It is undisputed that mowing is an essential part of lawn care. What is less well known is that liming the turf is just as important: without lime, the grasses may not be able to benefit from the nutrients present in the soil or added through fertilization.

Lime changes the pH value of the lawn and is therefore not always appropriate

Table of Contents

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  1. the essentials in brief
  2. apply lime
  3. How much lime to apply
  4. When to lime?
  5. means for liming
  6. Why lime?
  7. Lime or fertilize?
  8. soil survey
  9. soil pH
  10. Lime overdose

    11. the essentials in brief

    • Before applying lime, measure the pH of the soil
    • Lime is applied when the soil is too acidic, i.e. has a pH below 5.5
    • Moss infestation is an indication of acidic soil that needs lime
    • Lawns are best whitened in spring or autumn

    Only if you know why and when your lawn needs lime and how the agent helps it can the green area stay healthy and free of unwanted growth such as moss, sorrel and other weeds. In the following article we provide you with well-founded answers to the most important questions regarding the optimal supply of lime to the lawn.

    What is the best way to apply lime?

    Lawn lime is commercially available either in powder form or as pellets. Lime powder is a white, very fine powder that is simply spread over the lawn. When buying, choose a variety that is ground as finely as possible, as it reacts more quickly with the soil due to the larger surface area. Wear a face mask while applying to avoid inhaling the fine dust. Under no circumstances should lime powder be spread in wind and/or heavy rain. Liming is also not recommended in hot weather or in intense sunlight, as this can burn the turf. Limestone pellets, on the other hand, cause significantly less dirt and are simply distributed evenly over the lawn. After liming - especially if the drought persists - you should water the lawn vigorously so that the calcium carbonate can penetrate the soil and do its job.

    How much lime should I apply?

    How many grams of lime per square meter (g/m2) of lime you need to apply depends on the results of the soil tests carried out previously. These are based on the soil type and the current pH value and thus provide you with the amount that is actually required. Follow these recommendations closely, as allowable amounts can vary significantly depending on soil type. Clay soil, for example, requires much more lime than sandy soil to achieve the same results.

    How much lime should be applied depends on the pH of the soil

    When is the best time to spread the lime?

    Spring, summer, autumn or winter - which month is best for liming the lawn? In principle, you can treat the green area with lime in spring or autumn, but the late summer / autumn months of August and September are considered the best time for this project - after all, the medium has plenty of time for the rather slow chemical reaction until the following spring neutralization of the soil. However, avoid liming in high heat and sub-zero temperatures, as this significantly reduces the effect.

    Which product is best for liming the lawn?

    There are different types of lime that are more or less suitable for lawn care. The most suitable is simple calcium carbonate, which is very mild and gentle and can be applied to almost any soil. With this agent, overliming is also almost impossible, as it is only effective in acidic soils. On the other hand, if the subsoil is neutral, it no longer dissolves as well and is instead gradually broken down by soil organisms. Lawn lime made from calcium carbonate can be identified by the chemical formula CaCO3 printed on the pack. Furthermore, high-quality dolomite lime is also very suitable.

    Quicklime, which is also known as quicklime for a reason, is less suitable. It is normally used as a mortar admixture and is not suitable for lawn care due to its caustic effect on plants. In mixtures for lawn lime you can recognize its use by the chemical symbol CaO - if this is printed on the package, it is better to keep your hands off it. Even special lime mixtures such as magnesium lime or so-called slag lime are only useful in special cases - for example because your lawn already has a magnesium deficiency - and otherwise it's wasted money. Even algae lime, which is sold at a high price, offers no further advantages compared to simple calcium carbonate, even if many manufacturers advertise it flowery.

    Why should you lime the lawn?

    Moss in the lawn indicates acidic soil that can be treated with lime

    Lawns need lime when low soil pH affects nutrient availability. The pH preferences of the various grass species vary, but range from neutral to slightly acidic between 5.8 and 7.2. In the warm season, lawn grasses tolerate a slightly lower pH value, while this should be slightly higher in the cool season. If the pH value deviates too much, the absorption of abundant nutrients is also restricted. Lime restores the balance in soil that is too acidic to bring the pH back to optimal growth levels for the lawn.

    When do you have to sand the lawn?

    Even if the pH value of the soil is in a healthy range, further soil improvement measures may be necessary in addition to liming. This includes, for example, sanding the soil, in which heavy, loamy subsoil is made looser and more permeable by adding sand. Please note that sand also contains lime - depending on the type and variety used - and thus the pH value also changes as a result of sanding.

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    pointer plants

    You can quickly see whether the soil on your lawn is too acidic: in this case, the grasses are crowded out by plants that prefer to grow in acidic soil. For example, the presence of moss or wood sorrel signals that the pH of the soil has long since fallen too low for healthy grass growth. Other warning signs are increased growth of weeds, diseases (which are expressed, for example, in the yellowing of the blades of grass) and the increased occurrence of pests. Above all, grass mites, which prefer to stay in mossy lawns, are a sure sign of this, which is unpleasant for both humans and animals. Therefore, liming also helps
    • against (sour) clover
    • against moss
    • against weeds
    • against grass mites
    • and against fungi

    Be sure to apply the lime first and then any herbicides and insecticides, as a low pH will also reduce the effectiveness of these agents. Another indication of an acidic soil is the fact that even the grasses do not react with the usual or expected healthy and vigorous growth to high-quality lawn fertilizer.

    Clover is an indicator plant for acidic soil

    Should you lime or fertilize first?

    Balanced fertilization is just as much a part of good lawn care as liming. In general, experts advise against applying fertilizer and lime at the same time - only in some cases this can be advisable. Otherwise, it depends on various factors which measure you should take first.

    Basically, the pH value of the soil determines whether it is limed or fertilized first. An example: If this is too low, the lime must first be applied and become effective, otherwise the grass cannot absorb any nutrients. It is therefore also important to clarify this question, which pH value the substrate actually has.

    When do you have to lime first?

    If the soil has a high acid content, it must first be limed and then fertilized after a certain waiting period. Since the process of deacidification is slow, there must be a waiting period of a few weeks between liming and fertilization. However, you can shorten this time by using particularly finely ground lime - this reacts more quickly with the soil, so that fertilization can take place more quickly.

    When should you fertilize first?

    The reverse is the recommendation if you want to sow or overseed a new lawn: In this case, fertilize first and then lime. The reason lies in the germination capacity of the seeds, because they can only germinate and grow into a magnificent lawn if there are sufficient nutrients in the soil. Prepare the area before sowing, fertilize according to recommendations, sow - and then wait about seven to ten days before liming. The waiting time is necessary for the soil to absorb the nutrients from the fertilizer. The lime, in turn, now increases the effectiveness of the same and ensures that the roots of the seedlings can absorb them and benefit from the additional boost.

    In which cases can lime and fertilizer be applied at the same time?

    However, the simultaneous application of lime and fertilizer is possible if the pH value of the soil is already neutral and it is therefore only a matter of maintenance liming. In this case, the task of the lime is to constantly maintain the pH level, while the fertilizer provides the grass with immediately available nutrients. However, you should not apply both together, as this can lead to uneven distribution. First spread the fertilizer on the lawn and only then the lime.

    background

    What is lime?

    Lime is a natural soil conditioner made from ground limestone. The mineral contains the compounds calcium carbonate and magnesium carbonate, which are said to increase the pH of the soil, making it less acidic and more alkaline. Although lime naturally contains important nutrients such as calcium and magnesium, it is not a suitable fertilizer substitute. The main task of lime is to change the pH value of the soil and to balance out the ever-changing acidity of the soil. In this way you improve the availability of plant nutrients.

    Why is a soil test important?

    However, you should not rely solely on a visual diagnosis. A soil test at a government or private institute will provide a more accurate reading of your soil's current pH level, as well as other factors such as soil type. This knowledge is necessary, as this also affects the amount of lime required and any other processing of the soil. Applying unnecessary or excessive amounts of lime can do more harm than good to the lawn. If your soil is too acidic, repeat the test every year until the balance is restored. Established lawns, on the other hand, only need to be checked again every three to four years.

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    Why is soil pH constantly changing?

    Soil pH changes for many reasons, including lime or other products applied. For example, in areas with heavy rainfall, calcium is naturally leached from the soil as rainwater flows through the soil. The pH value drops due to the loss of calcium, so that the subsoil becomes acidic over time. Lime application is a necessity for healthy lawns in these regions. On the other hand, in areas with very little rainfall, no calcium is released, so lawns can even become too alkaline. Lawn care also lowers the pH of the soil. Regular fertilization, proper watering, and increased activity of beneficial soil microorganisms all contribute to the gradual, normal declines in pH.

    How does fertilization affect soil pH?

    Acidic soil contains a lot of hydrogen and becomes more alkaline the more you feed it with a nitrogen-based fertilizer. For this reason, you should definitely avoid over-fertilizing the lawn, as this always leads to acidification of the subsoil. A lot doesn't help much - instead, plant nutrition that is precisely tailored to the specific needs is so important. A thorough soil analysis tells you which nutrients the lawn actually needs and in what quantity.

    Why does mowing the lawn also affect the pH value?

    Regular lawn mowing also leads to acidification of the soil. The reason for this is simply that by mowing you interrupt the natural cycle - and of course this has an impact on the wider environment. The grasses are alkaline and always have a higher pH than the soil on which they grow. In nature, plants eventually die and decompose in the soil, restoring the balance. However, if you mow the grass, this process is interrupted and the ground cannot be leveled.

    What are the consequences for the lawn of an overdose of lime?

    Not only a deficiency, but also an overdose can have serious consequences for the health of the lawn: an excess of calcium carbonate usually results in iron chlorosis, in which the grass eventually suffers from an iron deficiency. As a result, the culms eventually turn yellow or even die. Furthermore, overcalcification leads to chemical burns (especially if quicklime was used!) and, due to the weakening, to an increased incidence of diseases (which show up, for example, in increased growth of fungi) or pests (e.g. ants).

    tips

    Mature garden compost also raises the pH of the soil, which is why some seasoned gardeners swear by homegrown compost rather than lime to neutralize it. Dog urine, on the other hand - as sometimes recommended in forums - is by no means a suitable remedy. Instead, urine damages the turf due to the pungent substances it contains.

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Garden design