If clay soil comes under the wheels of construction machinery and heavy equipment, the quality suitable for plants is lost. This guide explains how to skilfully improve compacted clay soil and turn it into exemplary garden soil. Practical tips convey how drainage in the garden clay soil optimizes rainwater infiltration. You can find out here which plants thrive in clay soil.

Clay soil must be worked up so that it can be farmed well

Table of Contents

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  1. the essentials in brief
  2. improve clay soil
  3. drainage garden clay soil
  4. Plants for clay soil
  5. Dispose of clay soil
  6. frequently asked Questions

    7. the essentials in brief

    • Mature compost and fine-grained quartz sand (15.85€) is a tried and tested means of improving compacted, wet clay soil.
    • Drainage in the garden loamy soil with a drainage trough guarantees permanent protection against waterlogging.
    • Roses, hydrangeas, apple trees and many other plants like clay soil if the rainwater infiltration is working.

    Improving clay soil - this is how it works

    Clay soil has a very fine-grained structure that tends to be massively compacted. A high proportion of clay exacerbates the problem. The soil becomes so hard and sticky that plant roots are stunted in their growth. Rainwater cannot run off, or only very slowly. The fatal consequence is waterlogging in the upper soil layers, recognizable by puddles in the lawn and bed. As a result of water saturation, valuable lime is washed out, causing the pH value to drop and the garden soil to become acidic. It doesn't have to come to that if you loosen up clay soil and make it more permeable. How to improve clay soil with gardening expertise:

    1. Dig the soil spade-deep, rake vigorously, remove weeds, stones and debris
    2. Work mature compost into the clay soil (3-5 l/m² at least)
    3. level improved clay soil with a rake
    4. Spread sand in a layer height of 2-5 cm and rake in
    5. Measure the pH value with a test set from the hardware store
    6. Lime the garden soil if the result is below a pH value of 5.5

    From now on you dig the clay soil one or two spades deep every year before the first frost. Sub-freezing temperatures freeze the water in the ground. Small ice crystals form, which burst open the compacted earth and in this way loosen it even more. In addition to frost sowing to loosen the soil, sow green manure with deep-rooted plants such as lupins (Lupinus), red clover (Trifolium) or marigolds (Calendula) in spring.

    Special case clay soil under lawn

    A scarifier can be used to loosen up clay soil under the lawn

    Compacted clay soil makes life difficult for the noble grasses in the lawn. The delicate roots can hardly penetrate a compact topsoil and drown in waterlogging after every downpour. To avoid having to dig up the lawn to improve the clay soil, rent or buy a manual or powered lawn aerator, also known as an aerator or aerator. How to proceed correctly step by step:

    1. Mow lawn, scarify and sweep
    2. Aerate area with 200 holes per square meter
    3. Sand and sprinkle the aerated lawn
    4. Repeat measure every year in March/April and September/October

    The above procedures are helpful when there is no drainage in clay soil. You can use this method to drain waterlogged garden soil, at least for a while. Are you interested in permanent rainwater infiltration? Then the work and costs for a pipe system with an infiltration pit are worthwhile. You can read tips for uncomplicated DIY drainage in the garden clay soil in the next section.

    Creating drainage in the garden clay soil - tips

    If the soil is very solid, drainage in the garden makes sense

    Lawn will not grow on clay soil if the rainwater stops. Annual scarifying and aerating only solves the problem temporarily. If flowers, perennials and vegetable plants stand there with wet feet after every heavy downpour, growth depression and crop failures are inevitable. Affected gardeners tackle the problem at the root with permanently improved rainwater infiltration. The following tips outline a simple variant of how you can use drainage to make clay soil with waterlogging more permeable over the long term:

    preparatory work

    Measure the course of the pipe system for the drainage to the infiltration system exactly. You then create a detailed plan sketch so that you can precisely determine the material requirements. Write down slotted drainage pipes that are coated with coconut fiber on the shopping list. The special drainage pipes end in a collecting line that allows the water to flow into a drainage basin. In addition, you need sand, gravel, grit, (46.95 €) seepage fleece, wooden slats as formwork, spade, shovel, ideally a mini excavator or strong helpers for the sweaty excavation work.

    Lay drainage pipes and collection line

    A slight incline of 2 to 3 percent is of crucial importance for the functioning of drainage in garden loamy soil. Regular checks with the spirit level guarantee compliance with this important premise when excavating the clay soil and then filling the ducts. The following guidelines are also relevant to ensure that rainwater infiltration in the garden becomes a successful project:

    • Dig channels for the drainage pipes (15-30 cm under the lawn/turf, 80-150 cm under the vegetable patch and orchard)
    • Use wooden boards as formwork in the pits
    • Line pipe ducts with seepage fleece
    • Fill in a layer of sand to protect the fleece and then fill in the gravel packing
    • Lay drainage pipes and collection line

    It is important to note that there is sufficient distance between the drainage pipes and the basement of your home so that you don't have to struggle with wet basement walls. It must be ensured that rainwater from the drainage pipe does not get into the house's seepage shaft and flow into the sewer. Under these circumstances, trouble with the authorities is inevitable and the sewage fees skyrocket.

    septic tank

    A drainage trough is the simpler variant of drainage

    A drainage trough solves two problems in one operation. If the size of the garden area allows it, the trough acts as a collection basin for the collection line of the drainage pipes and blends harmoniously into the creative garden design as a natural wet biotope. Important key points are summarized in the following overview:

    • Dig a drainage trough below the collection line for the drainage pipes
    • ideally digging at the site down to a permeable layer of soil (no gravel packing or filter fleece required)
    • alternatively, line dense clay soil with fleece and fill with sand and seepage gravel

    In contrast to the soakaway in the house, a simple drainage in the garden clay soil does not require a building permit. This requirement applies as long as the construction is limited to optimizing the natural infiltration of rainwater into the lawn or garden soil. Measures to drain clay soil that go beyond this are subject to legal regulations, such as the Water Resources Act or the building code. In many municipalities, it is also forbidden to drain rainwater into the public sewage system using garden drainage. Therefore, please contact the responsible authority if your plans go beyond the simple drainage variant explained here.

    tips

    A visible part of a garden drainage is the seepage trough as a wet biotope. The pipelines resting in the ground were quickly forgotten. Photograph the course of the pipe system and keep the photos together with the plan sketch so that there are no nasty surprises later when working on the soil in the bed.

    Ideal plants for clay soil - premium selection

    Flame flower grows well in clay soil

    Which plants actually like clay soil? Which trees grow on clay soil? To save you a long headache, we have compiled the following table. These plants like to stretch out their roots in rich, heavy clay soil:

    Perennials/Vegetables/Herbs botanical name shrubs/ground cover botanical name trees/fruit trees botanical name
    Aster, Toughleaf Aster Aster novae angliae roses pink sweetgum Liquidambar styraciflua
    flame flower Phlox paniculata hydrangeas Hydrangea trumpet tree Catalpa bignonioides
    sun bride Helenium Black Currants Ribes nigrum Redwoodtree Metasequoia glyptostroboides
    Bergenia Bergenia white willow Salix alba sycamore maple Acer pseudoplatanus
    splendor pier astilbe White Dogwood Cornus alba Spruce Picea
    peony Paeonia officinalis purple willow Salix purpurea cedar cedrus
    tomatoes Solanum lycopersicum shadow green Pachysandra terminalis apple tree Malus domestica
    potatoes Solanum tuberosum Medlar Cotoneaster procumbens plum tree Prunus domestica
    onions Allium cepa button bush Cephalanthus occidentalis cornel Cornus mas
    carrots, carrots Daucus carota subsp. sativus Red winter berry Ilex verticillata quince Cydonia
    All kinds of cabbage Brassica hornbeam Carpinus betulus Sloe (large shrub) Prunus spinosa
    chives Allium schoenoprasum Clematis clematis Black elder (large shrub) Sambucus nigra
    peppermint Mentha piperita yew Taxus baccata
    thyme Thymus vulgaris tree of life Thuja

    The best lawn seeds for clay soil should consist primarily of deep-rooted grasses, such as meadowgrass (Pos supina). When selecting the type of lawn, a distinction must also be made as to whether it is a location in the sun or in the shade. A look at the back of the packaging gives more information.

    digression

    Buy clay soil

    Building on clay soil leaves a massively compacted topsoil. Instead of dedicating yourself to extensive soil improvement and drainage measures, you can remove the dense, waterlogged layer of soil and buy fresh, top-quality clay soil. Buying sources for loam in top form are local building material suppliers, container services and composting sites. Depending on the season, civil engineering companies and gardening companies have high-quality loamy soil on offer as topsoil at low prices.

    Dispose of clay soil properly

    If clay soil is no longer of any use after it has been removed, you have a number of options. How to dispose of clay soil in an exemplary manner:

    • Sieve clay soil, transport it with a trailer and hand it in to the gardening company or the municipality free of charge
    • Rent a truck and driver, shovel clay soil onto the loading area and let it drive away
    • Publish sifted clay soil (without rubble) in Bodenbörse for pickup
    • Assign disposal to a specialist container company

    It is important to note that, despite all the complaints, clay soil that has been removed is still a living natural asset that must not be carelessly destroyed.

    frequently asked Questions

    How to prepare clay soil for lawn?

    Lawn grasses want their subsoil to have a loose, permeable consistency. Lay out a rough subgrade and a fine subgrade in two steps so that compacted, waterlogged loamy soil enjoys the goodwill of noble grasses. In the first phase you dig up the clay soil, removing roots, weeds and stones. Then work in the lawn sand at 4 kg/m² and leave the rough subgrade to rest for two weeks. For the fine planum, rake, weed and rake the improved clay soil until it has a fine, crumbly consistency.

    Which sand is best for improving clay soil?

    Fine-grain quartz sand is a good choice for allowing rainwater to seep away more quickly in dense clay soil. However, the first choice is associated with comparatively high costs with an average price starting at 0.24 euros/kg. Soil improvement is cheaper with fine-grained, washed building sand, which costs 0.12 euros/kg.

    In our garden, sandy loamy soil allows rainwater to seep away far too quickly. What to do?

    Mature compost and bark humus improve the water storage capacity in sandy loam. The higher the proportion of sand, the more organic soil additives you should incorporate. Green manure every spring is beneficial for soil quality. Plants such as lupins, bee-friends, marigolds or red clover enrich sandy loamy soil with green matter and root mass, so that soil water does not seep away as quickly.

    tips

    If clay soil had a say in the garden, lava granules would be at the top of the wish list for soil improvement. Cooled lava with a grain size of 4-16 mm or 16-32 mm effectively prevents unfavorable compaction and the resulting waterlogging. Because lava granulate (€13.99) does not rot, loamy garden soil benefits from reliable rainwater infiltration for many years.

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