How do stones improve soil drainage?

Soil improvement

What makes a good garden soil?

When it comes to soil, the right mix of ingredients is important to enable the plants to grow as well as possible. A good garden soil has a crumbly structure, stores enough water and is still well ventilated. It holds enough nutrients for the plants and is easy to work with. All of these properties are created through the interplay of sand, loam, clay and humus in the soil. Unfortunately, not all floors in our gardens have the desired properties. By adding specific additives in a targeted manner, hobby gardeners can improve their soil in such a way that it approaches its ideal state.

Determination of the soil type

First of all, you need to determine the type of soil in your garden. Take a small handful of soil and shape it into a ball in the palms of your hands. Then try to roll a "sausage" out of the ball. How does the earth behave?

  • The earth has a grainy texture and crumbles when pressed together, a "sausage" cannot be shaped, then it is one Sandy soil.
  • The earth feels smooth and the ball holds together well. The earth doesn't stick to your hands, then you have Clay soil in the hand.
  • The earth feels smooth and sticky, the ball holds together very well. A "sausage" is easy to shape and the earth gets a shiny surface, if you rub it, then your garden consists for the most part Clay soil.

Soil structure

In addition to humus, animal and plant organisms, the soil consists of solid mineral particles. They usually come from the so-called parent rock, which is located under the fertile soil. It is not necessarily a solid rock, because sand, clay and even peat are also called this in soil science. This parent rock is essentially responsible for the type of soil that is created by weathering. The arrangement and size of the mineral parts form the soil structure and thus also the cavities in the subsoil. These gaps in the soil, the soil pores, are filled with water or air. The air / water ratio in the earth changes depending on the size of the soil pores.

sand has a coarse grain size with individual soil particles between 2 and 0.06 millimeters in diameter. The cavities are particularly large and the rainwater penetrates the soil very well. However, sand can only store water poorly and it quickly seeps into the subsoil. The soil pores are filled with air after the water has drained.

Silt has a grain size of 0.06 and 0.002 millimeters. Here the ratio between water and air is balanced, as the soil pores are smaller than in the sandy soil. Excess water can seep away well, while a certain amount of water is retained and ensures a good supply of plants. Sufficient pores remain filled with air.

Clay particles have the smallest grain size with a diameter of less than 0.002 millimeters. The pores of a clay floor are extremely fine and hold water very well. It is difficult for excess water to run off and the proportion of air in the cavities is very low.

Soil type: light soil

Sandy soils are popularly referred to as light soils because they are easy to work. Rainwater drains off well and there is no waterlogging. Since sandy soil dries quickly, it can be worked almost all year round. However, this also means that it tends to dry out, especially in the summer months. The large soil pores ensure a good air supply to the roots and allow the soil to warm up quickly in spring. However, light, humus-poor soil can only store the nutrients supplied by mineral fertilizers to a limited extent.

Soil improvement for light sandy soils

Organic material such as ripe compost should be worked into the soil every spring. It improves the sandy soil's ability to hold water and nutrients. You should also sow green manure on fallow plots in the vegetable garden or on new building plots. The plants also add organic material to the soil through their green and root matter. After mowing, you can leave the plants on the area if it is not used for other purposes. The organic mulch layer reduces the evaporation of the soil water and protects against strong temperature fluctuations - both promote the life of the soil.

Test the pH of your soil every three years and lime it in the spring if it is below 5.5. Also, promote the earth's ability to store nutrients by spreading materials to improve water retention such as perlite or rock flour made from ground clay such as bentonite and incorporating them lightly with a cultivator.

Soil type: Heavy soil

The term heavy soil also indicates the workability of the soil and stands for loam or clay soil. Heavy soil stores rainwater very well because of its high proportion of fine pores. However, this tends to lead to waterlogging and a lack of air. In spring, heavy soil stays cold for a long time, so that plant growth begins relatively late. As soon as the soil is no longer too wet, it can be dug up or planted. If the water content is too low, on the other hand, cracks form quickly and the hard earth can hardly be worked on. Because the optimal cultivation period is very short, heavy soil is also called minute soil in agriculture. The poorly seeping water easily leads to waterlogging on soils with a high clay content. Therefore, the structure of such floors must be improved with suitable materials. Again, perlite helps improve the soil as it not only stores water but also aerates the soil. Biochar can also be used to improve heavy soils.

Soil improvement for heavy loam and clay soils

It is best to work in ripe compost on loam and clay soils to loosen up the soil structure. With the help of the organic material, the clay particles combine to form crumbs, between which larger cavities are formed. The air content of the earth increases, rainwater can flow off better and the plants root more easily. Mix in sand if possible. It sustainably improves the water balance by loosening impermeable layers of clay.

In order to remove compaction in the clay soil, the earth should be dug as deep as possible every year before the first severe frost. The minus degrees let the ground water freeze. It expands into small ice crystals and breaks up the compacted clods of earth. This is how what is known as frost proofing is created. If necessary, sow a green manure from spring to late summer, which loosens the ground with its strong roots. For example, oil radish or lupins are suitable for heavy soils.

Subsoil loosening and drainage

Whether more complex measures for soil drainage are necessary depends on the cause of the water stagnation. A compacted soil should be loosened down to the layers that do not allow water to pass. For larger gardens, you should entrust this work to a landscaper, as he has special machines for loosening the soil.

If the subsoil is compacted down to the deeper layers of the earth, usually only a drainage system remains. Several drainage pipes are laid parallel to each other in a bed of gravel or sand in the subsoil. The water seeps through these coarse materials and collects in the perforated tubes. Due to the slight slope of the pipes, the water either flows into nearby trenches or into specially created drainage shafts. Landscape gardeners are usually well versed in laying drainage systems and are familiar with the depth and gradient of the pipes.

Video: take a soil sample and analyze it