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Australian Guide to Vegetable Fertilisers

If you’re new to growing your own vegetables, fertilisers and which ones to use can be quite overwhelming.

In this guide, I’m going to help you out in your vege-growing journey by discussing what fertilisers do, and their most essential components.

Plus, I’ll provide you with some recommended vegetable fertilisers and some tips on easy ways to get started.

What is a fertiliser?

Lawn Fertilizer | Fruit & Vegetables

In general, a fertiliser is a product that contains the essential nutrients that your vegetables need to grow and to fruit. Most fertilisers that are good for vegetables will have three essential nutrients. These are nitrogen, phosphorus, and potassium. You’ll find these are labeled as N:P:K on most packaged fertilisers.

Essentially, all plants need these three nutrients to grow successfully. Nitrogen stimulates green growth. It is essential for all vegetables but is needed in greater quantities by leafy greens such as lettuce, spinach, and kale. That’s because it’s the green leaves that we harvest from these vegetables for our food.

lettuce growing in vege garden | Fruit & Vegetables

Phosphorus is equally as important because it helps plants to produce a healthy and vital root system. Not only do roots support your veggies but they also gather the nutrients from the soil and transport these up the plant to feed the growth. Think of the plant’s internal transport system like the veins in our body that transport blood around.

The last major essential nutrient is potassium. This is the one responsible for encouraging your plants to produce flowers and fruit. Therefore, it’s required in greater amounts for fruiting veggies such as tomatoes, capsicums, and cucumbers.

Tomatoes in Melbourne 3 | Fruit & Vegetables

So, now that you know the basics about what these major nutrients do, how do you ensure that you give the right ones to your veggies? And, do you need different ones for different vegetable plants?

What are the different types of fertilisers?

There are basically two different types of fertilisers (organic and inorganic) and these can be available either in pellet or liquid form. 

In addition, there are also products that are classified as soil conditioners. These help to enhance the health of the soil and the plants.

Inorganic fertilisers

Inorganic fertilisers are manufactured using chemicals to include a variety of different nutrients for optimum plant growth. They can come in either pellet or liquid form and there is a wide variety available on the market today.

Fertiliser 1 | Fruit & Vegetables

Although these are popular, the problem is that they don’t improve soil health. And, if they’re used in large amounts, they can often burn the roots of the plants and increase the salt levels in the soils. They can also leach out of the soil after heavy rain and end up in our natural waterways.

Organic fertilisers

I’m a firm believer in using organic fertilisers in my garden. That’s because these products are natural and also help to keep the soil healthy. And, healthy soil produces healthy plants.

The ones on the top of my list are Dynamic Lifter and Blood and Bone. Both of these products are based on animal products such as poultry manure, blood meal, and bone meal. Here’s the N:P:K breakdown of each product:

  • Dynamic Lifter 3.5:1.0:1.6
  • Blood and Bone 8.0:1.6:1.5

These are the ideal ratios for growing healthy vegetables of all varieties.

Soil Conditioners

Soil conditioners include products like compost, animal manure, seaweed concentrates, and fish emulsion. Generally, you would add compost or animal manure to the soil before planting to help break up heavy soils and aid in water retention. These also help to increase healthy microbial activity in the soil that assists in healthy root growth.

Products like seaweed concentrate and fish emulsion usually come in liquid form and these can be watered into the soil during plant growth as a general tonic.

Feeding your vegetables doesn’t have to be confusing

If you’re just beginning your vegetable-growing journey, don’t get bogged down by all the different types of fertilisers available. You don’t have to buy one type of fertiliser for your lettuce and a different one for your tomatoes

If you use a general-purpose organic fertiliser like Dynamic Lifter, or Blood and Bone, and add some compost to the soil before planting, you’ll be able to grow all the vegetables that you want.

The best thing about organic fertilisers like Dynamic Lifter and Blood and Bone is that they contain the three essential nutrients as well as many trace elements like iron and magnesium that your plants need for healthy growth.

These types of fertilisers are also slow-release and are easy to scatter around the plants onto the soil. Once you water, the pellets will work their way down into the soil and the nutrients will be released to the plants via the roots as they need them.

Another advantage of this is that you only need to apply these once during the growing season as they’ll continue to feed the plants and will generally last 4 to 6 months.

To give your plants a boost, especially if you’re growing fruiting crops, get yourself some Seasol or Charlie Carp and apply this in liquid form once every two weeks or so.

Charlie Carp | Fruit & Vegetables

Make sure you mix these with water as per the recommended dosages on the pack.

Vegetable Fertiliser FAQ

When should I fertilise my vegetables?

Vegetables should be fertilised during their main growing season. This means you would fertilise summer-growing vegetables during spring and winter-growing vegetables in autumn.

How often should vegetables be fertilised?

If you’re using an organic fertiliser in slow-release pellet form, you only need to feed your vegetables once during their main growing season. Follow this with a fortnightly application of liquid seaweed or fish emulsion.

Why are my vegetables not growing big?

There are a number of factors that can retard the growth of your vegetables. Primarily, they are not getting enough sun, the soil is poor, waterlogged or heavy clay or you’re not giving them enough water during the hotter months. Most vegetables should be grown in full sun and in relatively friable soil that has been enriched with compost.

Photo of author

Annette Hird

Annette Hird is a gardening expert with many years of experience in a range of gardening related positions. She has an Associate Diploma of Applied Science in Horticulture and has worked in a variety of production nurseries, primarily as a propagator. She has also been responsible for a large homestead garden that included lawn care, fruit trees, roses and many other ornamental plants. More recently, Annette has concentrated on improving the garden landscape of the homes that she has lived in and focused a lot of energy on growing edible plants as well. She now enjoys sharing her experience and knowledge with others by writing articles about all facets of gardening and growing plants.

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