Plants don’t need much to be happy.

Sunlight, water and food are pretty much all that’s necessary for them to thrive and provide us with delicious homegrown produce. As long as you have chosen a nice sunny spot in the garden and go for the odd wander with a watering can or hose, the first two are taken care of – but providing your plants with all their nutritional needs is where things can get a little more involved.

Unless you’re lucky enough to live somewhere with abundant volcanic soils or on the alluvial flats of an ancient flood plain, in Australia, chances are that you’re dealing with average-to-poor soils to grow your food. Of course, plant nutrition starts with building up your soil through the addition of compost, worm castings and well-aged manure, but we can also give our plants a little nutritional boost through the growing season by watering them with a diluted natural liquid fertiliser.

There are plenty of liquid fertilisers that you can buy from hardware stores and garden retailers, though in true DIY frugal gardener fashion, you can easily make your own for next to nothing.

Here are three simple natural fertilisers for you to try making. All you’ll need is an old pillow case that you’re happy to sacrifice to the cause, a 20 litre food-grade plastic bucket, and weeds, aged manure or seaweed.

Weed tea

What happens to all the weeds that you pull from your garden? Weeds are excellent miners of minerals from the soil, and while they can be composted or fed to the chooks, they also make excellent source material for a homemade fertiliser tea.

The next time you’re weeding, shake any soil off the root balls, then stuff the pulled weeds into the pillow case. Once the pillow case is full, tie a knot in the top and pop it in the bucket. Fill the bucket with water and let it steep for at least 2 weeks.

After that, you can use it to water the garden by diluting it to one part weed tea to 10 parts water. Once the weeds have decomposed, feed them to the worms or the chooks, or pop them on the compost heap.

Manure tea

If you live in a semi-rural area surrounded by farms, you should be able to track down some aged animal manure to use in your garden. Adding manure directly to the soil can be too rich for your tender plants – it could burn them or introduce weeds into your immaculate, weed-free beds.

By using the manure to make a ‘tea’, you can gain all the nutritional benefit with none of the risk. All you need to do is stuff your pillow case ‘teabag’ with the aged manure, pop it in the bucket and fill the bucket with water.

Let the tea steep for two weeks, then dilute the liquid in a ratio of one part manure tea to 15 parts water. After you’ve used the liquid, simply add the leftover manure to your compost.

Seaweed tea

If you count yourself among the many Australians who live within a short drive to the coast, the next time you visit keep your eyes open along the sandy stretches for washed-up seaweed.

Seaweed is loaded with all kinds of micronutrients that make an excellent tonic for plants. But before you take the trailer down to your local beach, make sure you check with the local authorities for any restrictions around collecting seaweed, as most shire councils will have some rules about where you can collect it and how much you can take.

Break out the trusty pillow case ‘teabag’ and fill it up with seaweed (I don’t even bother rinsing it as the levels of salt will be negligible, but you can give it a quick rinse with fresh water if you like). Pop the pillow case into your bucket, then fill it up with water and let it steep for around a month. Once it’s brewed, dilute the liquid in a ratio of one part seaweed tea to 10 parts water.

• This is an edited extract from Homegrown by Paul West, published by Penguin Australia (RRP$17.99).