How To Make Homemade Fertiliser For Native Plants

Native plants are perfect to grow in Aussie gardens; they’re ready-built to thrive in our climate and environment. Native Australian plants are excellent choices for any garden, and there’s a wide variety available to cultivate. Of course, like all other plants, there’s plenty that goes into native plant care, including pruning, watering — and fertilising.

To make a homemade fertiliser for native plants, DIY organic mulch or compost is best. You can create homemade mulch from low-phosphorus organic matter such as pine bark or blood meal, or use manure compost or clippings from street trees. Just check the phosphorus requirements of your plants first.

So now — why does phosphorus matter, how does it affect native plant fertilisers, and how do you fertilise your native plant garden?

Special Considerations for Homemade Native Plant Fertiliser

The common belief that native plants shouldn’t be fertilised comes from the fact that they naturally thrived in low-nutrient soils — particularly, soil low in phosphorus. But according to the Australian Native Plants Society (ANPSA), it’s perfectly fine to apply general purpose fertiliser to many native plants in slow-release form. This allows for a more gradual release of nutrients into the soil and lets your plant adjust accordingly.

The most notable exception to this is Proteaceae plants (such as banksia, grevillea, hakea, and waratah), which have developed specialised roots called “proteids”. These roots spread out in a fine mass of small “rootlets” which allow the plant to absorb nourishment from nutrient-deficient soil. Fertilising using general purpose products could end up causing the plant to take in excess nutrients, which is toxic to its development. Acacias, bossiaeas, and petrophiles are also sensitive to phosphorus.

ANPSA recommends you use low-phosphorus fertilisers (with a nitrogen:phosphorus:potassium ratio of 10:3:6, or a ≤3% of phosphorus) for more sensitive species. Otherwise, regular fertiliser (that with an N:P:K ratio of 12:14:10) is safe to use — again, just control the release!

How To Create Homemade Mulch

Mulch is an excellent fertiliser to use on native plants since it breaks down slowly over time, gradually releasing nutrients into the soil. When using organic matter such as leaves and bark, try not to shred too fine — the larger the chunks, the slower they’ll break down. To make homemade garden mulch, you’ll need:

  • Organic materials from your garden (grass clippings, leaves, twigs, and bark)
  • Lawn mower or wood chipper

NOTE: Leaves and grass clippings are best taken after mowing your lawn so they’re roughly shredded. You can mow the lawn yourself with a bag attachment, or get a professional mowing service to mow and collect the material for you!

FOR GRASS AND LEAF MULCH:

Collect grass clippings and raked leaves into a pile in a corner of your garden. Check for any diseased or moulding leaves and remove them. Then run them over with a lawn mower a few times to shred them and mix them up.

leaf mulch for native plant fertiliser

You can either layer the shredded clippings around your native plants as-is, or compost them in a bin. Take note: if you go the bin way, you’ll have to wait a few months for your mulch to be ready. Try mowing ahead of winter so that your mulch is ready for mid-spring!

FOR BARK MULCH:

Pine bark is particularly good for native plants since it’s low in phosphorus, but you can use most other kinds of wood too. Take your bark and chips, and run them through a wood chipper to break them down further. Don’t shred too fine, since that’ll cause it to break down faster. Then layer the bark around your plants and let it work!

It’s important not to use mushroom-based compost or mulch — this could raise soil pH, which is detrimental to native plants.

Using Blood Meal Fertiliser

It’s important to use blood meal, not bone — bone meal fertiliser is high in phosphorus, which your plants won’t really need. This is a tricky fertiliser to DIY, so you may be better off purchasing a commercial form. But if you’re willing to try on your own, boil the blood while stirring constantly. When the moisture has reduced around 10–12%, and the mixture is considerably thicker, spread it out on a clean surface. Then dry either out in the sun or in an oven.

Blood meal fertiliser is also water soluble, so you can dissolve it in water and mix it in your compost, too.

Avoid excessive application of this fertiliser since it’s high in nitrogen — another nutrient that native plants don’t need too much of!

Is Chicken Manure Good For Native Plants?

Yes and no. Of all manure fertilisers, chicken manure has the highest percentage of phosphorus, so it’s not suitable for native plants that are sensitive to that particular mineral. Avoid using poultry manure-based fertiliser on native Proteaceae plants or acacias. Otherwise, you can either get a manure pellet fertiliser specially formulated for native plants, or make some manure tea on your own.

(Yep, that’s what it’s called.)

How To Make Homemade Manure Fertiliser

Ready to get down and dirty? DIY manure fertiliser also works well for native plants. Many commercial manufacturers use poultry manure as a base for their fertilisers, but you can opt for pig, horse, or cow manure to lower the phosphorus content.

In a large container, mix your manure with water in a ratio of one part manure, two parts water (or ⅓ manure, ⅔ water). Let it ‘steep’ for a day or two, while stirring occasionally. When it’s done steeping, let the solid particles settle at the bottom so it’s easier to filter them out. You can strain the mixture into another container, or just grab a bucket as needed.

Alternatively, you can DIY a ‘tea bag’ with some cheesecloth or an old pillowcase. Fill the makeshift ‘bag’ with the same ratio of manure (one part manure to two parts water) and steep it in water. Then you can lift the bag out, and even recycle the steeped manure as compost or additional fertiliser!

How To Fertilise Australian Native Plants

When applying organic matter such as compost and mulch to native plants, make sure to layer away from the base so you don’t smother the plant. It’s also better to layer mulch on top of soil instead of mixing since this further slows the release of nutrients into the ground.

If you’re going to improve your soil alongside the fertiliser, avoid lime and dolomite since these could make the soil too alkaline for native plants. Gypsum is a better option since it doesn’t affect the pH balance of the ground.

Seaweed-based fertilisers are also good for native plants!

And as always, before fertilising, check if your plant needs it. A visual assessment of the leaves is usually enough to tell whether your plant needs a boost or not. Aussie native plants are usually happy being left alone to thrive since they developed in soils with poor nutrition. Still, that doesn’t mean they don’t appreciate a little help sometimes!

If you enjoyed reading this blog, check out our other gardening articles such as Does Cutting New Grass Help It To Grow? or How to Sharpen Ride on Mower Blades.

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Did you know that Experteasy in Sydney can help find local garden services and make the process of finding a gardener easy.

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