Tomatoes: How to Grow, Feed & Harvest for the Best Results

Homegrown tomatoes deliver unbeatable flavour, nutrition, and satisfaction—especially when grown with the right fertiliser strategy. This guide walks you through every step, from planting time to feeding and harvest, using premium products from Complete Grow.

When to Plant Tomatoes in Australia

Tomatoes can be grown across Australia, but the timing varies:

Cool & temperate zones: Sow seeds from late winter, transplant in October–November after frost risk ends.
Warm temperate zones: Start planting from August and continue into early summer for a longer season.
Tropical & subtropical: Grow year-round, ideally during cooler months for better yield and pest control.

Sunlight, Containers & Spacing

Tomatoes require full sun (6+ hours daily). Avoid planting in the same soil as last year to prevent disease. In smaller spaces, use large pots (30cm+) with drainage holes and choose compact or cherry varieties that do well in containers.

Spacing for garden beds: 50–60cm between plants in rows 60cm apart.
Support: Stake or cage plants early to encourage upright growth and avoid stem breakage.

Growing from Seed

Start seeds in punnets or 10cm pots using seed-raising mix. Keep warm and moist. Tomato seeds germinate in 6–14 days at temperatures above 16°C. Once the second set of leaves appear (true leaves), thin them out and begin light feeding. For early growth, feed with a diluted dose of Complete Grow NPK 20-20-20 every 1–2 weeks to support strong root and leaf development.

Transplanting Seedlings

Once seedlings are 10–15cm tall and have 2–3 sets of true leaves, transplant them into the garden or pots. Bury part of the stem to encourage deeper root growth. Space plants properly and water in deeply.

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Feeding Schedule for Healthy, Productive Plants

Tomatoes are heavy feeders. Regular fertilising throughout the growing cycle leads to stronger plants, better flowering, and more flavourful fruit.

NPK 20-20-20 – Begin using at seedling stage and continue through vegetative growth. Feed every 1–2 weeks.
Advanced NPK 4-18-38 + Cal-Mag – Switch when flowering starts to boost fruit set, size, and flavour while preventing calcium-related issues like blossom end rot.

Adjust application strength depending on plant size and growth stage. Always water fertiliser in well.

Watering, Pruning & Mulching Tips

Water deeply 2–3 times a week, avoiding overhead watering to prevent fungal issues.
Prune side shoots and lower leaves to promote airflow and fruit production.
Apply mulch around the base to retain moisture and suppress weeds.

Troubleshooting Common Tomato Issues

Blossom end rot: Caused by inconsistent watering or calcium deficiency. Prevent it with our 4-18-38 + Cal-Mag. Fruit fly: Protect fruit with mesh bags or harvest early and ripen indoors. Target spot: Look for brown spots and leaf yellowing. Prune lower leaves and rotate crops each year.

Harvesting Tips

Tomatoes usually mature 12–20 weeks after sowing. For best flavour, allow them to fully ripen on the vine. In hot climates, pick slightly early to ripen indoors and avoid pest damage. Continue feeding and pruning until the plant slows down with cooler weather.

The Complete Grow Approach to Tomato Success

With just two reliable, high-performance formulas, you can take your tomatoes from seedling to harvest:

NPK 20-20-20 – Balanced, highly soluble and ideal for growth and early development.
NPK 4-18-38 + Cal-Mag – Designed for flowering, fruiting, and overall plant health.

Choosing the Best Fertilizer for Tomato Plants

Not all tomato fertilisers are created equal. The best fertilizer for tomato plants provides balanced nutrition during every phase—from early leaf growth to fruit ripening. Whether you’re growing in garden beds, raised planters or containers, Complete Grow makes it simple.

For leafy growth and early stages: Use NPK 20-20-20 for fast-absorbing, balanced nutrition that supports strong roots and lush leaves.
For flowering and fruiting: Switch to NPK 4-18-38 + Cal-Mag to fuel healthy blooms, big tomatoes, and protect against blossom end rot.

Whether you’re a backyard gardener or a balcony grower, choosing a proven, high-quality tomato fertiliser is the key to consistent harvests and rich flavour.