Iron Deficiency Treatment for Plants

Iron is an essential micro-nutrient for plants and plays a crucial role in several important processes within the plant. Iron is necessary for chlorophyll production, which is responsible for the plant's green pigmentation and its ability to carry out photosynthesis. Without sufficient iron, plants may exhibit pale yellowing leaves, known as chlorosis, and have stunted or slow growth.

As iron is needed to produce chlorophyll, iron deficient plants have pale or yellow leaves, often with green veins. This is called interveinal chlorosis. Young leaves may appear to be bleached. As iron deficiency progresses, leaves can develop brown spots. And despite being fertilised with a general fertiliser, iron deficient plants may also have stunted growth.

Symptoms of iron deficiency can sometimes be confused with manganese deficiency which can also lead to yellowing between the veins of the youngest leaves, particularly in spring. Similar to iron deficiency, the veins remain green. To help correct manganese deficiency, which can be common on citrus trees, apply Yates Citrus Cure Zinc & Manganese Chelate.

For plants that exhibit overall pale or yellow leaves, with no green veins, this could indicate a nitrogen deficiency. Nitrogen is a vital nutrient that contributes to plant growth and photosynthesis. Regularly applying a nitrogen-rich fertiliser, like Yates Thrive All Purpose Soluble Fertiliser, will help correct nitrogen deficiency and keep plants healthy.

Iron deficiency can be caused by several factors:

• Lack of iron in the soil. This may be due to the parent soil minerals having low levels of iron, the iron being leached from the soil due to high rainfall or watering or the soil being overly wet. 
• Alkaline soils (soils with pH above 7.5) can make it difficult for plants to access iron and lead to iron chlorosis (also known as lime-induced chlorosis). Acid-loving plants, such as Azaleas, Camellias, Blueberries and Rhododendrons are particularly susceptible to iron deficiency when growing in alkaline soils. Alkaline waterlogged soil can exacerbate iron deficiency. 

Plant growth can be assisted in iron deficient soils by applying Yates Leaf Greener Iron Chelate. This liquid form of chelated iron is most commonly applied as a foliar spray. It is fast acting and helps correct iron deficiencies. 

In alkaline soils, Yates Leaf Greener Iron Chelate can also be used to supply iron to plants. However, it is best to correct the pH of the soil, bringing it closer to neutral or slightly acid and improve iron availability.

First, test the pH of the soil using a kit that can be purchased from a hardware store or garden centre. If your soil has a pH of 7.5 and above, then you will need to lower or acidify it. This will help improve the availability of iron to plants. An effective way to lower soil pH is to apply Yates Sulfur Soil Improver Granules. These granules contain sulfur, helping to lower soil pH, plus bentonite, which improves soil structure and water retention. These granules are easy to handle and apply and are less messy and dusty than traditional sulfur powders. Reapply every four weeks until the required soil pH is achieved. The added benefit of creating a more neutral soil pH is that other nutrient deficiencies, such as manganese, boron, copper and zinc, will also be reduced. 

Another way to lower the soil pH (make it more acidic) is to use Yates Soil Acidifier Liquid Sulfur, which contains elemental sulfur (S). Soil bacteria convert the sulfur to sulfuric acid and thereby, help lower the soil pH. This is highly dependent on soil bacteria, so it's best to apply when conditions are warm and soil microorganisms are more active. For best results, apply every 4 weeks until the desired pH is achieved. Take care not to overapply – this will not make the process faster and it can lead to issues with sulfur toxicity and cause the pH to drop too low.