Why Fertilise?

• Some plants, such as fruit trees, vegetables and roses, have been bred to be super productive and need extra. Lawns are other good examples. Every time the lawn is mowed and the clippings removed, the plants have to begin re-growing their leaves again. It is important to be aware that fertilisers are not ‘food’ for plants – plants manufacture their own sugars from the sun – but are necessary to enable plants to function effectively. However, generally, the term ‘plant food’ is commonly used when referring to fertiliser.

• Nitrogen (N) - Nitrogen is an essential part of the proteins in plant cells. It is most important for leaf growth and is a necessary part of the green pigment chlorophyll.

• Phosphorus (P) - Phosphorus is imprtant in cell formation so is most needed by the growing parts of the plant. Phosphorus promotes the development of seedlings, root growth, flowering and formation of fruits and seeds.

• Potassium (K) - Potassium assists in photosynthesis and is helpful to the plant’s ‘food factory’. It assists the plant’s overall strength, water uptake and disease resistance, and improves the quality of flowers, fruits and seeds.

2. Minor Elements

• Calcium (Ca) - Calcium forms the cell wall structure. It is available in lime, superphosphate and gypsum but is quickly leached out by heavy rain. Watch out for blossom end rot (sunken areas on the base) on fruits, especially tomatoes. This is caused by lack of calcium or by poor uptake of calcium which may be a result of unreliable watering.

• Sulphur (S) - Sulphur forms part of plant protein. Deficiency is relatively rare because sulphur is found in most plant foods.

• Magnesium (Mg) - Magnesium is important in photosynthesis because it is present in chlorophyll. New leaves have first call on this nutrient and, because magnesium moves very readily through the plant’s system, deficiency is most often evident as yellowing of the older leaves. A magnesium boost is supplied by an application of Epsom Salts dissolved in water.

• Trace Elements - Iron, Manganese, Zinc, Copper, Boron, Molybdenum.

• Don’t apply any fertiliser until you have read the directions carefully.
• Don’t try to apply one or two year’s supply of fertiliser at the one time. It is far better to provide little and often; trying to get fast growth by a heavy application is a recipe for plant failure.
• Don’t fertilise into dry soils. To avoid damage to feeding roots, make sure that the soil is moist by soaking before and after the application.
• Don’t apply fertiliser to a lawn and then neglect to water it in very thoroughly, especially in hot weather. It is inevitable that leaf burn will occur with careless applications of fertiliser on lawns.
• Don’t fertilise ferns with anything except organic based fertilisers such as fish emulsion and blood and bone.
• Don’t fertilise Australian native plants with fertiliser containing a lot of phosphorus. Whilst many Australian natives accept reasonable quantities of phosphorus, there are many that resent high phosphorus levels.
• Don’t continually fertilise lawns with sulphate of ammonia, as it encourages excessive top growth but reduces root development and eventually makes for a weaker lawn. It can also alter the soil pH level towards acid conditions (which grasses don’t like). It is okay to apply the occasional feed with sulphate of ammonia providing there are follow up applications of a complete lawn food.