Iron Fertilizer: Application & Effect of Ferrous Sulphate

Iron as a nutrient is mainly needed for the formation of enzymes. Here's how to use iron fertilizer and if it's toxic.

Not only humans can suffer from iron deficiency, plants can also lack this trace element. In this case, fertilization with iron is necessary. We see iron deficiency through headaches, fatigue, brittle nails and many other symptoms. But how do we now recognize in our plants whether they lack iron and whether we need to help with some fertilizer? Here we provide you with the answer to this question as well as further information on the subject of iron fertilization.

Before we go into more detail about the use of iron fertilizer and how it works, it is important to understand what properties iron has and why our plants need iron.

Overview of iron properties

Iron is an important part of our lives. It is used as a building material in our homes and even our breakfast juice is enriched with iron. However, we can also find iron on the periodic table under the element symbol Fe, derived from the Latin designation ferrum . Iron is a heavy metal, either as divalent or trivalent iron (Fe²⁺ or Fe³⁺) or in compounds (oxides, s alts) occurs. Only the Fe²⁺ is interesting for our plants, because they can absorb it and feed on it. The Fe³⁺ is not directly available for the plants. The bound iron can be released from the different minerals by weathering. Iron ions are released during this weathering, but several factors affect the availability of iron, such as pH and humidity. Moist soil with a pH of 6 to 6.5 usually contains a large amount of Fe²⁺. If the pH value rises above 6.5 and you also have to contend with drought, this availability decreases more and more. The iron is bound and is then no longer available to the plant.

Why do plants need iron?

The iron is not directComponent of leaf green (chlorophyll) responsible for photosynthesis, but plays an important role in its formation. It acts as a catalyst - which means it accelerates and supports the formation of the leaf green.

Iron has another important role in plant respiration, more precisely in connection with the respiratory chain. The respiratory chain is part of the energy metabolism. Here, energy is generated from the absorbed nutrients - an extremely important process for all living beings. Iron is often also a component of various enzymes that play different roles in metabolism. The Fe³⁺ is not directly available for the plants, because it has to be converted into Fe²⁺ or chelated first in the soil. Plants can only absorb Fe²⁺ or chelated Fe³⁺. Chelates are complexes that can be taken up by plants as whole molecules. The word "chelate" comes from the Greek chele and means something like claw or crab claw - and that also describes what chelates are. At the center of a chelate is an ion, often a heavy metal like iron. Larger organic molecules cling to this and hold it tight. These compounds are very stable, nutrients can be more easily absorbed by the plant as a chelate.

Detect iron deficiency in plants

How does an iron deficiency show up in our plants? One symptom of iron deficiency is leaves turning yellow while the veins of the leaves remain green - this is called chlorosis. These chloroses form first on the young leaves. As the deficiency increases, necrosis (dying tissue) forms from the edge of the leaf. When an iron deficiency occurs, there is also a lack of chlorophyll, protein and energy. Therefore, the growth as well as the yield of the plant decreases. Flowers can also fade in color and remain smaller overall. With an iron deficiency, the roots are usually short and have many short lateral roots. If the iron deficiency is not treated, your plants can even die - but only if the deficiency is severe.

Especially on calcareous soils, iron deficiency is often found, because iron is precipitated there by the calcium carbonate present there. The iron cannot do thismore to be included. Some plants can already show what soil they are growing on - for example, soils on which a lot of coltsfoot, nettles or dandelions grow are often rich in lime. We have also compiled further information on chlorosis for you in a special article here.

Summary of signs of iron deficiency in plants:

• Presence of chlorosis with leaf veins remaining green
• Signs appear on young leaves first
• Necrosis appears later starting from the leaf edge
• Stunted Growth
• Low Yield
• Pale, small flowers
• Occurrence of short roots and many lateral roots

Drought and compaction can also be reasons why the plant cannot absorb iron. It is therefore worth watering the plants properly after a long drought. Waterlogged and compacted soil can also be a hindrance to the iron absorption of the plants. Such soils often inhibit root growth and there is a lack of oxygen or at the same time an excess of carbon dioxide. Mechanical loosening and the incorporation of primarily organic fertilizers such as our Plantura organic fertilizers can put an end to compaction.

Another important factor that triggers iron deficiency is the excess of other heavy metals in the soil. The transport and uptake of iron can be inhibited if there are many ions of chromium, copper, cob alt, zinc, manganese or nickel in the soil. Bark humus can contain a lot of manganese and an excess of zinc in particular can lead to an iron deficiency.

Generally speaking, problems must be expected as soon as the ion balance in the soil is disturbed. The interaction of iron and phosphorus is particularly interesting. When there is a lot of phosphorus in the soil, it is possible for these two nutrients to combine and form ferric phosphate. We know this compound as slug pellets, but it can also form in the soil and thus bind the nutrients.

Here we have briefly listed the iron deficiency triggers again:

• Too high pH
• Waterlogging
• Drought
• Inhibited root growth
• Imbalance and excess of other nutrients
• High Phosphorus

Use iron fertilizer correctly

If your plants are now affected by an iron deficiency, there are various ways of supplying them with it. ThereSince iron can be absorbed via the roots and the leaves, you have several possible uses.

Iron Foliar Fertilization

Iron can not only be fertilized over the soil, but also as foliar fertilization. The advantage of foliar fertilization is that it takes effect very quickly. Since the fertilizer is not introduced into the soil, it cannot be washed out and is effective despite dry soil. However, foliar fertilization can only be used at a low concentration to avoid damage to the leaves.

This form of fertilization also has to be used more frequently and the fertilizers are unfortunately a bit more expensive than other iron fertilizers. It is also possible to use iron fertilizer regularly as a preventive measure and thus counteract deficiency symptoms. But always stick to the product description and the recommended doses. When using iron fertilizers, it is also important not to apply them in blazing sun and at temperatures above 25 °C - this can damage the plants.

Iron fertilizer in the irrigation water

You can also add iron with the irrigation water. To do this, dissolve the iron fertilizer in the irrigation water according to the product description and add it to the plants. In the irrigation water, an amount of 1 to 2 mg iron per liter of water is sufficient for proper iron fertilization. Then rinse the watering can thoroughly to remove any product residue. Also, be careful not to stain the floor or your clothes with the iron fertilizer. This results in unsightly rust stains that are either difficult or impossible to remove.

Which plants are often affected by iron deficiency?

To put it simply, cultures that consume a lot are often affected. Ornamental plants such as roses (Rosa), hydrangeas (Hydrangea), magnolias (Magnolia) and rhododendrons are particularly suffering often below. Fertilizers for rhododendrons and roses often contain a small amount of iron to prevent chlorosis due to iron deficiency. Also heavy consumers of vegetables such as tomatoes (Solanum lycopersicum), cucumbers (Cucumis sativus) and peppers (Capsicum ) are struggling with the lack of iron.

In fruit, one often finds one in berries, apples (Malus) and quinces (Cydonia oblonga). The flower lovers belowThose who like to have petunias (Petunia) on the balcony will certainly have been confronted with an iron deficiency at some point. If chlorosis occurs in petunias, it is usually due to an iron deficiency. You can also find out more about chlorosis in petunias here.

Iron fertilizer for lawns and against moss

Even your favorite green lawn can suffer from iron deficiency. This is mostly caused by the soil conditions. Some soils contain more iron, others less. But to be absolutely sure, you can carry out a soil test. One way of using iron fertilizer on the lawn is to combat unwanted moss. If your lawn is heavily covered with moss, you can treat the damp moss with iron fertilizer. Before doing so, you should mow the lawn to a length of about 3 to 4 cm and then treat the moss with iron fertilizer (ferrous (II) sulphate). Iron fertilizer can be used either as granules or, as already described, mixed into the irrigation water as a liquid fertilizer. The application should be done in spring in March or April, if the ground has already completely thawed. The moss then dies off after about two weeks and turns brownish to black. You can then simply remove the moss with a rake or rake. It is particularly important that you fill in the gaps left by the moss.

After removal, sow grass again to prevent other weeds or moss from settling. If you remove this moss in the spring, this is ideal so that the reseeding can take root. Do not walk on the lawn for about two weeks after applying iron fertilizers. Also, keep your pets away from lawns - they could cause poisoning. You can find out what else you can do to prevent moss in your lawn here in our special article.

We recommend always providing your lawn with sufficient nutrients and using primarily organic long-term fertilizers such as our Plantura organic lawn fertilizer. This not only makes your lawn fit and lush green, but also protects the soil and you can always step on your lawn again immediately after fertilization. You can find more information about our organic lawn fertilizer here.

Iron fertilizer for aquariums

Aquarium plants also need nutrients, because if the plants show chlorosis, they too lack iron. ThatAn iron deficiency in the aquarium is not that rare, as can be seen from the fact that the first commercially available aquarium fertilizer was iron fertilizer. A general quantity recommendation cannot be given for the application. Each aquarium is individual in terms of filling quantity, filter systems, stocking, feeding and planting. An optimal iron content in an aquarium is 0.03 to 0.1 mg/l. This can be easily checked with test strips from the pet shop. Another indicator of sufficient iron content is the growth of duckweed. If you have duckweed in the aquarium and enough iron, then the lentils will reproduce well. If there is a lack of iron, the duckweed will stop growing. Unfortunately, fertilization in the aquarium - no matter which nutrient is involved - is often associated with the formation of algae. You should therefore be very careful with the dosage and rather fertilize a little less than too much.

Is iron fertilizer toxic?

In general, iron fertilizers are toxic and you should always avoid physical contact with these fertilizers. Wash your hands thoroughly if you have come into contact with it. If you have symptoms after coming into contact with iron fertilizers, you should definitely consult a doctor.

But it's not just the toxicity that needs to be considered, but also the unsightly stains that the iron fertilizer could leave on your floor or other objects. The rust stains are usually difficult or impossible to remove. Also, be careful with your clothing. It would be a shame for your favorite pair of trousers if they got ugly stains on them.

Buy Iron Fertilizer

Iron fertilizers have a different composition depending on the product. As a rule, however, they always contain the nutrients nitrogen and iron, which are marked with the abbreviations N and Fe. We recommend that you only use iron fertilizer when absolutely necessary. Nutrient deficiencies can often be prevented. For example, our primarily organic Plantura long-term organic hydrangea fertilizer contains a small amount of iron to prevent iron deficiency in hydrangeas from the outset.

Make iron fertilizer yourself

If you don't want to buy iron fertilizer, you have another option: making it yourself. This protects your wallet and of course the environment. Because plants absorb iron as an essential nutrient element, it is naturally invegetable waste, bokashi or compost. Plant material with a high iron content such as spinach, chickpeas, lentils or kidney beans are particularly suitable for producing iron-rich fertilizer. Because the bivalent iron, which is more readily available to plants, is also primarily present in the compost only at a low pH value, it can be mixed with lemon juice or orange juice before use as fertilizer.

An old trick works in a similar way, with which our body should be supplied with iron. Iron nails stuck in an apple oxidize as a result of contact with malic acid. Mixing the crushed apple slices with the potting soil also provides easily plant-available iron. But there's an even easier way: Many plants have such effective tactics of their own for extracting iron from the soil that just sticking iron nails into the potting soil can be enough. When planting - especially in the tub - mixing in plenty of yellow sand can also prevent iron deficiency. Because the yellowing of the sand comes from adhering iron oxides. Another very effective source of iron is blood meal, which can be purchased or slaughtered yourself.

Anyone who has to struggle with moss in their lawn often resorts to iron fertilizer. In our special article on iron fertilizer for lawns you will find everything you need to know about the application and alternatives.