Maintaining a glorious garden brimming with scented flowers and vibrant foliage is easy - just give plants what they want:
- Water
- Sunlight/Shade
- Nourishment
You’ve already chosen their positions and you know how to wield a hose, but how do you make sure they have all the nutrients they need to develop strong roots, masses of flowers and lush foliage?
By using fertilisers, of course!
Let’s take a look at what you need to know to select the right fertiliser for your garden, including:
- Types of fertilisers
- Understanding fertiliser ratios and NPK
- What fertiliser to use and when
- The importance of soil pH
What you need to know about fertilisers
The type of fertiliser you choose will have a huge impact on the health of your garden. There are lots of options available, and choosing the right one at the outset can save you time and money in the long term.
Types of fertiliser
The most common types available:
- Organic based - either certified 100% organic or including organic matter.
- Composts and soil improvers.
- 'Instant hit' powder, granular and liquid fertilisers.
- Slow-release fertilisers.
- Controlled release fertilisers.
Learn more about the frequency, pros and cons of each.
The benefit of Osmocote slow release fertiliser
The benefits of Scotts Osmocote Controlled Release Fertilisers, include:
- Easy to apply
- Feeds for up to 6-months
- Releases nutrients only when plants need them - more when it's warm and plants are growing and less when it's cold and growth is slow
- Scotts Osmocote® uses advanced prill technology that ensures even and controlled nutrient release with no wastage
- Wetting agent improves water absorption, helping plants take up nutrients
- Less excess and leaching, helping keep our environment healthy
Understanding fertiliser ratios and NPK fertilisers
Fertilisers are combinations of essential elements (nutrients) that have been mixed at specific ratios to encourage plants to grow, flower or fruit.
- Fertiliser manufacturers list these ratios on the packets, usually shown as N:P:K or Nitrogen (N), Phosphorus (P) and Potassium (K). These are the macro or major chemical elements that directly impact plant growth and development.
- Plants also require micro nutrients and trace elements to maintain optimal health. To see what these are and why they are important to plants, look at Fertiliser Components and their Uses.
Most fertiliser packaging will include a Guaranteed Analysis that lists all major, minor and trace elements included and their relevant percentages or parts per million.
The importance of soil pH
- The pH of your soil determines the availability of some nutrients
- Test your pH every three to four years and adjust accordingly
- pH should be between 5.5 and 6.5 for most flowering trees and shrubs.
To find out more about soil pH and healthy soils read our story How to establish a new garden bed.
What fertiliser and when
Different fertilisers are required at different stages of plants' lifecycles. Whether it's establishing a new tree or encouraging more flowers and fruit, there's a fertiliser to suit each stage of growth and development
Choosing the best fertiliser for your plant type
High nitrogen fertilisers for young and newly planted trees
What: Use a high nitrogen fertiliser to help develop strong growth.
Note: Additional applications of chicken manure will also be of benefit.
Acidic fertilisers for acid-lovers like gardenias, camellias, roses and blueberries
What: Use a fertiliser like Scotts Osmocote Controlled Release Fertiliser for Roses, Gardenias, Azaleas & Camellias which has been specifically designed to give acid-loving plants the nutrients they need to flourish.
Note: Use a controlled release fertiliser to ensure the right nutrients are available at the right amount for your plant.
Native fertilisers high in phosphorous for native trees and shrubs
What: Use a fertiliser designed for phosphorus sensitive plants.
Note: Native plants may be hardy, but they still need feeding. As they are accustomed to phosphorus-deficient soils, ensure that you feed them with low P fertilisers.
High potassium fertilisers for flowering plants
What: To encourage flowering, most plants benefit from a fertiliser high in potassium, like Scotts Osmocote Pots & Planters Controlled Release Fertiliser. This is best applied at the start of Spring and Autumn. Use a liquid
Note: Use an all-purpose controlled release fertiliser twice a year, and apply liquid feeds throughout spring and summer for maximum wow!
No fertilisers for dormant (deciduous) trees and shrubs
What: Do not fertilise them while they are devoid of leaves!
Note: Wait until the first signs of new leaves and flowers appear in Spring before fertilising.
Additional fertilisers
What: Our range of fertilisers will improve plant health as well as pest and disease resistance.
Note: Liquid fertilisers help to give plants an instant boost as they contain a mix of macro, micro and trace elements.
