- Synthetic fertiliser releases nitrogen and other nutrients into the soil quickly which can give a boom-and-bust type of growth, while organic fertiliser releases nitrogen slowly, ensuring farmers a more stable and steady growth period.
- Organic fertilisers promote natural nutrient storage mechanisms in the soil which help micro-organisms to grow. These critters break down organic materials to keep nutrients in the soil and because of this effect, you will need to fertilise less often.
- Using organic fertiliser helps the soil to retain moisture, reducing the need to water.
- Organic materials help to maintain the structure of the soil and prevent erosion.
- Environmental effects are minimised because one does not need to use organic fertilisers frequently. Commercial fertilisers need to be used in large quantities to be effective. Excess nutrients run off into waterways and cause a detrimental process called eutrophication — the growth of algae which suffocates fish and other life in water.
- Depending on where and how you get the organic fertiliser, it may be less expensive than the synthetic one.
Fertilising organically is not perfect. It presents more advantages over synthetic fertilisers, but it has a
- The composition of organic fertiliser is often more complex than a synthetic product. It may require more consideration and testing of soil to determine what types of fertiliser and how much is needed for your garden.
- An organic fertiliser that is improperly produced may contain harmful pathogens. If you plan to make your own, be sure that you know how to do so correctly. These pathogens could be harmful to people, animals and plants.
- Using organic fertiliser is much more labour intensive. It requires more care and effort to use.
Types of organic fertilisers
There are two main types of organic fertiliser: animal and plant.
Some would also call rock and mineral fertilisers a third type of organic product but technically it is not organic.
Plant-based fertilisers include compost, alfalfa, cottonseed meal, soybean meal, wood ash and kelp or seaweed.
Compost is something you can easily make yourself and it is a great way to recycle waste.
However, compost made only from plant material often does not have enough nutrients. It may need to be supplemented with other fertilisers.
The plant meals provide the important macro-nutrients, while kelp has many trace nutrients. Wood ash provides a lot of potassium, but also alters the pH of the soil.
Animal-based fertilisers include livestock manure, fish meal, blood meal and bone meal.
Blood and fish meal provide plenty of nitrogen. Fish also provides a lot of trace nutrients.
Bone meal contains a significant amount of phosphorus and manure offers all of the macro-nutrients. Manure that is fresh can harm plants, so be sure to compost it properly before using as a fertiliser.
Make them yourself Some of the organic fertilisers you may wish to try can be easy to make yourself. For instance, as a farmer, you probably already have a compost pile. To enhance your use of compost as a fertiliser, you may want to think about composting your livestock manure.
Learn from other farmers or books on how to do it correctly to avoid damaging your plants, though.
Adapted from online sources