An overview of the types of fertilizers available today.

This page will ‘un-confuse’ you by explaining clearly and simply, what the main types of fertilizer are.

Your First Choice

Fertilizers fall into one of 2 types depending on whether they get into the plant through the roots or the leaves.

Soil-Applied

Fertilizer applied to the soil in which the plants are growing. It mixes with rain and dissolves into the soil solution to be taken in by the plant roots.

Can be very wasterful because only a small percentage of the fertilizer is taken into the plants, with the remainder either remaining locked in the soil or leached away into groundwater where (particularly in the case of nitrates) serious pollution results.

Foliar

Fertilizer sprayed onto the leaves of the plants. It is transported through the plant’s vascular system.

Far more efficient than soil-applied because up to 90% of the fertilizer is absorbed by the plant. Pollution is therefore also virtually nil.

Your 2nd Choice

Fertilizers are either based largely on natural processes (Organic) or based largely on man-made processes (Synthetic).

Organic Fertilizers

This includes manure, slurry, worm castings, peat, seaweed, sewage, guano, green manure crops, mine rock phosphate, sulfate of potash, limestone, compost, bloodmeal, bone meal,fish extracts, seaweed extracts, natural enzyme digested proteins, fish meal, feather meal and decomposing crop residue.

These types of fertilizers are far more likely to result in a sustainable outcome because they tend to improve the soil as well as nourishing the plants. Therefore over time the soil fertility and structure improves rather than degrades.

That makses sense because this type of fertilizer is far closer to what happens in nature, which is of course the most sustainable system for growing plants that we have here on earth!

Synthetic Fertilizers

Manufactured mainly from inorganic materials, often called Chemical fertilizers. These are based on Von Liebig’s idea that all you need to do to promote plant growth is replace the inorganic elements that are missing from the soil. Many synthetic fertilizers replace just one of these elements at a time.

The most important are:

• Nitrogen(N) – Urea, Ammonia
• Phosphorous(P) – Phosphate Rock, MAP, DAP
• Potassium(K) – Potash(KCL), K2SO4, potassic super

Unfortunately these fertilizers, despite their wide use, do not do anything for the long term health of the soil and are therefore not regarded as sustainable.