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Fertilising your garden the natural way


1st Jan 2015 Home & Garden

Fertilising your garden the natural way

To germinate, grow, flower and set seed, plants need 16 essential elements, from the air, water, but mostly soil. Organic fertilisers such as animal manures, vermicompost, chicken manure and seaweed are all good earth-wise fertilisers and they are all either cheap or free.

How to use fertilisers

Always thoroughly water garden beds before and after fertilising, otherwise the fertiliser may damage plant roots. Conserve water and save money by fertilising your garden during periods of heavy rain.

Fertilise plants in the warmer months of the year, when they are actively growing. In the cooler months they are dormant and don’t need much food, so save money by not using fertiliser in winter. Fertilise lawns twice a year, during spring and autumn.

Follow the directions on the fertiliser container—some plants, such as ferns, only require half-strength applications.

Learn which plants need a large quantity of fertiliser. These plants are known as ‘gross’ feeders and include citrus, roses, hibiscus, bougainvilleas, gardenias, lawns and most vegetables.

Add slow-release fertilisers—they’re safe to use and won’t burn plant roots. For a quick boost, consider using a leaf fertiliser.

The essential fertilisers are nitrogen (promotes green growth), phosphorus (for general health) and potassium (for fruit and flower development).


Animal manures

These contain all the basic plant nutrients and add bulk fibre to the soil. They also encourage beneficial organisms such as earthworms. Apply them as mulch or dig in to improve the soil.


Chicken manure

This provides all the basic plant nutrients and makes a good mulch around plants that require lots of fertiliser. Freerange chickens add the manure directly to the garden.



This contains naturally occurring hormones that stimulate root growth. Seaweed helps to minimise transplant stress and provides better tolerance to cold and heat. Some kelps are low in nitrogen. Before collecting seaweed, check with the local council to find out if it is legal to do so.


Compost heap

Plants get most of their nutrients from compost, which is decomposed organic matter in the soil. By making your own at home you can help boost the health of your plants and help the environment by reducing waste in the home.


Vermicompost (worm castings)

As well as being an excellent fertiliser, vermicompost (worm castings) is great for other jobs in the garden. Use it as a soil conditioner, garden mulch, top dressing for lawns and in seedraisingand potting mixes. Dilute it in water (until it becomes the colour of weak tea) and use it on potted plants.


Build your own worm farm


A worm farm is small enough to be kept on a balcony, so if you have a limited amount of space, it’s ideal for producing your own fertiliser. Here’s how to build your own.

1. You’ll need a moisture-proof container that is 30 centimetres deep with drainage holes in the base, bedding (in the form of straw or shredded newspaper), water and some kitchen scraps.

2. Place some bricks in a tray and sit the container on the bricks. Excess liquid from the worm farm will fall into the tray.

3. Fill the container to about three-quarters full with bedding, moistened to the consistency of a damp sponge. Add a little soil or sand to help the worms digest the waste. Leave it to settle for a couple of days.

4. Introduce tiger worms (Eisenia fetida), available from worm farms or the Internet. Or ask at your local hardware store or nursery. Don’t use worms from the garden as that type prefers ordinary garden soil and won’t thrive.

5. Loosely cover the box with a sheet of plastic or sacking. If you keep your worm farm outdoors, a container with a lid is best.


How to use animal manures

Check the horse manure you obtain from stables. If it contains lots of wood shavings, it will take longer to decompose. If you find grain seeds, just think of them as green manure – when they sprout, simply pull the seedlings out and throw them on the compost heap.

Allow cow manure to rot down before you use it on the garden. Milled cow manure is available by the bag from nurseries.

Chicken manure is very strong, so age it for at least six weeks before you use it. If you don’t keep chickens, you can buy the manure from garden centres. Make sure it’s from a free-range poultry farm if you disapprove of battery or deep litter poultry farms (the litter is not changed for weeks).