The garden soil should not be left open, especially during the winter months, as this contributes to soil erosion. Instead, sow suitable green manure plants that protect the soil and also enrich it with nutrients through their plant mass. However, this effective form of soil improvement must be well planned.

The plants rot on the bed and provide it with nutrients

Table of Contents

Show all
  1. the essentials in brief
  2. What is green manure?
  3. Suitable plants
  4. sowing and timing
  5. Mowing and incorporating
  6. noteworthy
  7. mode of action
  8. benefits
  9. frequently asked Questions
  10. Can you also sow summer flowers and use them as green manure?
  11. Which green manure plants make the soil particularly loose?
  12. Which green manure plants are particularly suitable for the vegetable garden?
  13. Why is winter grain problematic in the vegetable garden?

    14. the essentials in brief

    • With green manure, a so-called catch crop is worked into the soil to improve the soil.
    • Legumes such as beans, peas or lupins are usually grown as cover crops, as they bind nitrogen and release it into the soil.
    • The roots are left around the ground to loosen the soil, the upper parts of the plant are lifted under.

    "The richest soil bears the most weeds." (William Shakespeare, King Henry IV.)

    What is green manure?

    Green manure is a proven method in natural gardening and in organic farming. It is primarily used to cover and improve the soil by incorporating fresh or wilted plants that have been sown for this purpose. The farmer calls these plants "catch crops" because they are not harvested but returned to the natural nutrient cycle.

    It is best to cut green manure plants shortly before or during their flowering so that no seeds form and you end up with a colorful flower meadow instead of a vegetable patch. The roots of the green plants remain in the ground, are gradually decomposed and loosen the soil. The clippings, on the other hand, are left lying around until you sow again, where they serve as mulch material and compost.

    Which plants are suitable for green manure?

    Phacelia not only offers a great green manure, but is also very popular with bees

    Like all plants, green manure plants have their own special requirements in terms of location and soil. Incidentally, legumes, i.e. legumes such as vetches, beans, peas, lupins and also clover, are particularly important for this purpose, as their roots can bind nitrogen from the air and keep it in the soil. This is made possible by so-called nodule bacteria on the roots, the Rhizobium bacteria.

    The following table clearly lists these and other important green manure plants, their site requirements and their effect on soil health.

    kind Latin name sowing location and soil effect on the ground
    broad bean Vicia faba February to July good for dry soil Deep roots for loose soil, good nitrogen collector
    alexandrine clover Trifolium alexandrinum April to October sunny, moist soil Nitrogen collector, suppresses weeds
    bee friend Phacelia April to October very good for nutrient-poor soils Bee pasture, effective against nematodes
    Blue Linen Linum usitatissimum April to June also for partially shaded locations Deep roots for loosening the soil
    Blue lupine, manure lupine Lupinus angustifolius April to October also for partially shaded locations valuable nitrogen collector, deep roots for loose soil
    buckwheat Fagopyrum esculentum May to August for lime-poor sandy and heath soils, also moor soils fruit-neutral (knotweed plant), bee pasture
    Hornbean clover (Common Hornbean clover) Lotus corniculatus March to August very good for lean, dry and calcareous soils Deep roots for loose soil, good nitrogen collector, valuable bee pasture
    oil radish Raphanus sativus var. oleiformis April to September very good for compacted soils Deep roots for loose soil, not before or after cabbage plants
    Pannonian vetch Vicia pannonica August to October for sunny locations good nitrogen collector, for winter cultivation
    red clover Trifolium pratense March to September for deep, fresh soil Deep roots for loose soil, fast-growing, nitrogen-forming
    marigold tagetes May to June very good for partially shaded locations and moist soil Deep roots for loose soil, bee pasture, controls nematodes
    White mustard (also yellow mustard) Sinapis alba March to September very good for compacted soils Deep roots for loose soil, not before or after cabbage plants
    white clover Trifolium repens February to October for sunny locations good nitrogen forming
    winter oilseed rape Brassica napus May to September for nutrient-rich soils good for loosening the soil, for overwintering, not before or after cabbage plants

    digression

    Spinach as green manure

    The hardy spinach (bot. Spinacia oleracea) is also suitable for green manure, but only to a limited extent. The vegetable is suitable as a preculture and should be sown early in the year - between March and May. The strong taproots of the fast-growing plant loosen up the soil and prepare it for suitable subsequent crops. Spinach contains saponins that promote nutrient uptake by other plants, improve soil life and thus indirectly water retention, shade the soil and thus prevent it from drying out. That is why spinach is very suitable for a mixed culture with almost all other vegetables.

    However, the leafy vegetables also have a disadvantage: They accumulate nitrate in the soil and should therefore not be cultivated together with heavy consumers such as peppers, cabbage plants and celery. Other vegetables from the same plant family - beetroot, good Heinrich, Swiss chard, garden cress and rocket - are also not suitable for mixed cultivation and crop rotation.

    If the soil is mulched with spinach, this attracts earthworms - which in turn are essential for the production of valuable, nutrient-rich humus.

    sowing and timing

    Hardy green manure such as mustard can be sown in March

    The green manure is sown between March and October depending on the selected plant species. The best way to do this is as follows:

    1. First remove any growing weeds with a rake.
    2. Thoroughly work the soil with the hoe and loosen the top layers of soil.
    3. Break up the clods of earth with a rake.
    4. Sow the seed broadly in the prepared area.
    5. Alternatively, if available, you can also use a spreader.
    6. Then work the seeds flat into the soil with a wide hay rake.
    7. Finally, go over the seed area with a lawn roller, if available.
    8. Irrigate the area when it is dry.

    Most seeds will germinate in about six to 14 days, depending on the plant species.

    presowing

    Green manure applied in early spring between February and March is called presowing. It primarily serves to nourish and activate the microorganisms living in the soil after the winter. For this form of green manure, choose frost-tolerant plant species such as spinach (bot. Spinacia oleracea), lamb's lettuce (bot. Valerianella locusta), phacelia (bot. Phacelia tanacetifolia) or yellow mustard (bot. Sinapis alba).

    These plants remain in the area until you plant or sow the actual crops. The green manure can remain between the rows of vegetables in the bed as so-called undersown and is only cut occasionally if it grows too much.

    Undersowing and intersowing

    Cover and cover crops are intended to cover the soil between various perennial vegetable crops such as corn, tomatoes, cabbage or berries. Here you apply the green manure plants as soon as the crops have grown. For this purpose, low-growing and annual plants such as nasturtium (bot. Tropaeolum), marigold (bot. Tagetes erecta), marigold (bot. Calendula officinalis) or purslane (bot. Portulaca oleracea) are particularly suitable. A pleasant side effect of these plants is that you can also use them in the kitchen or for the medicine cabinet.

    overseeding

    After the harvest in late summer, the vegetable beds can be covered with overseeding. You can sow these two to three weeks before harvest - for example as undersown between the rows - so that the fallow phase is eliminated. Most of the plants used for this are not hardy and die with the first frost. The effect is intentional, because the soil remains protected and loose under the frozen mass of plants. Instead of frost-sensitive species such as yellow mustard, phacelia or sunflower, you can also plant hardy leafy vegetables such as spinach and lamb's lettuce. However, this variant is only recommended if the beds are to be planted late in the following year.

    When and how do you have to incorporate the green manure?

    Apart from the overwintering species, the green manure plants remain on the beds for about five to ten weeks and are then mowed off. However, do not clear away the plant remains, but leave them on the spot as mulch (€239.00). They rot there and enter the soil as humus. Only low-growing green manure plants such as garden cress and lamb's lettuce are not mowed, but worked directly into the soil from a growth height of approx. five centimetres.

    The green manure is simply incorporated into the soil

    Mow before seed ripening

    Also make sure to mow the plants before the seeds are ripe, otherwise you will have a problem with masses of wildly germinating plants the following year. Green manure plants that are not hardy, on the other hand, usually freeze before the seed ripens and can therefore remain standing. Here you only mow the leftovers in the spring and work them flat into the ground. The bed can be ordered again after another three to four weeks.

    Incorporate green manure plants into the soil

    Mowing is done with a scythe, a brush cutter (€139.99) or a powerful lawnmower. The latter is the device of choice, especially when it comes to a mulching mower. Green manure plants that have been chopped up equally well will rot faster. However, do not work the mowed plants into the soil straight away, but let them dry for a few days first. This is especially true for species with a lot of leaf mass, as they can otherwise rot in the ground. Green manure plants with woody stems (e.g. sunflowers), on the other hand, are not worked in at all, but composted on the compost after they have been well chopped up. Here, the decomposition process is simply too lengthy to work the remains straight into the soil.

    You have to pay attention to this when green manuring

    When choosing plants, there are a few points to consider regarding crop rotation or mixed cultivation. For example, under no circumstances should representatives of the same plant family be cultivated one after the other on the same area, as otherwise certain pathogens would accumulate in the soil and threaten the subsequent harvest. Typical examples are nematodes and clubroot. Furthermore - especially in legumes - excretions of the roots lead to self-incompatibility.

    Observe crop rotation

    For this reason, keep cultivation breaks of three to four years before cultivating a representative of a certain plant family on the area again. In concrete terms, this means: If you want to grow cruciferous vegetables such as cabbage, radishes or radishes in your vegetable patch, you must not sow rapeseed, oilseed radish or mustard as green manure. If, on the other hand, peas and beans are planned, lupins, vetches or clover should not be used for green manure.

    Phacelia for the vegetable garden

    Phacelia, on the other hand, is ideal for the garden, as it is not closely related to any vegetable and therefore mutual interactions are ruled out. The same applies to buckwheat, a knotweed plant that should not be associated with rhubarb. The marigold, also known as marigold, helps against root-damaging nematodes.

    How does green manure work?

    Green manure is not so much actual fertilization as it is a measure to improve the soil. Harvested vegetable beds, but also fruit beds and other garden areas benefit from green manure in several ways. Depending on the choice of plant and the desired benefit, this can be sown as a main crop, catch crop or undersown or, rarely, planted.

    Green manure in the vegetable patch

    Green manure is particularly useful before or after the cultivation of heavy-duty vegetable plants such as tomatoes, peppers, potatoes, artichokes, melons, etc., since these plants leach out the soil despite additional fertilization. Soil-improving measures as well as sensible crop rotation and mixed cultures allow the soil to recover more quickly and harvest yields to increase.

    Green manure for soil improvement

    Unfavorable soil conditions, such as the soil compacted by heavy construction machinery in the new development areas, can be improved with green manure, since the plants loosen the soil with their roots and thus prevent it from silting up. Especially phacelia (bee pasture), winter oilseed rape and yellow lupine are well suited for loosening the soil. At the same time, these plants increase the valuable humus content due to their rotting plant matter.

    Green manure in the orchard

    In the orchard or meadow orchard, flowering green manure plants - sown as undersown - attract many insects, which in turn take over the pollination of the apple and pear trees. This also contributes to a rich fruit harvest, especially since the trees benefit greatly from additional nutrients.

    Green manure has these advantages for the garden

    Apart from the ones already mentioned, green manure has many positive effects on the garden. The dense carpet of plants not only suppresses the growth of unwanted weeds, but also prevents soil erosion and the washing out of nutrients from the fallow soil. This is now no longer unprotected by the targeted planting.

    Enrichment of the soil with nitrogen

    Legumes enrich the soil with nitrogen

    The green manure plants not only receive the nutrients already contained in the soil, but also enrich them with fresh nitrogen. Legumes use the nodule bacteria in their roots to filter the nitrogen out of the air and later, after it has been incorporated into the soil and decomposed, to the following plants. Thus, vetches, beans, peas and lupins act as natural long-term fertilizers.

    Loosening of compacted soils

    Green manure plants with deep roots - such as alfalfa and oilseed radish - are also able to loosen up heavily compacted soil and thus make it usable in the first place. This property is particularly important in new development areas, where the soil is often very compacted due to the construction activity with heavy machinery.

    Enrichment with humus material

    Still other species - for example winter vetch or phacelia - are perfect for enriching depleted and/or sandy soils with humus and making them fertile again. These plant species develop a lot of leaf and flower matter, which composts in the soil and thus activates the soil organisms quite incidentally.

    Advantages of green manure at a glance:

    • Rapid greening of fallow areas
    • Protection of the soil from weather influences and thus from erosion
    • deep loosening and aeration of the soil
    • improvement of the soil structure
    • Enrichment of the garden soil with nutrients
    • Activation of the soil organisms important for the formation of humus
    • Uptake of nutrients (especially nitrogen) from the air
    • Utilization of nutrients from deeper soil layers
    • Suppression of weed growth
    • Clippings produce valuable mulch material
    • Insect pasture using flowering green manure plants
    • some cover crops control nematodes (roundworms) and fungal diseases in the soil

    The following video shows very clearly how the soil can be improved with green manure and what you have to pay attention to in concrete terms:

    frequently asked Questions

    Can you also sow summer flowers and use them as green manure?

    Of course, you can also use summer flowers for green manure, especially since you are not only doing something good for your garden: the flowering plants attract numerous insects and serve as valuable pasture for bees, bumblebees, butterflies and other animals. This nutritional function is all the more important the later it is in the year, since many insects can no longer find enough food from the summer months. Borage, vetches, marigolds, marigolds and sunflowers are particularly suitable for this purpose.

    However, flowering green manure also has a disadvantage: as soon as the seeds ripen, you will always have colorful flowers in the garden in the years that follow - usually exactly where you don't want them. For this reason, you must mow the plants in good time before the seeds ripen. Also note the crop rotation, which is particularly important in the vegetable garden: never plant plants from the same plant family in the same place one after the other. This promotes diseases! For example, marigolds and sunflowers may not be grown before or after lettuce.

    Which green manure plants make the soil particularly loose?

    The cultivation of cover crops has different effects on the garden soil, depending on the type of plant selected. Solid and compacted soils, which are unfortunately typical in new development areas due to the construction machinery, cannot be loosened with mechanical work alone. To loosen the soil, also plant deep-rooted plants such as bitter lupins (or lupins in general), oilseed radish or sunflowers - their roots also reach the lower layers of the soil and thus ensure better aeration and permeability.

    Which green manure plants are particularly suitable for the vegetable garden?

    Choosing the right green manure for the vegetable garden is not that easy, after all, for reasons of plant health, plants of the same family must not be grown one after the other. However, this means that many of the green manure plants that are otherwise recommended are omitted, because cruciferous plants such as mustard, cress or rapeseed do not get along with cabbage plants and radishes - clubroot would be the unpleasant result. However, there are also well-suited green manure plants that are true all-rounders and can actually always be cultivated: Phacelia is one of them, but also winter cereals such as winter barley or winter rye.

    Why is winter grain problematic in the vegetable garden?

    Winter cereals as green manure plants have many advantages: the seeds are cheap and as cereals the various types are not related to any vegetables and can therefore be sown without hesitation. However, winter rye and co. have one disadvantage: they develop a very dense root system, which can only be removed or incorporated in the spring with a lot of strength and effort.

    tips

    If you want to use legumes such as clover or lupine for green manure, fertilize the soil with some primary rock flour or algae lime before sowing. The natural material promotes the activity of the nodule bacteria in the roots of the plants.

Category:

Vegetable garden