Why is fertilization important?
Plants need a variety of nutrients to grow healthy and strong. While in nature they are supplied by the soil, rainwater, and organic decomposition, houseplants depend on our support . The limited amount of substrate in a pot is not enough to provide all essential nutrients over the long term. Without regular fertilization, nutrient deficiencies can quickly develop, manifesting as slowed growth, yellowing or pale leaves, and increased susceptibility to disease .
The most important nutrients for plants
Plants require a balanced mix of major and micronutrients to thrive. The three main nutrients found in most fertilizers are particularly important:
- Nitrogen (N) – Promotes leaf and stem growth. Especially important for foliage plants like Monstera or Philodendron.
- Phosphorus (P) – Essential for strong root formation and promotes flower and fruit formation .
- Potassium (K) – Supports overall plant health, improves disease resistance and regulates water balance.
In addition to these main nutrients, there are a number of micronutrients that are needed in smaller amounts but also play an important role:
- Magnesium – Promotes photosynthesis and ensures lush green leaves.
- Iron – Important for the formation of chlorophyll, prevents iron deficiency (yellow leaves with green veins).
- Zinc, copper, manganese & boron – Support metabolism and various growth processes.
Types of fertilizers: Which fertilizer is right for you?
The choice of the right fertilizer depends on the plant species, the substrate, and individual needs. There are basically different types of fertilizers that differ in their origin and mode of action.
Organic vs. mineral fertilizers
Organic fertilizers
Consisting of natural materials such as compost, horn shavings, guano, or plant extracts, they must first be decomposed by microorganisms in the soil, which allows nutrients to be released more slowly but evenly.
• Environmentally friendly and sustainable
• Promotes soil life and the structure of the substrate
• Low risk of over-fertilization
Mineral fertilizers
Contains synthetically produced nutrients in their pure form. They are immediately available to the plants and act quickly.
• Fast effect, especially in cases of acute nutrient deficiencies
• Precise dosing possible
• Easy to use
Slow-release fertilizer vs. liquid fertilizer
Slow-release fertilizers – These fertilizers release nutrients continuously over several weeks or months . They are ideal for plants that require a consistent supply, such as larger houseplants or potted plants on the patio.
• Less effort, as fertilization is required less frequently
• Even nutrient release
• Reduces the risk of over- or under-supply
Liquid fertilizer – Mixes with water and is quickly absorbed by the roots. It's ideal for tropical plants, herbs, and flowering houseplants .
• Immediate nutrient absorption
• Good dosability
• Ideal for plants in the active growth phase
Dos: The right fertilization for healthy plants
Proper fertilization plays a crucial role in plant growth and vitality. Depending on the plant species and its specific needs, there are different fertilizers specifically tailored to provide essential nutrients. Fertilizing your plants correctly ensures strong roots, lush green leaves, and abundant blooms. However, not only the choice of fertilizer is crucial – the dosage and timing of fertilization must also be considered.
Choose the right fertilizer
Every plant has individual nutrient requirements, so it's important to use the right fertilizer. Leafy plants , like many tropical houseplants, benefit particularly from nitrogen-rich fertilizers , as nitrogen supports the growth of leaves and stems. Plants that are primarily kept for their flowers, such as orchids or flowering houseplants, on the other hand, need phosphorus-rich fertilizers , as phosphorus stimulates flower formation. Cacti and succulents , which receive few nutrients in their natural environment, can get by with very sparing amounts of fertilizer. Too much fertilizer could do more harm than good.
Observe the correct dosage
A common mistake is overdosing on fertilizer in the hope that this will speed up the plant's growth. However, too much of a good thing can burn the roots and cause long-term damage. Therefore, always follow the manufacturer's instructions on the packaging . Particularly sensitive plants should be fertilized with half the dose initially to avoid overfeeding. It is also advisable to adjust the amount of fertilizer according to the season : While regular fertilization is necessary during the growing season in spring and summer , fertilization should be reduced or even avoided during the dormant period in autumn and winter , as most plants slow their growth during this time.
Choose the right time
The timing of fertilization can also determine how well the plant absorbs nutrients. It's ideal to fertilize plants in the morning or evening , when sunlight isn't too strong. This prevents fertilizer residue from evaporating on the leaves and causing damage. Furthermore, fertilization should always be coordinated with the plant's growth phase . Actively growing plants require more nutrients than those in a dormant phase.
Don'ts: Avoid common mistakes when fertilizing
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Applying too much fertilizer at once – Can cause root damage.
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Overfertilization can be just as harmful to plants as a nutrient deficiency. Too much fertilizer can burn the roots and permanently weaken the plant. Therefore, it is important to detect overfertilization early and take targeted countermeasures .
Typical symptoms of overfertilization are brown or yellow leaf tips , which often appear dry and burnt. Curled or wilting leaves can also be a sign that the plant has absorbed too many nutrients. Another clear sign is salt deposits on the soil surface , which are caused by excess minerals and can stress the root system.
If a plant has been overfertilized, there are several ways to limit the damage. One quick measure is to thoroughly rinse the soil with clean water to wash out excess fertilizer salts. In severe cases, it may be necessary to completely replace the soil to provide the plant with a fresh, uncontaminated growth base. Fertilization should also be suspended for several weeks to allow the plant to recover.
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- Applying fertilizer to dry soil – Can burn the roots.
- Using the wrong fertilizer – Not every fertilizer is suitable for every plant.
