In brief: For successful garden fertilisation, choose the right fertiliser for your plant type and soil condition. Apply it during the growing season, from spring to late summer. Organic fertilisers work slowly and improve the soil, while mineral fertilisers provide quick results. Always follow the dosage instructions to avoid over-fertilising.
A lush garden with strong plants and a plentiful harvest is every gardener's dream. The key lies in the soil. Over time, plants remove important nutrients from the soil that are essential for their growth. Targeted garden fertilisation replaces what the soil needs and ensures your plants receive an optimal supply of nutrients. But which fertiliser is right, and how should you apply it correctly? This guide covers everything you need to know.
Why is fertilising the garden necessary at all?
Think of garden soil as a nutrient bank account. Every plant that grows, flowers and produces fruit withdraws nutrients from this account. Rain also washes nutrients out of the upper soil layers. Without regular deposits, the account eventually runs empty. The result: plants grow poorly, become more susceptible to diseases and pests, and yields remain low.
The three most important nutrients, known as macronutrients, are nitrogen (N), phosphorus (P) and potassium (K).
- Nitrogen (N) drives growth. It is essential for producing green leaves and strong shoots.
- Phosphorus (P) promotes flower formation, fruit ripening and strong root growth.
- Potassium (K) strengthens plant cell walls, improves stability and increases resistance to frost, drought and disease.
In addition to these primary nutrients, plants also need trace elements such as magnesium, calcium and iron. Good garden fertilisation replaces the nutrients removed from the soil and ensures that all elements are available in sufficient quantities.
Soil is a living organism. Those who care for and feed it not only harvest abundant fruit, but also contribute to biodiversity.
What types of fertiliser are available? An overview
You will find a wide range of different fertilisers in shops. In general, they differ in their origin and how they work. The right choice depends on your plants, your soil and your personal preferences.
Organic fertiliser: The power of nature
Organic fertilisers are made from plant or animal materials. They include compost, farmyard manure, horn shavings, bone meal and plant teas. Their greatest strength is that they not only feed plants, but also improve soil structure over the long term. Soil microorganisms slowly break down the organic material and release the nutrients gradually. This prevents rapid leaching and reduces the risk of over-fertilising.
A living soil filled with earthworms and microbes is the result when you regularly use organic fertiliser. The soil becomes looser, stores water more effectively and becomes more fertile. A good example is the
organic lawn fertiliser, which not only feeds the lawn but also promotes soil activity.
Mineral fertiliser: A fast supply of nutrients
Mineral fertilisers, also often called synthetic fertilisers, contain nutrients in the form of industrially produced salts. They are highly concentrated, and the nutrients are immediately available to plants. This makes them ideal as a quick fix for acute nutrient deficiencies, which can show up as yellow leaves or weak growth.
However, you must dose mineral fertilisers precisely according to the instructions. Overdosing can damage the plant roots (“burn” them) and harm soil life. In the long term, they do not improve soil structure.
Organic-mineral fertiliser: The best of both worlds
These fertilisers combine the benefits of both types. They contain readily available mineral components for an immediate effect as well as organic ingredients for a long-lasting supply of nutrients and improved soil. They are a good compromise for many gardening applications.
Expert tip
For truly targeted fertilisation, a soil test is worthwhile. Laboratories or test kits from specialist retailers provide precise information about which nutrients are lacking in your garden soil. This allows you to fertilise precisely and avoid wasting money or burdening the soil with excess nutrients.
How do I choose the right fertiliser for my plants?
Not every plant has the same appetite. Gardeners divide plants into three groups according to their nutrient requirements: heavy feeders, medium feeders and light feeders. This classification helps you choose the right amount and type of fertiliser.
Heavy feeders: The hungry plants in your beds
These plants need plenty of nutrients to produce large fruit and a rich harvest. They benefit from thorough basic fertilisation with compost in spring and regular additional feeding throughout the season. Special plant and flower fertilisers are ideal for this.
- Examples: Tomatoes, cucumbers, courgettes, pumpkins, potatoes, cabbages, sunflowers and dahlias.
Medium feeders: The undemanding plants
Medium feeders have moderate nutrient requirements. They often need just a single application of compost in spring or occasional feeding with a balanced garden fertiliser.
- Examples: Carrots, onions, lettuce, spinach, strawberries and most perennials.
Light feeders: The modest plants
These plants manage with very few nutrients. They grow best in soil that was used for heavy or medium feeders the previous year. Too much fertiliser can even harm them, resulting in excessive growth and less flavour in herbs.
- Examples: Beans, peas, radishes, lamb's lettuce and most herbs such as thyme or rosemary.
For vegetable plants and herbs, a liquid organic fertiliser such as the
vegetable fertiliser is ideal. Simply mix it with the irrigation water to provide your plants with the nutrients they need.
Additional advice
A mulch layer made from grass clippings, leaves or straw protects the soil from drying out and suppresses weeds. As the materials decompose, they slowly release nutrients into the soil and support soil life. Mulching is an excellent addition to targeted fertilisation.
When and how often should I fertilise my garden?
Choosing the right time is crucial for successful fertilisation. The main fertilising season is the growing season, which begins in spring and ends in late summer. In autumn and winter, most plants are dormant and do not need any additional nutrients.
Spring (March/April): This is the time for basic feeding. Work mature compost or an organic slow-release fertiliser into the beds. This gives the plants a good start to the season.
Summer (May to August): During the main growing and flowering period, heavy feeders in particular have high nutrient requirements. This is the right time for additional feeding. You can apply liquid fertiliser every two to four weeks. Depending on how long they work, solid fertilisers should be reapplied once or twice.
Late summer (end of August): Reduce fertilisation, especially with nitrogen-rich fertilisers. The plants should stop growing and prepare for winter. New, soft shoots would be damaged by frost.
Step-by-step guide: How to apply fertiliser correctly
Applying fertiliser correctly ensures that the nutrients reach the roots without damaging the plant.
Applying solid fertilisers (granules, pellets, horn shavings)
- Read the instructions: Always follow the quantities specified on the packaging. Less is often more.
- Measure it out: Use a measuring cup or scales to determine the exact amount for the size of your bed.
- Spread evenly: Scatter the fertiliser evenly around the plants. Avoid spreading the granules directly around the plant stem or on the leaves.
- Work it in: Lightly work the fertiliser into the top layer of soil using a rake or cultivator. You can find the right garden tools in our range.
- Water: Water the area thoroughly afterwards. The water dissolves the nutrients and carries them to the roots.
Using liquid fertiliser
Liquid fertilisers such as the vegetable fertiliser are particularly easy to use.
- Mix: Add the amount of fertiliser specified in the instructions to a watering can filled with water.
- Apply: Pour the nutrient solution directly onto the plants' root area. Never fertilise dry soil, as this can damage the roots. If necessary, water the plants with clean water beforehand.
- Frequency: Repeat the application every few weeks during the main growing season, depending on the plants' needs.
Good garden irrigation is the foundation for plants to absorb nutrients effectively.
Important note
Avoid over-fertilising. Too many nutrients, especially nitrogen, lead to unnaturally fast, excessive growth. The plants become soft, unstable and susceptible to pests such as aphids. Excess fertiliser can also leach into groundwater and harm the environment.
Working in compost and manure
Mature compost is a gardener's gold. It not only supplies nutrients but also improves the soil structure. To make it, you can shred garden waste using the
\"Wunderschere\", which is ideal for this purpose, and add it to a compost heap.
In spring, spread a 2-3 cm thick layer over the beds and work it lightly into the soil. Farmyard manure should be well rotted before use, as fresh manure is too strong for plant roots. The best time to apply it is in autumn, allowing it to break down over winter.
Fertiliser is not there to feed the plant, but to invigorate the soil.
By fertilising your garden consciously and correctly, you create the foundation for healthy growth, strong plants and a rich harvest. You complete the nutrient cycle and maintain sustainably fertile soil that will bring you joy year after year.
Frequently Asked Questions
- When is the best time to fertilize the garden?
- The best time to fertilize is during the growing season, from spring to late summer. Apply a base dressing of compost or slow-release fertilizer in spring. You can apply liquid fertilizer every few weeks during the main growing period. Stop fertilizing after late summer so that the plants can become hardy for winter.
- What does NPK mean on fertilizer packaging?
- NPK stands for the three main nutrients plants need: nitrogen (N) for leaf growth, phosphorus (P) for flower and root development, and potassium (K) for fruit ripening and resilience. The ratio of the numbers indicates the percentage of each nutrient.
- Can you fertilize too much?
- Yes, overfertilizing can harm plants and the environment. Too much nitrogen leads to soft, disease-prone shoots. Excessive fertilization can burn the roots and increase the salt content of the soil. Always follow the manufacturer's dosage recommendations precisely.
- Is coffee grounds a good fertilizer?
- Yes, coffee grounds are a good, mild organic fertilizer. They contain nitrogen, phosphorus, and potassium. Dry the coffee grounds thoroughly and work them into the top layer of soil. They are especially suitable for plants that prefer slightly acidic soil, such as hydrangeas, rhododendrons, and blueberries.
- How can I recognize nutrient deficiencies in plants?
- Nutrient deficiencies often appear as discolored or stunted leaves. Pale or yellow leaves (chlorosis) often indicate a nitrogen or iron deficiency. Poor growth, few flowers, or purple discoloration of the leaves can point to a phosphorus deficiency. A professional soil test provides the most reliable information.
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