Cup Day is the traditional date for Melburnians to plant their backyard tomatoes for a tasty summer crop. But if you haven’t grown them before, where do you start?

We asked local gardening enthusiast Peter Barber for his tomato-growing advice. He volunteers with Kew Neighbourhood Learning Centre’s horticulture program and gardens at Willsmere Station Community Garden in Kew.  

Peter started gardening 15 years ago when looking for a new focus after being retrenched. ‘I started in the backyard at home and after the first summer I was hooked on growing veggies,’ he says.

Being in the garden boosted his health and wellbeing. Joining the Willsmere Station Community Garden – 5 years old this year – added community connection to the mix. ‘And the produce is so fresh and full of flavour.’

Peter says tomatoes are a popular choice at the community garden. ‘Tomatoes are everyone’s favourite plant at this time of year. There’s nothing like the flavour of a home-grown, sun-ripened tomato.’ 

Read Peter’s tips below to help you grow your own bumper summer crop.

How to grow backyard tomatoes

Is Cup Day really the best time to plant tomatoes in Melbourne?

Cup Day is a good indicator that we’re moving towards warmer weather. The soil should be warming up and air temperatures remaining constant. I wait until day temperatures are steady in the mid-20 degrees Celsius and night temperatures are around 15 degrees. This means tomato plants have ideal conditions as soon as they’re planted out.

What are the biggest mistakes gardeners make when growing tomatoes?

Overcrowding and overwatering.

Where should gardeners grow their tomatoes?

The best place is in an open, sunny spot where they’ll get 8 hours of sunlight a day. Plants should be spaced to allow each one to grow without crowding or reducing airflow. Check the label on nursery plants for the recommended spacing as it will vary depending on the variety’s growth habit and size.

Do they need to prepare the soil before planting?

Tomatoes are heavy feeders and need nutrient-rich soil. Add compost to increase organic matter and dig it in well. This improves the soil structure and helps retain nutrients. Tomatoes like slightly acidic soil. A pH of around 6.0 to 7.0 is ideal. 

How often should they water?

The soil around your tomatoes shouldn’t be left to go dry. Keep it moist. A weekly water to the base of the plant should be enough and will promote deep root growth. Check visually that soil is moist or use a water meter. Also take care not to overwater – tomatoes don’t like soggy soil. Mulching around your plants will help the soil retain water and will suppress weeds.

What about feeding?

Apply a seaweed-based liquid treatment when you plant your tomatoes and 2 weeks later to promote root growth. Apply a liquid fertiliser formulated for fruit growth only when the plant begins to flower. This sets it up to produce lots of flavoursome fruit.

What else can gardeners do to boost fruit?  

You should remove any lateral or side leaves that grow where the leaves join the main stem. This reduces leafy growth and concentrates the plant’s growing energy in the flowers and fruit.

Are companion plants helpful? 

Yes they are. Basil is a popular companion plant for tomatoes. So are radishes, beans, marigolds, sunflowers and thyme.

Are there any pests or diseases to look out for? 

Aphids can be a problem. Control these tiny green mites by squashing them or spraying with soapy water. Powdery mildew is a disease that commonly affects tomatoes. Look for whitish-grey powdery spots on the leaves. To treat it remove the affected leaves, prune the plant to help the air circulate better, and water the base of the plant – not the leaves.

Are any particular varieties easy to grow for beginners? 

There’s such a wide range of tomato varieties – so try what you like. Smaller cherry-type tomatoes can be a good place to start. They mature quickly and will produce throughout the season.

Can I grow tomatoes in pots?

Yes you can. Most can be grown in pots. Keep in mind the hours of sunshine needed to grow the best fruit.

Do you have any tips for amateur gardeners?

The best advice I can give is to read widely and talk to other gardeners. There are plenty of great gardening books, shows like Gardening Australia have lots of information and the internet is a valuable source. And try to experiment and learn from growing.