Fertilising your garden: What to fertilise, when to fertilise, and which ones to use?
Posted on Sunday 24th June 2018
There’s nothing quite like casting an eye over your yard to see garden beds teeming with thriving plants. Queensland’s climate, while not without its challenges, supports many species, giving us the opportunity to reap the benefits of growing healthy greenery and flowering and fruiting plants.
But because most of the plants we find blooming in Brisbane backyards and rural properties wouldn’t be found in the natural environment, they need a helping hand to fight pests and disease, and to access the nutrients they need to grow. And even when your garden is full of Australian natives, they’ll still need an extra boost, because we don’t allow them the same diet of decomposing plants and animals that they’d get in the wild.
The good news is that it’s easy to supplement your garden’s diet all year round without upsetting its ecosystem or the quality of its soil. Paying attention to a few small details can help you get the best performance from your plants, whether you’re harvesting fruit and vegetables, or simply creating a colourful and fragrant living space.
Categories of fertiliser
If it’s important to you to achieve a completely organic harvest from your garden, or you just want to use pure and natural products on your garden beds, organic fertilisers are a good choice. They’re comprised of organic plant and animal by-products without any synthetic compounds added: some examples are blood and bone, Terra Firma Poultry Manure, Organic Xtra, and Seasol (which is made of seaweed). Organic fertilisers normally release nutrients slowly, and because they’re close to what would occur in the natural environment, they’re also good at improving the structure of the soil.
Non-organic fertilisers offer extra benefits through special formulations for the unique needs of different plants and soil. Granular versions can include synthetic or ‘straight’ fertilisers with just one macronutrient (like nitrogen and potassium), blended fertilisers with different rations of NPK (like CK88), and compound fertilisers (like Nitrophoska Special) that are formulated through a chemical reaction and contain two or more major nutrients. These fertilisers are specially formulated to address nutrient deficiencies that result in poor growth and health problems in your plants.
If you’ve got more sophisticated or technical horticultural needs, soluble fertilisers may be an ideal source of nutrients for your plants. Fertilisers like Calcium Nitrate, Potassium Nitrate, Magnesium Sulphate and the GF Flowfeed range will help you deliver consistency and quality in your produce. But generally, the average garden will just need a few basic types of fertiliser, depending on the plants and conditions.
Fertilising your lawn
To achieve a soft, thick and richly coloured lawn in Brisbane, you’ll definitely need a good lawn fertiliser. But fertilising your lawn isn’t just important for improving your lawn’s health and appearance—it also goes a long way towards conserving our water supply, because it can improve your lawn’s water penetration and decrease the amount of watering it needs.
Specially formulated lawn foods (like Dynamic Lifter and Yates Weed and Feed) will do a lot to help keep weeds and pests away, and help your lawn retain its gloss and softness. But slow-release fertilisers like Osmocote and Trotoforte M will also deliver good results with their balance of trace minerals and nitrogen.
Water your lawn deeply and infrequently, but fertilise lightly and often, because big doses can result in chemicals leaking into the waterways, or your lawn ending up overloaded. Brisbane lawns seem to benefit from fertilising every 2 months or so. It’s still best to water your fertiliser into your lawn, or fertilise when you know there’s going to be rain to help absorption. Always avoid fertilising in the hottest parts of the day because it can burn your lawn, and watering too late in the day because it can cause mildew.
Fertilising citrus trees and roses
Citrus trees and roses will benefit from the same feeds and fertilisers, which makes your work lighter if you’re lucky enough to have both in your garden. They usually do well in the Queensland climate, but they’ll do better with a top up of trace elements and nutrients in the soil (you’ll notice any iron deficiencies when their leaves are pale with dark green veins).
It’s best to fertilise citrus trees and roses twice or three times a year, being careful not to overload them—because too big a dose can be harmful. Fertilise in August and February (or July, November and March), alternating fertilisers like Dynamic Lifter and CK88. Use about 125 grams for each year of their life, spread evenly throughout the drip zone (not too close to the trunks), and water it in. Seaweed emulsions are good for nourishing the soil with selenium, iodine and folic acid, which will help them to fight against fungal and bacterial infection.
Fertilising Australian native plants
Australian natives are naturally hardy, so fertilising them too much can upset the delicate balance of minerals they need to survive. Avoid using products that are high in phosphorus, and consider whether you need to fertilise them at all. But if they’re really not doing well, choose organic fertilisers like blood and bone that mimic the natural conditions they’d thrive in, or specially developed products like Osmocote Slow Release For Natives.
Fertilisers designed for Australian native plants will usually need to be watered in. While spring is always the best time to fertilise, it’s not the wet season, so you’ll need to water—lightly in the afternoon to soften the granules, and again the next morning to move it deeper into the soil, rather than one big soak.
Fertilising vegetable gardens and pot plants
Your veggie patch will do well with most all-purpose fertilisers, but it’ll also benefit from complete food formulations and soluble fertilisers. While the amount and type of fertiliser you need depends on the soil you’ve got and what you’re growing, most vegetables—particularly the leafy greens—can do with a boost of nitrogen and minerals. Vine vegetables like tomatoes and beans will only need a small amount of vegetable fertiliser, but root veggies will appreciate larger doses. Organic matter is always good for improving the quality and structure of the soil in your vegetable gardens, so poultry manure, crushed egg shells, and other kitchen scraps can be used fairly liberally and won’t do any harm to your little crops.
Fertilising is crucial for pot plants, because they don’t have access to nutrients beyond what’s in the potting mix that they’re depleting over time. Slow-release fertilisers like Osmocote are great for helping potted plants to thrive, particularly when they’re applied in the growing season (the warm months). Nitrosol (‘liquid food’)—which can also be used for shrubs and citrus trees—is great for giving both your pot plants and your veggie patch a boost of nutrition to get them started.
General tips for fertilising
One of the most beneficial things you can do to ensure your plants are getting what they need is to test the pH of your soil. You can find pH kits in your local nursery or rural supply store—they’re easy to use, and they’ll point to any deficiencies or special needs in your plants so you can find the right formulations for them.
While the beginning of spring is the most important time for fertilising your gardens and lawns, many of your plants—including citrus trees—will benefit from fertiliser to get them through the cool months, and support their immunity and protect them from pest and weed infestations.
It’s important to get the blend right—which sometimes requires troubleshooting and expertise to compensate for the harsh conditions of Queensland’s climate. If you need help achieving a good balance for your plants, ask the friendly staff at Farmcraft for help: we’ve got a huge range of organic and non-organic fertilisers, and we’ll be happy to help you find the right formulation to keep your garden blooming.
