Your Guide to Fertilisers

What is the purpose of fertiliser in the garden?

Like humans, plants require food, water and sunlight to flourish. They obtain the majority of their nutrients directly from the soil, including the big three, nitrogen (N), potassium (K), and phosphorus (P), plus a whole heap of other minerals and trace elements.

In most garden soil and topsoil, this is in limited supply and over time they will be depleted either by the plant or leached out by watering or weather. The use of fertilisers is a way of supplementing the nutrient supply within the soil as this occurs.

When should you fertilise?

Most plants will benefit from a good feed of fertiliser once every season. We recommend starting with this type of routine and watching how your plants respond. If required, you can give them a mid-season boost by supplementing with a liquid fertiliser such as UltraGrow’s Dyna-Maxx Pure Seaweed or worm castings.

The most important time to feed your plants is during the spring as this is when your garden is waking up from winter dormancy and new growth starts to appear. We recommend using Sonic Bloom as well as it’s scientifically designed to promote healthy buds, flowers, and fruit.

What type of fertiliser to use?

Fertilisers are generally available in granules/ pellets or liquid form. Liquid is great as it can be applied to the soil directly or to the foliage of the plant. To decide which type is right for you, make sure to read the label carefully and ask your nursery or landscaping professional for some advice. The next section lists key things to be aware of and the questions you should ask.

Is it certified organic?

If you are growing food and intend to keep your soil healthy, organic fertiliser is the only choice. Organic fertilisers are usually derived from such things as cow manure and organic based compost (organic in origin such as plant material). So, keep an eye out for certified organic products or fully organic based options.

Remember, what you put in is what you get out, so keep that in mind when choosing fertilisers for the soil. This concept also extends to the quality of your starting soil mix. When importing new soil to start a garden bed or top up an existing spent bed, investing in quality garden soil is imperative. Centenary Landscaping Supplies manufactures a range of truly premium soils and potting mixes called the UltraGrow Collection. These soils are scientifically blended using the best quality ingredient and come pre-loaded with fertiliser to give your plants the best possible start in life. Remember, what you put in your get out.

What is the NPK ratio?

This ratio helps you choose a fertiliser specific to a plant’s needs. Nitrogen is responsible for foliage growth and chlorophyll production. Phosphorus is needed for healthy root growth and overall growth. Potassium promotes flower development.

This basically means:

• For a garden with lots of flowers choose a fertiliser high in potassium.
• For a veggie patch with lots of root vegetables choose a fertiliser high in phosphorus.
• For a garden with lots of green foliage choose a fertiliser high in nitrogen.

Is an all-around fertiliser right for my garden?

Unless you want to feed a specific type of plant or know exactly what your soil needs at a particular point in time, an all-round organic fertiliser is a reliable option. You can add soil conditioners such as seaweed extract, worm casting and rock dust to the mix too.

How much do I apply?

How much fertiliser you need to apply depends on the type of fertiliser and the size of your garden bed, veggie patch or pot plant. The safest method is to follow the instructions on the packet; this will guide you about quantities and any preparations needed.

Remember that you are growing soil first and plants second. So, think carefully about what you are putting in the earth.