Iron is one of the many micro-elements without which the nutrient balance of your plants is unbalanced. The element contributes to photosynthesis, the formation of green leaves and takes an active part in the metabolism. Where there is a lack of iron, growth depression and leaf chlorosis are inevitable. Primarily, however, mosses are taking advantage of the hour in lawns and are spreading extensively. Thus, the specialist trade advocates iron fertilizer so that a velvety green lawn carpet spreads. The other side of the coin is that ferrous sulfate fertilizers are toxic. Read here when you should really sprinkle the fertilizer against moss matting in the lawn.
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Typical symptoms of iron deficiency
If the roots of plants and grasses can no longer absorb iron, this results in leaf chlorosis. This disease is not caused by viruses, bacteria or spores, but is often a result of iron deficiency. The deficit can be identified using these symptoms:
- The young leaves appear pale yellow in color
- The leaf veins stay green, creating a mosaic pattern
- Blades of grass turn yellow
- The leaves on woody plants turn yellow at the tips, while the leaf edges turn brown and dry up
Not only ornamental and fruit trees suffer from iron deficiency. Among the perennials and summer flowers, the most common victims are petunias and other flowering plants, which are also sensitive to lime. As collateral damage as a result of the lack of micronutrients, various types of moss also spread on yellowing lawns, above all the chunky wrinkled brother (Rhytidiadelphus squarrosus). The already weakened noble grasses cannot defend themselves against this invasion, so that there is not much to see of the lush green carpet.
Iron deficiency is only superficial
If your plants and grasses show the classic symptoms of iron deficiency, this does not mean that this micronutrient is missing in the garden soil. In fact, the iron content in normal soil exceeds the needs of your ornamental and useful plants by around 2,000 times. For no other element is the relationship between supply and need for nutrients so positive. Nevertheless, it cannot be denied that your plants and lawn grasses obviously suffer from an acute iron deficiency and that your green carpet is hopelessly matted.
The fact is that iron deficiency chlorosis and moss-covered green spaces are usually not due to an acute deficit in the soil. Rather, the shortage is triggered by insufficient availability of the rich supplies of ferrum. There are various factors that block plant roots in such a way that they can no longer absorb iron, even though it is right on the doorstep. The administration of iron fertilizer consequently does not cure leaf chlorosis, just as it does not permanently rid a green area of moss. Only when you restore the ideal framework conditions can the nutrient balance regain its equilibrium.
Fix the causes of moss growth
Spreading iron fertilizer on moss-covered lawns is like sweeping sand in the desert. The symptom is only combated for a short time. In order to permanently free the green from matting, the causes for the blockage of iron availability should be eliminated. Only when you can rule out the following problems as triggers for the iron deficiency with certainty does the administration of iron fertilizer actually make sense.
- Lack of light due to a location under deciduous trees or in the shade of house walls
- Acid soil due to low pH
- Soil compaction in unity with waterlogging
In the permanent shade under the canopy of deciduous trees, no dense lawn cushion can develop. In these locations, shade-compatible ground cover such as Waldsteinia, star moss or ivy are much more effective as lawn substitutes. Lawn grasses find ideal living conditions in slightly acidic soil with a pH value of 6 to 7. If the value falls below 5, moss-like matting spreads. Instead of sprinkling poisonous iron fertilizer, you raise the pH value again with lime so that the lawn grass regains the upper hand. Incidentally, you cannot create a lawn-compatible pH value with iron fertilizer, as the pH value is also reduced as a side effect. Keep moss growth under control in moist, compacted soil,
Use against moss in the lawn
If the mentioned causes do not apply to your moss-covered lawn, you are dealing with a very rare, real iron deficiency. Please use the garden center or hardware store for special offers for green spaces, as not every iron fertilizer is suitable for this purpose. It is important to note that such products contain iron (II) sulfate, which is classified as highly toxic. How to do it right:
- The best time is in March or April, provided the ground is completely thawed
- Alternatively, choose a day in September with dry, overcast weather
- In preparation, mow down to a stalk height of 3-4 cm
- Wear protective clothing and respiratory protection to avoid coming into contact with the corrosive fertilizer
- Ideally, dissolve the iron fertilizer in water and apply it with the watering can shower or the pressure sprayer
- Cordon off the treated area to prevent children or pets from entering
The most effective effect of iron fertilizer is achieved by allowing the molecules to penetrate directly into the leaves. We therefore recommend buying the fertilizer as a chelate and preparing an appropriate spray solution. The 0.5 percent concentration (5 ml to 1 liter of water) is suitable for the watering can, while the 1 percent concentration (10 ml to 1 liter of water) is recommended for the pressure sprayer. If you decide to spread the grain with the spreader, the fertilized area will then be watered extensively.
Tip : Iron fertilizer is not only very toxic, it also causes irreversible stains on stones. Be sure to cover adjacent, paved paths. In the following days after stepping on the fertilized lawn, do not walk on stone surfaces in order to avoid footprints that can never be removed.
Effect and follow-up treatment
Within 5 to 10 days of application, the effects of iron (II) sulfate will become apparent. The matting turns brown and dies. Then carefully comb out the sward with a rake or rake. You are on the safe side if you scarify the lawn now. Please note that all the combed out parts of the plant are contaminated with toxic iron (II) sulfate and should not be disposed of on the compost.
Tip: Comfrey, nettles, beans, thimble and dandelions act as natural iron collectors in the bed. As underplanting, they bring the iron reserves hidden in the ground to the surface with their roots and make them available to their neighbors.
Causes of iron deficiency in ornamental and useful plants
If your perennials and woody plants show the leaf discolouration typical of chlorosis with the green leaf veins, the iron supply in the soil does not get into the supply lines of the plants. In practice, the following two triggers are primarily responsible for the nutrient blockage. Before you buy expensive iron fertilizer, you should take a close look at these factors:
Excess lime
A large number of popular perennials, summer flowers and ornamental trees depend on slightly acidic soil. These include majestic rhododendrons as well as lavishly blooming petunias. If these plants are continuously watered with normal tap water, an excess of lime builds up in the soil. This causes iron to be fixed and no longer available for the roots, so that leaf chlorosis occurs. If you can diagnose this cause of the apparent iron deficiency, water immediately with collected rainwater or decalcified tap water. By restoring the slightly acidic soil conditions and quickly reducing the excess lime, there is again free access to the iron reserves in the soil.
Compacted substrate with waterlogging
In compacted soil, so much pressure is exerted on the roots that the nutrients can no longer be transported. In combination with waterlogging, the afflicted plants lack iron early on, whereupon the leaves turn yellow. Loosen the substrate thoroughly on a regular basis. Ideally, you work ripe, sifted compost and some sand into the soil, which ensures a fine-crumbly consistency. The root strands recover within a few weeks and reliably perform their vital tasks again.
Application for the short-term supply of iron
It will take a few weeks for the above-mentioned causes of leaf chlorosis due to iron deficiency to be resolved. In order to make up for the deficit in the short term, liquid iron fertilizers are available in specialist shops, such as Ferramin from Neudorff. As part of targeted foliar fertilization, enough iron gets through the pores into the interior of the plant until the way to the stocks in the soil is free again. That is how it goes:
- Pour the liquid fertilizer in 0.3 percent concentration (3 ml to 1 liter of water) into a spray bottle
- Spray onto the top and bottom when the sky is overcast and at temperatures above 15 degrees Celsius
- Never apply liquid iron fertilizer in direct sunlight
Please do not fail to protect yourself against the toxic, corrosive iron (II) sulfate with appropriate clothing and a breathing mask. The treated plants should be kept out of the reach of children and pets.
Tip: To prevent the liquid fertilizer from dripping off the leaves too quickly, add a splash of dish soap to the solution. This measure reduces the surface tension of the water so that the active ingredients adhere longer.
Conclusion
The use of iron fertilizer in the home garden is rightly discussed controversially. As a rule, there is only an apparent iron deficiency when leaf chlorosis develops or lawns are mossed. As this information conveys, the real causes of the lack of iron availability should first be clarified. Lack of light, acidic soil and waterlogging affect your lawn carpet so much that the grasses can no longer defend themselves against the chunky wrinkle brother and other types of moss. On rhododendrons, petunias and other bog plants, changing from hard tap water to soft rainwater can already be the solution to the problem. Iron fertilizers are only used when all of the causes that have been explained fail to trigger the iron deficiency.
