An over-fertilized lawn has many faces. We explain how to recognize the symptoms of overfeeding and what to do about it.
If you take a very close look at your own or your neighbour's lawns, you will quickly see that almost every lawn has a bare spot, discoloration or another surface flaw somewhere. Sometimes the reason for this is simply a failure to choose the right lawn seed mix. Another reason for such lawn damage can be the excessive use of mineral lawn fertilizers. In this article we explain how you can recognize over-fertilization and what you can do to prevent or acutely counteract it. If you are also looking for general information on the subject of lawn fertilization, you will find it in our overview article.
If a purely mineral fertilizer is used to fertilize the lawn, over-fertilization can easily occur. Slight and heavy over-fertilization can be recognized by different characteristics, which we would like to briefly present to you. Then we'll give you tips on how to save your battered lawn.
How do I recognize over-fertilization in the lawn?
What over-fertilization looks like depends on how dramatic the over-fertilization was. In milder cases, nutrient-typical excess symptoms appear on the lawn plants. We have summarized the most important ones in a table here.
| Nutrient | Excess Syndrome |
|---|---|
| Nitrogen (N) | - Excessive, masty growth; brittle, curled or thickly swollen leaves - Susceptibility to frost damage - Dark green coloring - Susceptibility to fungal diseases - Root death - Causes calcium - and magnesium deficiency: growth inhibition, dying off of the leaf tips, reduced root growth, yellowing |
| Phosphate (P) | - No/hardly any symptoms on the plant - "Fixation" in the soil, with very strong over-fertilization also leaching into the groundwater and contamination of natural water bodies |
| Potassium (K) | - Causes calcium deficiency: growth retardation,Die-off of leaf tips |
| Magnesium (M) | - Causes calcium deficiency: growth retardation, leaf tip death |
Slight overfeeding is not too dramatic and does not need to be treated. In the future, however, you should be careful not to distribute too much of the excess nutrient. Or you can rely on a primarily organic lawn fertilizer such as our Plantura organic lawn fertilizer. This makes over-fertilization almost impossible due to the slow conversion of nutrients.
In the case of heavy over-fertilization, the lawn grasses first turn yellow, then brown and finally die off over the entire area. The layman may then speak of "burns", but in fact it is the high concentration of fertilizer s alts in the soil that causes problems for the roots of the lawn.
How do the burns occur in the lawn?
The "burns" are caused by the so-called exosmosis. In order to better understand this term, one should deal a little with the nutrient uptake of plants. Plants actively absorb many of the required nutrient ions into the root hair cells through special channels. This increases the concentration of ions in these cells. As water moves from low ion concentrations to higher ion concentrations, cells filled with nutrient ions attract and absorb water. In this way, the water balances the concentrations in root hair cells and soil. It is said that the water follows the “osmotic gradient”. So plants actively create a kind of suction to absorb water.
This effect is reversed in the case of severe over-fertilization, hence the term "exosmosis": If there are suddenly a large number of nutrient ions outside the root, the concentration of particles is higher there. The osmotic gradient then runs the other way around and the plant roots cannot absorb so many ions that there is a higher concentration in their roots. As a result, the water migrates out of the plant and it can therefore no longer maintain its vital functions. Incidentally, road s alt also causes damage to plants in this way.
Tip: A sufficient amount of spilled petrol or petrol mixture, chain oil from a chainsaw, pesticides or cleaning agents accidentally spilled on the lawn also lead to bald spots. For this reason, devices should only be refueled on paved surfaces and cleaning agents therefore do not belong inthe garden. In our Plantura Shop you will find environmentally friendly alternatives to harmful pesticides.
What can you do to prevent over-fertilization in lawns?
It's already happened: When filling the fertilizer spreader, the sack with the mineral lawn fertilizer tipped over and the contents were spread over half a square meter of lawn. Now you should proceed quickly and thoroughly:
- With gloved hands, remove as much fertilizer from the lawn as possible
- Use a rake to rake as many grains of fertilizer out of the turf
- Water the affected area thoroughly and for a long time - this will dilute the increased nutrient concentration
If you have applied too much fertilizer to your entire lawn, only thorough watering will help. Incidentally, this is actually a basic rule when fertilizing lawns: It is best to only spread fertilizer if rain is forecast for the next day. If this is not the case, the fertilizer must be brought into the soil by watering and diluted.
But if over-fertilization has happened or if a dog has peed a hole in the lawn unnoticed, only repairing the lawn at this point can help. The fast-germinating seeds of Lolium perenne and Festuca rubra as in our Plantura lawn repair now protect the bald spot from unwanted weeds.
It is of course better to take precautions directly, which we would like to recommend to you at this point. Here are some tips to avoid overfeeding:
- It is best to use organic or mostly organic fertilizers. These are implemented slowly, even if they are distributed too generously, over-fertilization cannot occur.
- Our Plantura organic lawn fertilizer and organic autumn lawn fertilizer protect you from over-fertilization.
- Use mineral fertilizers strictly (if at all) according to the dosage recommendations.
- Always leave fertilizer bags on paved surfaces and fill buckets or fertilizer spreaders there.
- Always check the function and adjustment of the fertilizer spreader before use.
- Water after fertilizing or fertilize when rain is forecast.
Fertilize your lawn correctly: tips for correct application
If you use our Plantura organic lawn fertilizer to avoid over-fertilization, proceed as follows:
- Fertilize 2 or 3 times a year
- Mow your lawn fairly short
- Spread 40 to 60 g/m² of our Plantura BioLawn fertilizer by hand or refer to our recommended settings for fertilizer spreaders.
- If you don't have a scale at hand: A water glass with a volume of 0.2 L corresponds to 130 g of our fertilizer. Accordingly, a filled 1 L bucket contains 650 g of our fertilizer
- While our primarily organic fertilizers do not cause over-fertilization, sprinkling will allow the nutrients to take effect more quickly.
Tip: Is your lawn always yellow and dried out in summer? Of course, this does not have to be related to over-fertilization. If your soil is light and sandy and your lawn is in full sun, you may want to think about planting a special dry lawn. Our certified Plantura dry grass, which consists of drought-tolerant grasses, is perfect for this. We are also happy to give you tips on how you can minimize not only frost damage, but also dry damage with the help of a potassium-rich autumn lawn fertilizer such as our Plantura organic autumn lawn fertilizer.
You can find out how to fertilize your lawn in the right amount and thus avoid over-fertilization in our overview article.
And in another special article we have compiled general information about lawn fertilizers for you.
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