Nutrients deficiency can lead to the yellowing of the plant leaves which can consequently fall off. Early detection of the problem and prompt course of actions will help to reverse this process, so the plants are healthy again. Among calcium, nitrogen, zinc, potassium and magnesium deficiencies, iron is probably the most common nutrient deficiency in plants.
So, what causes iron deficiency in plants?
#1 – Iron deficiency in plants is not necessarily caused by the lack of iron in the soil, the plant might not be able to absorb nutrients. Plants absorb nutrients through the roots. To absorb the nutrients from the soil plants need water. So, you need to make sure that plants are getting enough and not too much water.
Also, the soil should be well drained and it is worth having a drainage system in place. Poor drainage leads to waterlogged roots. Alternatively, the roots can be damaged or compacted.
#2 – Iron deficiency can be caused by high levels of nitrogen, zinc, manganese and molybdenum in the soil.
#3 – Soil pH can have an impact on the nutrients absorption. Very acid or alkaline conditions make the nutrients unavailable for the roots to absorb them from the soil.
What happens if a plant doesn’t get enough iron?
Iron is a key component in the production of chlorophyll, a pigment found in the chloroplasts of plants. It is not only responsible for the green color of the leaves but is crucial in photosynthesis because it is allowing plants to absorb the energy from sun.
So, if the plant doesn’t get enough iron, the leaves will turn yellow and then brown, and eventually will fall off. Next, it can happen that plant has little or no ability to produce carbohydrates in photosynthesis and can die.
What are the symptoms of iron deficiency in plants?
The most significant symptom of iron deficiency in plants is chlorosis also know as yellowing. If the plant lacks iron, the area between the veins of the leaves turns yellow and the veins are dark green and small.
Also, if the plant is in iron deficiency, younger leaves will be affected because iron is immobile in plants. Other signs and symptoms of iron deficiency in plants include stunted growth and poor flowering or fruiting.
What to use for iron deficiency in plants?
Use iron fertilizers to the soil for iron deficiency in plants. To treat iron deficiency use chelated iron fertilizers. Chelate is an organic compound that keeps iron in the plant-available form. The most common chelated iron fertilizers are Fe-DTPA, Fe-EDDHA and Fe-EDTA.
Although Fe-EDTA is only effective in soil up to pH 7.1, it can be used as a foliar spray. In a meantime Fe-EDDHA is more efficient in highly alkaline conditions (pH up to 9).
As an addition you can use spraying fertilizer. The most common and cost-effective option is iron sulfate also known as ferrous sulfate (FeSO4.2H2O). Simply mix 1 to 2 oz of iron sulfate with 1 gallon of water. On the other hand, you can make use chalated iron such as Fe-EDTA for foliar application but it is more expensive and has little advantage.
However, it is not recommended to use non-chelated iron fertilizers like iron sulfate on high pH soils as this iron doesn’t come in the plant-available state.
What is a good source of iron for plants?
Natural treatment of iron deficiency and a good source of iron for plants is manure. Manure helps to keep iron in the plant-available state and increases the levels of soil organic matter.
How to treat iron deficiency in plants?
Step 1 – Determine the pH level of the soil with the soil pH meter. For example, to grow tomatoes the pH should be around 6.0 to 6.8. 7.0 is neutral on the pH scale but tomatoes like slightly acid soil. So, you need to avoid growing acid loving plants on the lime soil.
Step 2 – Lower the soil pH to under 7. Add some compost or manure but make sure when buying one to double check the label as most of them have pH in the range of 7 – 8.
Step 3 – Reduce the amount of phosphorus in the soil.
Step 4 – Apply chelated iron into the top two inches of the soil. Add it in the evening to avoid photodegradation. Depending on the soil and plant properties, you might need to apply it several times during the growing season.
Step 5 – Spray ferrous sulfate solution directly on the plant foliage. To prepare the solution you need to mix 1 to 2 oz of iron sulfate in 1 gallon of water. You can also add a few drops of natural soap to the solution. It helps to wet the leaves and improves penetration.
Spray foliar spray on the leaves in the evenings when it is cool to avoid burning tissue of the leaf. Repeat the treatment every few weeks but don’t make a stronger solution than recommended.
