Add Lime to The Soil of Your Garden or Garden Beds

Lime is strictly defined as a white corrosive alkaline substance - quicklime; Chemically, calcium oxide (CaO); Made by heating chalk or limestone. But in horticulture, lime refers to any calcium-containing material that corrects soil acidity. The following content also has some reference value for raised garden beds.

Why use lime

The main reason for using lime is to reduce the acidity of acidic soil, or in other words, sweeten the soil. Few plants will grow well in very acidic soils, mainly because their intake of plant-based foods is reduced; Phosphates, in particular, are "locked" in acidic soils. Calcium is often deficient in very acidic soils.

On the other hand, the release of aluminum and manganese is usually so large that they can poison many plants. Tomatoes, beans and brassica are particularly sensitive in this regard.

raised garden beds

Lime promotes soil life

Bacteria that convert ammonium salts to nitrates β€” one of the necessary steps before plants can use nitrogenous foods β€” work little or no way in very acidic soils. The organisms responsible for fixing nitrogen in the roots of peas, beans and other legumes are most beneficial when the soil lime is good, which is why peas do not thrive in really acidic soils. But azaleas can get very sick and even die in the soil of peas. Earthworms also thrive in lime-good soils; They form channels in the soil, improve drainage of clay and compacted lawns (we know that worms are ugly, but the benefits of worms in improving drainage outweigh their harms).

Lime improved cultivation

Many clays, when limeped regularly, become more porous, allowing rainwater to drain faster, allowing you to reach the ground earlier in spring. Very viscous clays can be healed by means of lime, but not all clays react because some clays are naturally calcareous. Lime has little effect on tillage of sandy and loamy soils.

Lime controls some pests and diseases

Brassica lichen root disease is prevalent in acidic soils and can usually be controlled by lime, but it takes two or three years to fully function. Lime does not encourage slugs, leather jackets or nematodes and several other soil pests.

How to tell if the soil needs lime

The presence of spurs, sheep sorrel, corn marigolds, and other weeds that thrive in acidic soils usually indicates the need for lime, but these weeds are not very reliable indicators because they continue to grow in the lime's soil for some time. If you see azaleas and blue hydrangeas growing well in nearby gardens or raised garden beds, it's fairly safe to assume your soil is naturally acidic. However, the only reliable way to determine if the soil is acidic or alkaline is to perform a soil test on lime. An old-fashioned way to tell if a soil is calcareous is to pour some dilute hydrochloric acid over the soil to see if it hisses, but that doesn't help much; If the soil is rich in calcium carbonate, it reacts with the added acid and carbon dioxide gas, resulting in a hissing sound. However, the lack of hissing is not a reliable indicator of the need for lime, of course, the test does not know the amount of lime required to correct the acidity in acidic soils.

raised garden bed

How to test lime

The easiest do-it-yourself approach is to buy some indicator paper from your garden supply center and take a sample of the soil in the garden or in your raised garden bed. If the soil is dry, moisten it in a dish with water (distilled if possible), but do not let it run. After half an hour, place a 2 cm strip of test strip on wet soil and the other half on the side of the saucer. After 5 minutes, compare the color of the paper with the color panel on the chart, which is sold with the paper.

While we're talking about old-fashioned but useful techniques, let's take a quick look at the methods for determining garden soil texture instead of acidity or alkalinity. Take a scoop of soil samples and shake well in a glass or other clear water container. Then set it aside and settle down. If you have reason to believe that your soil is different in different parts of the garden, perform the same test using multiple samples taken from elsewhere.

After some time, you will see that many identified layers appear. The stone is on the floor or bottom of the container, on top of which is a layer of sand. Loam with a certain proportion of sand forms the next layer. The clay content, light and powdery, will dissolve and will only color the water, remaining in suspension for a long time. Finally, humus will tend to float on the surface of the water, or perhaps some will sink to form the top layer if shaken violently.

raised garden beds

With this simple approach, you can make a very fair assessment of the capabilities and requirements of the soil in the raised garden bed.

For peat soils and soils that are naturally rich in humus, you will have to increase the amount of lime further. In fact, it is almost impossible to correct the acidity of some of them; Some Finnish soils are very acidic, and even with the application of large amounts of lime, the soil still shows an acid reaction the following year. So all you can hope for is correct the worst acidity.
Fortunately, such soils are rare. If you feel that the whole job of determining lime needs is too complicated and you know that your soil is acidic, a good general rule is to apply 0.3 kg of hydrated lime per square meter (square yards) on sandy or loamy soils and 0.8 kg per square meter (square yards) on clay or peat soils. On the other hand, you may be an accurate gardener and therefore want to know exactly how much lime you need. For you, there is a special lime requirements test kit that can provide more accurate guidance for correcting the acidity of the soil in a garden or garden beds or the amount of lime needed to potentially raise the pH of a particular plant's potted compost.