How to Grow Tomatoes

Tomatoes fall into two main types: determinate or ‘bush’ tomatoes and indeterminate or vining tomatoes.

Determinate Tomatoes generally grow to about 0.5-0.6 m tall (some over 1 m tall) and produce fruit that mature all around the same time (generally over a 2-3-week period). Once they have finished fruiting, the plant will not continue to produce and will slowly decline in vigour, so it’s best to remove once they’re done. Due to their height, they don’t require staking, but you can prop them up with stakes or a cage made from sturdy chicken wire. This is particularly helpful in windy sites or if the plant is heavily laden with fruit. These are good tomatoes for saucing. Varieties include: San Manzarno, Patio, and Tiny Tim.

Indeterminate Tomatoes can grow anywhere between 1.8–3 m tall. They produce fruit throughout their growing season and finish up in autumn. Although, you may find cherry Tomatoes will continue to produce until it becomes too cold. Popular indeterminate varieties include: Grosse Lisse, Improved Apollo, and Tommy Toe. All indeterminate Tomatoes require stakes or similar for support. You can also use round or triangular Tomato cages for support in both garden beds and containers. Look for them at your local nursery or garden centre.

Tomatoes grow in all climate zones of Australia. In tropical and subtropical climates, they can be grown all year round, but are best in autumn and winter. Growing at other times of the year may result in increased pest and disease control and issues with heat stress. In temperate and cool climates, sow from spring. To get a head start on the season, you can sow seeds indoors in late winter and transplant them into pots or garden beds once the last chance of frost has passed. Wait until seedlings are at least 5 cm tall before transplanting.

Choose a spot in full sun – at least 6-8 hours a day. In areas with particularly hot summers or if a heat wave is expected, it’s a good idea to provide some form of heat protection to help reduce the chance of sunburn and moisture stress. It doesn’t need to be a permanent fixture – a 50% shade cloth secured to star pickets is ideal.

Tomatoes grow best in rich, well-drained soil. Improve the soil with plenty of organic matter, like Yates Dynamic Lifter Soil Improver & Plant Fertiliser.

If growing in pots, choose a pot at least 40 cm wide and deep and fill with Yates Premium Potting Mix with Dynamic Lifter.

Feed Tomatoes regularly throughout the growing season with Yates Thrive Tomato Liquid Plant Food. This potassium-rich fertiliser will help promote healthy leaf growth as well as encourage lots of flowers that will turn into delicious, juicy Tomatoes. Alternatively, you can also use Yates Thrive Flower & Fruit Soluble Fertiliser – this product is widely available and will also help boost plant growth and fruit. 

Water regularly throughout the growing season. Ideally water early in the morning, and only water when the soil starts to dry out slightly.

Add a layer of organic mulch, like sugarcane or pea straw to help retain soil moisture and suppress weeds too.

As indeterminate Tomatoes grow, they produce side shoots or ‘laterals’ that sprout between the joint of the main stem and fruiting branches. Remove these laterals by pinching them off with your thumb and index finger. If these laterals have already developed into thick shoots, use secateurs or a sharp blade to remove.

Pruning these shoots prevents plants from becoming too unruly or congested with stems. It also increases air flow between leaves and stems, reducing the likelihood of diseases like Powdery Mildew.

You can pick off Tomato flowers after planting, but this is only somewhat needed within the first couple of weeks. The idea is to help the plant invest energy in growth rather than wasting energy on fruiting. Once they have settled in, you can stop picking off the flowers.

It's best to give Tomatoes as much space as possible to help with air circulation and to prevent pest activity. However, there are some companion plants that might prove useful such as Marigolds and Basil. Avoid planting near established shrubs as these are likely to out-compete the Tomatoes. 

The benefits of staking Tomatoes are that it improves air circulation to prevent fungal diseases, and it keeps most of the plant away from ground level where pests begin. You are also taking advantage of space and light.

Staking Tomatoes will give you fewer pests and diseases, and provide more space and better growth and fruiting.

When starting your Tomato seeds and very young seedlings off, Tomatoes can be grown inside for a short time. Once they grow up to 10 cm tall, they are best grown outside in full sun.

If you really want to grow Tomatoes indoors, you will need to grow them hydroponically.

Hand-pollinating outdoor grown Tomatoes is not necessary. Bees and other pollinators will pollinate the flowers for you. You can encourage more bee and beneficial insects into the garden by planting more flowering plants, especially blue flowering plants like Salvia and Lavender.

However, if you are growing Tomatoes in a greenhouse, or hydroponically, then you will need to hand-pollinate them. Do this on a warm day, either by just shaking the flower stem gently, or by tickling the centre of a flower with a paintbrush.

Once the season has finished, follow our Post Tomato Plan. Remove plants from pots or garden beds and add to the compost or green waste bin. Prepare for your next crop by refreshing the soil with Yates Dynamic Lifter Soil Improver & Plant Fertiliser.

When you plant next season’s Tomatoes, ensure you choose a garden bed where Tomatoes have not been previously planted. Certain Tomato diseases are carried in the soil, so it’s a good idea to practice crop rotation and plant in a different spot each year. Avoid planting in the same part of the garden for at least four years.

Choose a sunny spot in the garden with well drained soil and enrich with Yates Dynamic Lifter Soil Improver & Plant Fertiliser. Add Yates Hydrangea Pinking Liquid Lime & Dolomite to help sweeten the soil and help prevent Blossom End Rot.

If you have purchased a hybrid Tomato, like Improved Apollo, we do not recommend saving the seed from the ripened fruit. The resulting fruit from that seed aka ‘F1 progeny’ will not be the same Tomato as the one you bought.

However, if you would still like to experiment with saving seed, try it with store-bought Tomatoes or heirloom varieties. Here’s how:

Sap-sucking pests, especially Aphids can cause the new growth of Tomatoes to curl and twist. Other things that might cause similar symptoms are heat or herbicide-spray drift.

Caterpillars, Aphids and Whiteflies find Tomatoes irresistible. To help control them in your garden, spray at first sight with Yates Baythroid Advanced Garden Pest Insect Killer Ready to Use Spray. Spray foliage thoroughly, including the undersides. This product works by contact action, so good coverage of insects is essential.

Tomatoes are sometimes attacked by Mites and can be treated with Yates Lime Sulfur.

Ripening Tomato fruits that fall off the vine prematurely, with pin-prick sized holes in the fruit, and are full of maggots/grubs have been attacked by Fruit Fly.

See How to Stop Fruit Fly Attacking Tomatoes for control methods.

If you live in an area with Fruit Fly you will need to protect your plants against this dreadful pest. Begin applications of Yates Nature’s Way Fruit Fly Control while fruit are still small and before they have changed colour. Otherwise, you will end up with little, cream-coloured ‘worms’ in your fruit. You can try harvesting Tomatoes a bit earlier, when just changing colour, and bring them inside to safely complete ripening. Also try growing cherry-sized Tomatoes instead, as these are much less susceptible to Fruit Fly attack.

Early Blight causes Tomato leaves to become distorted, with dark brown to black spots on the leaves that have a distinct concentric ring pattern (hence the term ‘target’ spot). You will often find the lower leaves are attacked first and in severe cases, the leaves wither, become crispy and eventually die. Brown elongated markings may also be seen on the stalk and are surrounded by a yellow halo. On the fruit, the fungus attacks near the fruit stalk and can cause rotting on one side.

Tomatoes can also succumb to diseases such as Powdery Mildew, Rust, Early Blight or Target Spot and various Leaf Spot diseases. These can all be treated with Yates Tomato & Vegetable Dust and is best applied as a preventative treatment. Dust seedlings approximately 7 days after transplanting and repeat at 7-10-day intervals. Apply uniformly, ensuring that the upper leaf surfaces of foliage are covered.

This condition is known as Blossom End Rot and can be fixed by improving the drainage and using fertilisers that have calcium.

Yates Hydrangea Pinking Liquid Lime & Dolomite will help sweeten the soil and add extra calcium.

Netting is the best thing to prevent birds and Possums from attacking your tomatoes. Use a bird-safe netting and drape then secure over the top of a framework - this will keep the fruit far away from pecking birds and stop the netting from damaging the plant.

See Rats and Mice for control options.

There are a few reasons why a Tomato plant is not fruiting including lack of sun, lack of nutrients, and excess nitrogen and lack of potassium.

Make sure the plant is getting enough sunlight (at least 6 hours direct) and feed with a Tomato and vegetable fertiliser such as Yates Thrive Natural Vegie & Herb Organic Based Pelletised Food. Avoid using all-purpose fertilisers as these tend to be high in nitrogen.