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Shovel digging into soil.
Just like people, plants need nutrients to thrive, but which fertilisers or soil mixes should you use? Let’s unearth the options.

Don’t skip out on soil health

If there’s one secret to bigger blooms or juicier fruit, it’s this: you need to feed! “Plants need access to a range of nutrients for growth and development, and applying fertilisers will help,” says Angie Thomas of The Happy Gardener (@angiethehappygardener). It’s just as important to nourish the soil. “Good quality soil provides the foundation for healthy root development and plant growth,” says Angie.

Get the dirt

Soil improvers and fertilisers are not one and the same. Bagged compost, manure and garden soil are considered sources of organic matter and perfect soil amendments. They are used to enrich the soil, which, in turn, provides plants with the support they need for growth. “Mixing rich sources of organic matter into the soil increases water- and nutrient-holding capacity, improves structure and drainage, and encourages earthworms and beneficial soil microorganisms,” says Angie. It’s incredibly beneficial for your soil and plants to consistently improve the soil, especially if you have sandy or clay-based soils. “Mix them into the soil prior to planting or lightly blend into the top soil between seasons,” adds Angie.

Soil improvers need to know

Compost: a great source of organic matter, typically made from composted green waste and other decomposed organic materials. Mix into garden beds and potting mixes.

Manure: contains plant nutrients, which are slowly released in the soil. Purchase bagged manure, rather than fresh, as it’s well composted, so won’t burn your plants. Dig well into garden beds prior to planting.

Blood and bone: mostly made up of animal meal and composted manures, with a small amount of nutrients to gently feed plants, while improving soil.

Bagged soil: ideal for filling new garden beds or topping up existing beds. An organic soil blend, typically enriched with slow-release nutrients.

metal outdoor setting in a cottage garden

Feed with fertiliser

Soil improvers do contain very small amounts of nutrients but don’t have all the necessary elements to provide plants with a well-rounded diet. Fertilisers, on the other hand, contain a blend of nutrients that directly affect plant growth and development and therefore are essential for a productive garden. “It’s important to use a complete fertiliser, which contains nitrogen (N), phosphorus (P) and potassium (K),” says Bunnings garden care buyer Matt Wagner-Smith. Fertilisers are available in various forms, including pellets, liquid, powder and granular, all with varying feed times. “Gardeners can choose what format best suits them depending on how much time they spend in the garden and how familiar they are with the range of products available,” says Matt.

Liquid foods are generally fast-acting and need to be applied regularly throughout the season, whereas pelletised foods are generally slower release and longer lasting, so are needed only a handful of times throughout the year.” Always check product labels to know when and how much to apply. Fertilisers may also be organic, organic-based or inorganic (synthetic). Regardless of their nature, they all provide nutrients to support plant growth and improve soil health.

The lowdown on fertilisers

Organic-based fertilisers: contain organic and inorganic elements to slowly release nutrients and improve soil health, with fast-acting soluble nutrients for plant growth. For vegans, try Yates Vegan fertiliser, which has no animal ingredients and can be used on indoor and outdoor plants.

Controlled release: available in coated prills (small, bead-shaped pellets), which break down to release nutrients when the soil temperature increases. They can keep feeding targeted plants for anywhere between 3-12 months and are suitable for most areas of the garden.

Organic: often made of animal by-products, with added seaweed and organic matter to provide plants with a gentle feed. Look for Dynamic Lifter or Charlie Carp, which are suitable for all plants.

Slow release: contain nutrients that are broken down by microbes and dispersed into the soil over a longer period of time for a consistent feed.

Soluble and liquid: quick and easy to mix for application – simply dilute with water and use as recommended when watering. This is a fast way to deliver nutrients, especially when plants are actively growing, flowering or fruiting. Use for pots, garden beds and indoor plants.

Specialised: available in various formats formulated with the right balance of nutrients for specific plant types; for example, flower and fruit fertilisers will have higher amounts of potassium, while leafy greens and herbs will have higher amounts of nitrogen.

More information on how to improve your garden beds

Check out the range of potting mixes, composts, mulches & manures to boost your garden soil.


Health & Safety

Please make sure you use all equipment appropriately and safely when following the advice in these D.I.Y. videos. You need to be familiar with how to use equipment safely and follow the instructions that came with the equipment. If you are unsure, you may feel it is safest to consult an expert, such as the manufacturer or an expert Bunnings Team Member.

Grave health hazards are linked to asbestos, which may be in homes built up to 1990. Health hazards may result from exposure to lead-based paints in older materials and copper chromium arsenic (CCA) treated timber. For information on the dangers of asbestos, lead-based paint and CCA treated timber and tips for dealing with these materials contact your local council's Environmental Health Officer. You can also use a simple test kit from Bunnings to indicate the presence of lead-based paint.