Organic vs. Mineral Fertilisers: What's Better for Your Plants?

Every beginning grower faces the choice of how to fertilise their plants. While organic fertilisers are gentle on the environment and require less work, mineral fertilisers act quickly and give the grower complete control over plant nutrition. We will guide you through the basic differences between organic and synthetic fertilisers and help you choose.

While organic fertilisers are made from materials of organic origin, such as compost, manure, bone meal and the like, synthetic ones are obtained through human-controlled chemical reactions, for example from ammonia, phosphate minerals or air. Synthetic fertilisers contain an exact amount and ratio of nutrients in a form that is quickly available to plants, mainly as mineral salts. On the other hand, organic fertilisers contain nutrients that must first be broken down in the soil by microbes, and only then can plants absorb them through their roots. This process is slower, but it has the advantage of keeping the soil healthy in the long term. The use of mineral fertilisers leads to the death of important microorganisms, and in the long term the soil loses its ability to regenerate. Before we move on to choosing the right fertiliser for your garden, let us summarise the basic advantages and disadvantages of organic and synthetic fertilisers.

Organic fertilisers PROS and CONS

• Gentle on the environment: Organic fertilisers improve soil structure, support beneficial microbes and pollute water sources less.
• Sustainability: They come from renewable sources and are in line with ecological growing practices.
• They strengthen soil health: Long-term use of organic fertilisers enriches the soil, which becomes more fertile and more resistant to external influences.
• Slow action: When organic fertilisers are applied, nutrients are not available to plants immediately.
• Volume and storage: Organic fertilisers are used in larger quantities and may be bulkier than synthetic ones.
• Odour: Some organic products, such as livestock manure, guano or fish meal, can smell strongly and unpleasantly.

Synthetic fertilisers PROS and CONS

• Fast action: Synthetic fertilisers act immediately, which is ideal for addressing nutrient deficiencies or intensive growing methods.
• Precise fertilisation: Mineral fertilisers are easy to dose, and you can easily adapt nutrition to the specific requirements of plants.
• Use in hydroponics: Mineral salts are suitable for preparing nutrient solutions and ideal for hydroponic and soilless growing.
• Risks to the environment: Careless and excessive use of mineral fertilisers degrades the soil, and salt residues can leach into the surroundings.
• Soil degradation: Repeated application can disrupt the soil microflora and thus reduce soil health in the long term.
• Non-ecological production: The extraction of raw materials and the production of synthetic fertilisers have a harmful impact on the environment.

Organic fertilisers: The ideal helper for outdoor growing

Organic fertilisers are best used for outdoor growing, for example in beds, but also in greenhouses. Some types of organic fertilisers, especially liquid formulations, can also be used when growing in pots, but keep in mind that they act more slowly than mineral salts. For the best effect of these fertilisers, the soil should contain a high proportion of organic matter and microorganisms that speed up the breakdown of nutrients. The most commonly used organic fertilisers include compost, guano and vermicompost. You can also use compost teas and liquid fertilisers of organic origin, such as Biobizz. When choosing and applying fertilisers, always take into account the type of plants you want to grow and the season. Add compost or manure to the bed in autumn so that the organic matter has enough time to break down. If you encounter nutrient deficiencies during the growing cycle, you can quickly solve the problem by applying mineral fertilisers, but remember that in the long term you must enrich the soil with organic matter.

Synthetic fertilisers: Precise plant nutrition

Synthetic fertilisers are an excellent tool for indoor growing and everywhere plants cannot be grown in a natural way. They are ideal for growing in pots, but with careful use they can also be applied to open ground. You can use them in combination with soil mixes or various types of soilless substrates, such as coco, perlite or expanded clay. Mineral fertilisers are also used to prepare nutrient solution for hydroponics. Remember that, unlike organic fertilisers, they deplete nutrients from the soil or substrate very quickly, and you will need to fertilise with every watering. When using synthetic fertilisers, it is important to monitor the pH of the substrate and, if necessary, also the EC of the nutrient solution using a digital EC and pH meter. Choose mineral fertilisers according to the current requirements of the plants. In general, plants need more nitrogen for growth, while during flowering and ripening they use more potassium. Most manufacturers of mineral fertilisers label their products as “grow” and “bloom”. You can also find the amount of nutrients according to the mandatory NPK ratio, which you will find on the label. For hydroponic growing, use special fertilisers for use in hydroponics.

Fertilisation and plant nutrition is a complex topic that every grower should know thoroughly. If you would like to learn more, visit our Higarden blog, where we explain in detail how to fertilise plants correctly and what to do when you encounter problems during growing.