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Tips for Choosing the Right Fertiliser

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How to Choose the Most Suitable Fertiliser

STEP 1    >> KNOW YOUR PLANTS NEEDS

Does your plant have a lot of foliage?  Does it have specific nutrient needs?  Is it deciduous or evergreen?  Is it native?  If you know your plants, then you will be best prepared to choose the right Fertiliser.

 

STEP 2    >> ORGANIC, CHEMICAL OR MINERAL?

There are 3 main types of fertilisers:

Organic – natural fertilisers but usually take longer to be of use to the plant and generally do not last as long as Chemical Fertilisers.

Chemical – tend to be completely soluble, controlled release and have a higher volume of nutrients.

Mineral – (ie Dolomite Lime) are not complete fertilisers, generally do not contain all that a plant requires, but do have useful elements to correct problem soils.

 

STEP 3    >> KNOW WHAT VARIOUS ELEMENTS DO

Fertilisers often have an N.P.K. rating.  These three elements promote plant growth in three different ways. In simple terms, these are:

N – Nitrogen – Promotes vigorous plant growth for all flowers, leaves and grass.  It produces more leaves and helps produce a darker green colour by encouraging chlorophyll formation.

P – Phosphorus – Promotes healthy root and shoot growth.

K – Potassium - Promotes flowering, fruiting and general hardiness.

Mg – Magnesium - Magnesium is a component of chlorophyll pigment which gives green color to the leaves.

TE – Trace Elements - Very small quantities of compounds that are required by plants.

 

STEP 4    >> GRANULAR VS LIQUID

Fertilisers are available in various forms, but most typically Granular or Liquid.

Granular 

Advantages – Easy to measure and apply.  Less applications are required during the year. Delivers food to plants slowly.Easier not to over-fertilise.

Disadvantages – Take longer to soak in and reach roots.  Heavy rains can wash granules away.

Liquid

Advantages – Quick availability to the plants. Can be applied directly to the roots and/or foliage to produce fast results.

Disadvantages – Higher cost.  Concentrated form must be mixed with water prior to application (via watering can or hose). More applications required per year, as it works immediately and has shorter term effects.

 

STEP 5    >> UNDERSTAND RELEASE PERIOD IN SLOW RELEASE FERTILISERS

Depending on the season and the plants needs, the release period and type of fertiliser you need may differ.  Slow Release Fertilisers release nutrients according to soil temperate, access to water (osmosis) and plant uptake.

During cooler months when the plant is not actively growing, the fertiliser will last longer.  During warmer, wetter periods the fertiliser will be released more quickly.

 

STEP 6    >> 12-MONTH PLAN

It is best to try and use a combination of Slow Release (Organic or Chemical) and Liquid Fertilisers over a period of 12 months.  It is recommended to follow the application rates on your chosen Fertiliser product.

An example 12 Month Fertiliser Plan:

  • Autumn – Apply a Slow Release Fertiliser
  • Winter – Apply a Liquid Fertiliser (only if required)
  • Spring - Apply a Slow Release Fertiliser
  • Summer - Apply a Slow Release Fertiliser (and/or Liquid Fertiliser at 14 day intervals).  Especially good for fruiting & flowering trees and shrubs.

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