Lime fertilizer is an important material in the garden because it counteracts acidification of the garden soil and thus ensures that your plants can always absorb enough nutrients.
There are different types of lime, but the most suitable for the hobby and home garden is the versatile garden lime.
What is garden lime?
Basically, lime is a form of the chemical element calcium (Ca), which is one of the most important mineral building blocks of humans, animals and plants. Bones and teeth consist largely of calcium, while the mineral is an elementary component of the cell walls of plants.
In nature, calcium occurs in various types of rock and sediments, mostly in its form as calcium carbonate (CaCO3, also known as carbonate of lime). This raw material is also the basis of most lime fertilizers. Limestone is usually obtained from so-called limestone deposits, which are sediment deposits from the primordial seas.
Many millions of years ago, the calcareous remains of sea creatures such as snails, mussels, crabs, and others formed the basis of these rock layers. Limestone today makes up a large part of the earth’s crust and serves as an important raw material for all kinds of purposes in industry, house, and garden.
Garden lime against moss
Moss loves acidic soil. If you have a lot of moss in your lawn, this is a sure sign that your soil is acidic. Garden lime can help here because it is alkaline and therefore raises the pH value in the soil.
The lime is best applied in the spring and worked into the soil with a scarifier. Scarifying also brings oxygen into the soil, which moss also hates.
What do you need garden lime for?
Every soil naturally has a different pH value, which is a measure of the amount of hydrogen present in the soil. The pH value is shown on a scale between 0 and 14, with neutral soil having a value of 7.
Acidic soils lie below, alkaline (also called basic) above. Most plants thrive best at values between 6 and 7, although there are of course also pronounced acid lovers (moor bed plants) or sand plants.
The plants have their own preferences in this regard, which should be taken into account when choosing a location as well as when fertilizing and liming.
However, the pH value of the soil is not static but can be influenced both unfavorably and favorably. Mowing the lawn and harvesting the berries from the vegetable patch naturally leads to slow acidification, which must be counteracted by targeted liming.
Over-fertilization of the soil with nitrogen-based fertilizers also leads to over-acidification. If the pH of the soil is too acidic, this has many disadvantages for the plants:
- Nutrient Availability: Plants cannot absorb vital nutrients such as nitrogen, phosphorus, and potassium in acidic soil. Growth is inhibited.
- Microorganism activity: Bacteria and fungi cannot break down organic matter under acidic soil conditions, so the nutrient cycle in the soil breaks down.
- Aluminum poisoning: Aluminum dissolves at low pH levels, which restricts root growth and thus the availability of nutrients and water.
Liming counteracts acidification and thus deficiency symptoms.
When does the floor need to be whitewashed?
Garden lime is a tried and tested means of soil improvement, as it supplies the plants with calcium and also makes other nutrients available in the soil. At the same time, the pH value in the soil is raised, so that liming counteracts acidification.
Advantages of garden lime:
- raises the pH of the soil and neutralizes acidity
- supplies plants with lime
- improves the availability of nutrients
- improves the soil structure, creates fine-grained soil
- this is important for the plants to hold themselves in the soil and for their nutrient uptake
- promotes the activity of soil organisms
- strengthens the resistance of plants to diseases
- impedes the growth of many acid-loving weeds and mosses
However, garden lime not only has advantages, but also tangible disadvantages. These occur when the agent is used incorrectly or excessively and reverse the positive effects of liming.
At the same time, an oversupply of lime leads to a faster breakdown of the humus layer, which initially makes more nutrients available – but in the long run, leaches the soil.
Not all plants like lime
When is the right time to apply lime?
Garden lime should be applied in either early spring or fall, with fall being preferred. The slow-acting lime fertilizer then has enough time over the winter months to take effect.
Finally, in the spring, you give your plants a starter fertilization, which leads to healthier and faster growth due to the better availability. Never apply lime fertilizer at the same time as nitrogenous fertilizers, as this will reduce the nitrogen content.
Apply the garden lime either freehand or with the help of a special spreader. The latter helps to distribute it more evenly over larger areas. Pay attention to a broad and even distribution, and these instructions should also be followed:
- lime on dry soil
- do not sprinkle over plant parts, but apply directly to the ground
- Contact with plant parts can lead to burns on leaves etc
- Incorporate deeply into beds and borders
- Then water the lawn well
Lime Fertilizers Types?
Garden lime is commercially available under very different names, with more or less similar basic components being hidden behind the various brand names.
However, not every type of lime is suitable for every soil. The following table clearly shows which type of lime should be used on which soil:
|soil type||characteristics||Lime type||characteristics|
|rich in humus||dead and decomposed organic material, rich in nutrients, finely crumbly, dark||carbonate of lime||natural calcium carbonate, gentle and effective for a long time|
|rich in humus||dead and decomposed organic material, rich in nutrients, finely crumbly, dark||algae lime||natural lime fertilizer from red algae, contains additional nutrients, gentle and long-lasting|
|easy to moderate||sandy to loamy||garden lime||natural calcium carbonate, versatile|
|sandy||sandy, very light, permeable, poor in nutrients||lime marl||contains calcium carbonate and clay, improves soil quality in the long term|
Carbonate of Lime
This is lime fertilizer that is obtained from natural lime deposits. These include, for example, these types:
- chalkstone or chalk lime
- lime marl
- dolomite lime
These rocks consist mainly of calcium carbonate, which is also known as carbonate of lime. The ground limestone is particularly suitable for the garden, as it only dissolves slowly and is therefore as gentle as it is long-lasting.
Dolomitic lime is a type of lime that also contains magnesium and is therefore particularly suitable for plants with a higher magnesium content.
Make sure not to use lime fertilizers with a magnesium content of more than ten percent for regular liming. Otherwise, there will be an oversupply.
Algae lime is obtained from the dead deposits of the red algae and is therefore also one of the natural types of lime. The agent contains around 70 percent calcium carbonate, up to ten percent magnesium, and, in contrast to other lime fertilizers, other trace elements.
This natural lime fertilizer makes a significant contribution to improving sandy soils, as the clay it contains improves its storage capacity. With regular use, water and nutrients no longer “just run through” but remain in the soil and can be absorbed by the plants. High-quality lime marl consists of 60 to 70 percent calcium carbonate and 30 to 40 percent clay.
Garden lime is not a type of rock, but the general name for various types of lime fertilizer. As a rule, it is ground natural lime with or without magnesium content. Sometimes garden lime also contains additives such as additional fertilizers or weed killers.
Garden lime is difficult to dissolve, which is why its effect only unfolds slowly and gently.
Quicklime or unslaked lime (calcium oxide) was still widely used in home gardens a few decades ago but is now only found in agriculture. The substance can be mixed with water, where it reacts to form calcium hydroxide – the so-called slaked lime.
Both forms are fast-acting, but also highly aggressive. They burn the skin and mucous membranes, and improper use can cause serious damage to plants and the environment. These agents are absolutely not recommended for garden liming!
Is there a difference between lawn lime and garden lime?
Many commercially available types of lawn lime are also mixed with long-term fertilizers for healthy grass growth, which is not always sensible. Depending on the pH of the soil, fertilization and liming should not be done at the same time.
- high pH value: lime first (best in autumn), fertilize in spring
- Laying a new lawn: fertilize as well as lime when sowing grass seed
- Neutral pH value: Liming and fertilizing can be carried out at the same time, even with maintenance liming
Test the lime content of the soil
For this reason, you should always check the pH value of your garden soil before applying lime fertilizer. To do this, you can take soil samples and send them to a specialized laboratory (and get exact fertilizer recommendations back at the same time), but you can also carry out the test at home.
For this purpose, there are special lime tester sets in specialist shops that you can use even without basic chemical knowledge. The disadvantage of home use, however, is that you will not receive any fertilization or liming recommendations. Instead, you have to calculate the correct amount of lime yourself.
Certain plants – so-called indicator plants – also give you a clear indication of whether your soil is more acidic or alkaline. These plants thrive in very specific soil conditions and thus show the pH level at their location without any testing.
The table below lists some of the most common species in the home garden.
|These indicator plants indicate acidic soil||These indicator plants like lime|
|field dog chamomile||chicory|
Deficiency symptoms are an indication of hyperacidity
Yellowed leaves, dried shoot tips, or brownish spots on the flesh of the fruit: all of these deficiency symptoms often indicate that the soil is overly acidic. But not only, because these phenomena also occur in the event of waterlogging or a general lack of nutrients (e.g. as a result of insufficient fertilization).
frequently asked Questions
Does lime also help against snails?
In fact, a ring of carbonate of lime or garden lime around an endangered plant can protect it from voracious slugs. The animals generally avoid crawling over the material, which is sharp and drying for them.
Is lime actually toxic to dogs?
Do not let your pets – not only dogs but also cats and rodents such as guinea pigs and rabbits as well as turtles – run across freshly limed soil or lawns. The agent may have a corrosive effect and can thus lead to injuries. If limed grass is also eaten, poisoning is very likely, especially in small animals.
Although eggshells are calcareous, they are not suitable as a substitute for garden lime. Nevertheless, you can use them as an inexpensive fertilizer for indoor and balcony plants and, of course, in the garden.
To do this, soak crushed eggshells in tap water for a few days and then water your plants with them. Calculate two to three eggshells per liter of water.