🍅 How to Grow Tomatoes from Seed
The tomato is the most popular vegetable going — even people who consider themselves non-gardeners will somehow manage to make room for a plant or two. Tomatoes thrive on three things: warmth, lots of sunlight, and an even, steady supply of water.
- Sow Indoors 6 to 8 weeks before final spring frost
- Germination Temperature 21°C to 24°C
- Days to Harvest 60 to 80 days from transplanting (varies by cultivar)
- Determinate Spacing 60 cm apart
- Indeterminate Spacing 90 cm apart
- Sun Requirement Full Sun ☀️
🧭 Step-by-Step Culture Guide
1. 🌱 Sowing Indoors
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Timing: Sow seeds indoors 6 to 8 weeks before your final spring frost date.
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Media: Use a clean, soilless growing mix to significantly lessen the chance of fungal seedling diseases.
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Temperature: Keep the seeding mix warm at 21°C to 24°C to ensure prompt, uniform germination.
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Caution: Avoid planting too early! Cold, wet soil can permanently stunt developing root hairs.
2. 🪴 Potting Up
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Timing: When seedlings reach roughly 4 cm high, they are ready for more space.
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Handling: Carefully transplant them into their own individual small pots or cell packs.
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Environment: Grow them under bright, direct light at a cooler, sturdy room temperature of 16°C to 21°C until outdoor planting time.
3. 🏡 Transplanting Outdoors
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Hardening Off: In mid to late May, gradually acclimatize your indoor seedlings to outdoor wind and sun over a 7 to 10-day period.
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Soil & Timing: Once nighttime temperatures are consistently above 13°C, transplant them into loose, well-drained organic garden soil.
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Spacing:
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Bush (Determinate) varieties: Space 60 cm apart.
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Vining (Indeterminate) varieties: Space 90 cm apart.
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4. 💦 Crop Maintenance
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Watering: Apply water directly to the soil using drip irrigation or a watering can. Avoid showering down over the foliage, as wet leaves easily invite fungal pathogens. Keep soil consistently moist to prevent wilting at any growth stage, as fluctuations in moisture cause blossom-end rot in maturing fruit.
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Mulching: Apply a thick layer of straw or shredded leaves around the base. This stops soil-borne spores from splashing onto lower leaves and conserves critical soil moisture.
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Feeding: Use a granular or water-soluble fertilizer high in phosphorus and potash. Avoid excessive nitrogen, which causes lush, dark green leaf growth at the expense of flower and fruit production.
🛠️ Troubleshooting Common Tomato Problems
🩺 Environmental & Physiological Issues
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⚫ Blossom-End Rot (BER): A sunken, leathery, black patch develops on the bottom of the fruit. This is a calcium delivery issue within the plant, almost always triggered by inconsistent soil moisture or root damage from cold soil. The Fix: Maintain an even, steady watering routine and mulch your plants to stabilize soil moisture.
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🛑 Blossom Drop & Poor Fruit Set: Flower stems turn yellow, and blossoms dry up and drop off without setting fruit. This happens when daytime temperatures exceed 32°C or nights stay above 22°C, causing pollen to become sterile. The Fix: Use a 30% garden shade cloth during prolonged summer heatwaves and avoid high-nitrogen fertilizers.
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⚡ Cracked Fruit: Concentric circles or radial splits tear open near the stem end. This is caused by rapid fruit expansion following heavy rain or uneven watering. The Fix: Water consistently. Reduce watering slightly as fruit nears ripeness, and pick nearly-ripe clusters early if heavy rainfall is forecasted.
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☀️ Sunscald: White, papery, blistered patches form on green fruit exposed to intense, direct sunlight. The Fix: Avoid over-pruning the leaf canopy and manage foliar diseases so that natural leaf cover protects the ripening fruit clusters.
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🐱 Cat-Facing: Misshapen, puckered, or deeply scarred fruit with brown creases at the blossom end. This is caused by cool daytime temperatures (15°C to 18°C) during early flower bud development. The Fix: Delay outdoor planting until the spring weather is reliably warm.
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🔄 Physiological Leaf Roll: Lower leaves cup upward and roll inward lengthwise, becoming thick and leathery while remaining green. The Fix: Don’t panic! This is a harmless stress response to excessive moisture, severe pruning, or minor transplant shock. It will not hurt your harvest yield.
🐛 Pathogens & Pests
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🍂 Foliar Blights & Wilts (Early Blight, Septoria, Fusarium): Lower leaves develop yellowing, dark target-like spots, or sudden wilting that moves upward through the plant. The Fix: Avoid planting tomatoes or other members of the Solanaceae family in the same location every year. Rotate your crops annually, mulch to stop soil splashing, and clip off infected lower leaves immediately. Destroy heavily infected plants; never compost them.
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🟤 Anthracnose (Dark Fruit Spots): Ripe fruit develops dark, circular, sunken spots. These fungal spores overwinter in garden debris and splash upward. The Fix: Stake or trellis your plants off the ground, apply mulch, pick fruit promptly, and follow a strict 3-year crop rotation away from all solanaceous crops (tomatoes, peppers, and eggplants). Do not save seeds from infected plants.
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🦠 Viral Infections (Mosaic Virus, Yellow Leaf Curl): Leaves become severely mottled, stunted, or tightly cupped, sometimes accompanied by purple veins or internal fruit browning. The Fix: Viruses are incurable. Immediately pull and destroy infected plants. Control nearby weeds (which host pest vectors like whiteflies) and thoroughly sanitize your garden tools and cages.
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🐛 Nibbled Fruit: Pests like hornworms, groups of slugs, birds, or small mammals bite into or damage the fruit. The Fix: Check your plants daily to hand-pick large hornworms, encourage predatory beneficial insects (like parasitic wasps), or install protective fencing and netting where necessary.