Solving Tomato Problems

Feed Tomatoes every 1-2 weeks throughout the growing season with a potassium-rich fertiliser like Yates Thrive Flower & Fruit Soluble Fertiliser or Yates 500mL Thrive Tomato Liquid Plant Food. These balanced fertilisers help promote healthy leaf growth as well as encourage lots of flowers that will turn into delicious, juicy Tomatoes. 

Tomato plants develop side shoots, called laterals, between the main and horizontal stems. Removing the laterals from indeterminate tomatoes (varieties that are tall growers and fruit continuously over several months) helps to promote healthier plants and more fruit. These lateral shoots can be pinched out as soon as they’re noticed.

Tomato fruit can be susceptible to sunburn. In areas with hot summers or if a heat wave is expected, it’s a good idea to provide some form of sun protection to help reduce the chance of sunburn and moisture stress. It doesn’t need to be a permanent fixture – a section of 50% shade cloth secured to star pickets or erecting a beach umbrella during hot weather is ideal. 

Tomatoes are susceptible to several common pests. Caterpillars (sometimes known as Tomato fruitworm), Aphids and Whiteflies all find Tomatoes as delicious as we do! These pests can damage either foliage or fruit or both. As soon as pests or their damage are noticed, spray 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 can also be attacked by Fruit Fly. Affected fruit has small white grubs inside and fruit can rot. If you’re in a Fruit Fly prone area, you will need to protect your plants. Begin applications of Yates Nature’s Way Fruit Fly Control while fruit are still small and before they have changed colour. In addition, you can also try harvesting Tomatoes a bit earlier, when they’re just changing colour, and bring them inside to complete ripening. Growing smaller cherry Tomatoes is also worth considering, as they are reported to be less susceptible to Fruit Fly attack. 

Particularly during humid or rainy weather, there is a range of common Tomato plant diseases to monitor for, including fungal diseases like Blight and Powdery Mildew. Infected plants can show symptoms on both leaves and fruit. Early Blight causes Tomato leaves to become distorted and develop dark brown to black spots with concentric circles. You will often find the lower leaves are infected 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. 

Powdery Mildew disease appears as white or grey powdery patches on leaves, which can lead to yellow spots and leaves to drop. 

Blight and Powdery Mildew, as well as other diseases like Leaf Spot, Downy Mildew and Rust, can all be treated with Yates Tomato & Vegetable Dust.  Dust seedlings approximately 7 days after transplanting and repeat at 7-10-day intervals. Apply uniformly, ensuring that both the upper and undersides of leaves are covered. During wet weather, more frequent applications may be required. It can also help to remove any yellow infected leaves or leaves with brown spots from the plant, which reduces disease spread.  

Some viruses that affect Tomatoes are spread by small sap-sucking insects such as Aphids and Thrips. Watch out for these pests, as even though they’re small they can lead to serious virus infections. Yates Tomato Dust will control Aphids and Melon Thrips. Insecticidal soap, such as Yates Nature’s Way Vegie & Herb Spray, can also be used to control sap-sucking insects like Aphids and Thrips.   

Tomato flowers need to be pollinated to form fruit. Flowers are pollinated by wind or special insects like the Australian native blue-banded bee. Planting lots of flowers in your garden that attract beneficial pollinating insects can help improve Tomato fruit set, as can growing plants in an airy position. You can even try hand-pollination (with a small paintbrush) or gently shaking the plants to help move pollen around between flowers.  

Cold temperatures can cause blossom drop (therefore affecting fruit set), however once the weather warms up, more flowers will develop and hopefully fruit will follow. In addition, cold weather can lead to a problem called ‘cat-facing’, where fruit develops abnormally and appears dimpled and scarred. Improved weather conditions will result in less cat-facing.   

Prolonged very hot weather can also lead to blossom drop. Try creating a shade structure to help protect your Tomato plants from harsh sun.  

Well-fed and watered plants will produce more fruit, so regular watering and feeding is important.  

For more information, visit our comprehensive guide on How to Grow Tomatoes in a vegie patch or pots.