Hobby gardeners often notice from the deficiency symptoms in their plants that the soil is not optimally supplied with nutrients. They apply fertilizers, often unaware that they are doing more harm than good with ill-considered fertilizing.

Compost is a great all-around fertilizer

Table of Contents

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  1. the essentials in brief
  2. Needed Nutrients
  3. Fertilize efficiently
  4. Ideal time
  5. Fertilize organically
  6. Unsuitable fertilizers
  7. frequently asked Questions

    8. the essentials in brief

    • Plants need, among other things, phosphorus (P), nitrogen (N), potassium (K), magnesium (Mg), calcium (Ca) and iron (Fe)
    • The correct fertilization depends on the nutrient requirements of the plants and the pH of the soil
    • In the spring, beds should be fertilized with three liters of compost per square meter
    • Compost, horse manure, and coffee grounds are good organic fertilizers

    What nutrients do plants need?

    Plants need nutrients and trace elements for healthy growth. These are naturally present in the soil, although the composition can vary depending on the type of soil. The vitality of a plant is influenced by the nutrient that is at a minimum. If the concentration of a substance is too low, deficiency symptoms occur.

    symbol importance
    phosphorus P serves for flower, seed and fruit development
    nitrogen N promotes formation of chlorophyll
    potassium K ensures water transport and plant stability
    magnesium mg supports metabolic and photosynthetic processes
    calcium Approx important building block of cell walls
    iron feet promotes plant growth and fruit yield

    Fertilize efficiently

    The right fertilization is a science in itself, because numerous factors influence the frequency and intensity of the nutrient supply. Heavy feeders need more nutrients than weak feeders. A fertilizer recommendation is only possible if the soil has been analyzed beforehand.

    How to fertilize properly:

    • apply three liters of compost per square meter every spring
    • Fertilize heavy feeders with horn shavings (32.93€) in late spring
    • Supply plants in acidic locations with horn shavings once a year

    soil pH

    Lime is used in acidic soils

    How well the nutrients can be absorbed by the plants depends on the pH of the soil. This describes the acidity and can be in the acidic, neutral or basic range. The majority of all cultivated garden soils are slightly acidic, with a pH of 6.0. Most plants prefer this value.

    The pH value can be increased by adding lime. The substrate becomes loose and microorganisms make nutrients available to plants. Liming every three to four years is enough. Otherwise there is a risk that the soil will be leached. If the substrate is too alkaline, it can be mixed with bog soil.

    soil type

    Basically, a distinction is made between light, medium-heavy and heavy soils. The soils in Central Germany are mostly heavy because they contain clay. Heavy substrates can store nutrients better than sandy soils, which predominate in northern Germany. They therefore need to be fertilized less often, while sandy soils require more frequent nutrient supply. These can be improved with green manure or compost.

    Fertilization tailored to the soil:

    • heavy soils: add nitrogen
    • medium-heavy soils: fertilize in case of deficiency symptoms
    • light soils: improve with compost, green manure or mineral fertilizer

    When is the best time to fertilize?

    When you need to fertilize your plants depends on the environmental conditions. As soon as the growing season begins and the plants sprout, nutrients are needed. It is ideal if you have already fertilized before sprouting. Subsequent fertilizer applications are not a problem as long as you follow a few rules:

    • fertilize in the morning so that the plant can absorb nutrients with the water during the day
    • do not fertilize when it rains, as the nutrients will be washed away
    • moisten the substrate before the mineral nutrient supply so that nutrients can dissolve

    Hungry plants like tomatoes need fertilizer several times

    Fertilize throughout the year

    Long-term fertilizers such as horn shavings can be worked into the bed as early as late autumn. They decompose slowly so that the plants are supplied with nutrients in spring in time for budding. Depot fertilizer or granules are placed directly in the planting hole so that perennials and shrubs can draw nutrients directly.

    Compost as a universal fertilizer is worked into the substrate in spring. This will ensure your plants get the best start to the growing season. If you use readily available artificial fertilizers, you should use them when needed.

    • only fertilize in the growth phase between March and August
    • Only use nitrogenous mineral fertilizers between the end of March and July
    • Apply potassium-rich fertilizers in late summer

    Fertilize organically

    Organic fertilizers are an ecological alternative to artificial fertilizers. Farming produces by-products that are used as natural nitrogen fertilizers. These slowly release the nutrient as they decompose in the soil over time. Over-fertilization is thus prevented. Compost is an ideal complete organic fertilizer that activates soil life.

    Fertilizers with main nutrients:

    • nitrogen: Horn shavings, feather or bone meal
    • iron: plant manure
    • potassium: Sheep's wool pellets
    • phosphorus: Rock flour, (14.13€) cattle and horse manure
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    horse manure

    Horse manure contains a variety of important nutrients and also improves soil vitality. This organic fertilizer is ideal for heavy consumers and can also be used to provide nutrients for lawns, hedges and fruit trees or flower beds. Do not use fresh manure as this may contain seeds of various weeds. In addition, the ammonia content in fresh manure is very high, which negatively affects the soil quality. A year's stored manure, in which the seeds have been killed by sunlight or hot rotting, can safely be used for fertilization.

    How to use horse manure correctly:

    • suitable for tomatoes, pumpkin, zucchini and corn
    • about two to four liters of horse manure per square meter
    • Work in a maximum of 30 centimeters deep
    • alternatively mix in the compost

    compost

    Countless microorganisms ensure that plant materials are decomposed. In order for the processes to run optimally, both air and moisture are necessary. Optimal compost produces high temperatures, which kills weed seeds. Fresh compost is a universal fertilizer suitable for almost all plants. However, the nutrients vary greatly depending on the composted plant material. The nitrogen content is usually between one and two percent.

    digression

    C/N ratio in compost

    Microorganisms need nitrogen to form new cells. The ratio of carbon to nitrogen is crucial for the reproduction of microorganisms. Ammonia is formed when there is an excess of nitrogen. This shifts the pH value into an unfavorable range, which means that further decomposition processes suffer. Sawdust helps in this case because it has a high carbon content and a low nitrogen content.

    coffee grounds

    Coffee is often used as a fertilizer, but should be dosed well

    Raw coffee beans have a protein content of eleven percent, which is completely broken down by roasting. Roasting produces humic acids, giving coffee grounds a slightly acidic pH compared to fresh coffee beans. Unroasted beans contain nitrogen, sulfur and phosphorus. These nutrients are largely retained in the breakdown products, which is why coffee grounds are ideal as fertilizer.

    Fertilize properly with coffee grounds:

    • good for hydrangeas, rhododendrons and blueberries
    • Work the coffee grounds into the bed and then mulch
    • When repotting, mix a handful of coffee grounds into the fresh potting soil

    tips

    Houseplants should be fertilized weekly with half a cup of diluted black coffee. Coffee grounds on the root ball tend to mold quickly.

    Unsuitable fertilizers

    Artificially produced fertilizers are highly concentrated and give the plant nutrients that do not have to be converted beforehand. They are immediately available to plants. There are artificial fertilizers in liquid or solid form. So that the nutrients are released more slowly, synthetic fertilizer beads are surrounded by a protective cover. The production of such products is very energy-intensive. In the wrong dosage, plant growth suffers, so damage is inevitable. In addition, chemical fertilizers adversely affect the environment when they are washed into water bodies.

    Why spend a lot of money on artificial fertilizers? These products hardly offer any advantages.

    ash

    While wood ash can be used for liming, it should not be used as a regular fertilizer. The pH of pure ash can range from 11.0 to 13.0. Calcium is in its most aggressive form, burnt lime. This can lead to leaf burns and affect soil life, especially in light sandy soils. In agriculture, only unvegetated and heavily loamy or clayey soils are limed with calcium oxide.

    tips

    If you put ash on the compost, you should only light the wood with sticks, leaves and pieces of bark. Recycled paper may contain mineral oil residue.

    frequently asked Questions

    What is horn shavings, horn semolina and horn meal?

    Horn shavings are made from ground up cattle hooves, claws and horns. Horn semolina is coarsely ground horn shavings with a grain size of between two and five millimeters. If the degree of grinding is less than two millimetres, the product is referred to as horn meal. The finer the particle size, the faster the fertilizer decomposes and becomes available to plants. Decomposition is carried out by microorganisms. These fertilizers serve to supply nitrogen and improve the formation of humus in the soil. They can be added to the compost to increase the nitrogen content.

    Why is blue grain unsuitable as fertilizer?

    This fertilizer was very popular in the garden for a long time because, as a complete mineral fertilizer, blue grain contains nitrogen, phosphate and potash in a water-soluble form. However, nitrogen is present as water-soluble nitrate, most of which is washed out by rain and can get into the groundwater. These so-called NPK fertilizers do not provide any food for soil organisms and impair the formation of humus. The result of years of use of blue grain is an oversupply of phosphate and potash.

    How often should I fertilize?

    Statistics from the soil laboratories show every year that the soils in private gardens are sometimes heavily over-fertilized. The phosphate content is often extremely high and the potassium content is also too high. According to estimates, 90 percent of all hobby gardeners fertilize by feel without first analyzing the soil. The use of complete mineral fertilizers or special fertilizers accumulates phosphate and potassium in excessive amounts. It is therefore better to fertilize too little than too much.

    Which fertilizer should I choose?

    Compost is considered an all-purpose fertilizer that is suitable for almost all plants, especially heavy feeders. Compost is not recommended for plants that prefer acidic soil. These should be better supplied with coffee grounds. Fertilizing with cottonseed meal ensures that the pH value remains in the acidic range.

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Garden design