • The EC value of your soil or substrate is too high.
  • There is too much nitrogen, potassium and calcium in the soil or substrate.

How can you prevent it?

Choose a magnesium rich potting soil for your plant to grow in. You can mix a handful of magnesium granules through the soil to achieve this. The soil temperature is also important: keep this around 22°C. Use one of our basic nutrients (like Dutch Pro Soil or Hydro/Coco Grow or Bloom) to reduce the likelihood of a deficiency. Also keep abiotic factors in mind. These include temperature, light intensity, acidity, amount of moisture and wind strength.

How can you cure it?

The best way to cure a magnesium deficiency is to simply give more magnesium. Don't give this directly through the soil however, as this may cause a calcium deficiency in your plant. Instead, spray foliar feed like Dutch Pro Cal/Mag. Do you think the problem is caused by an incorrect EC or pH value? Then we advise flushing your system with clean, pH-controlled water.

What does magnesium do for the plant?

Magnesium is very important for photosynthesis of the plant, since it is a building block of chlorophyll. This means it helps your plant grow. Many enzymes also require magnesium to fulfil their function.
Previous article Iron Deficiency
Next article Low Level of Potassium in Leaves: Symptoms are Shown During Flowering