Tomato Orange Accordion

How to Sow and Grow Tomatoes

Tomatoes are one of the most rewarding plants to grow in your garden. Not only are they delicious and versatile in the kitchen, but they also come in a variety of shapes, sizes, and colours, adding beauty to your garden. Whether you’re a novice gardener or an experienced green thumb, this guide will walk you through the steps to successfully sow and grow tomatoes.

Tomato Black Strawberry

 Tomato Black Strawberry

Sowing Tomato Seeds

When to Sow: Start seeds indoors 6-8 weeks before the last expected frost date in your area. Some people like an early start on tomatoes and this can sometimes result in an earlier fruit harvest, but remember that tomatoes are very fast growing plants. When deciding how early to start your tomato, consider if you have sufficient room to grow on the plant all the way until after last frosts.

Materials Needed:

  • Seed trays or small pots
  • Peat free multipurpose compost with a fine texture
  • Tomato seeds
  • Grow lights and heat mat when starting before March or for winter growing 
  • A sunny windowsill March start onwards


  • Fill the Seed Trays: Fill your trays or pots with compost
  • Plant the Seeds: Place 1-2 seeds per cell, about 5mm deep. Lightly cover with soil.
  • Water and Cover: Water gently and make sure to maintain those moist conditions throughout the germination process. 
  • Provide Light: Place the trays under grow lights or in a sunny window. Tomatoes seeds need warmth and light to germinate so if starting early a heat mat may also help aid germination.

Germination: Seeds should sprout in 5-10 days. Remove the heat mat once the seedlings emerge.

Cover Tomato Green Copia

 Tomato Green Copia


When to Feed Tomato Plants: Tomatoes are relatively hungry plants and therefore benefit from feeding from an early age. Use a plant based liquid feed such as a seaweed liquid feed.


  • Seedling stage: Begin feeding when plants are around 15ch tall using a very diluted solution of feed. Aim to use a roughly quarter strength solution as per manufacturer’s guidelines on the packet.

  • Once Planted Out: If tomatoes are planted into a well mulched nutrient dense soil, they will not necessarily require any feeding, however if unsure, regular feeding can remove the risk of nutrient deficiencies that tomatoes can be prone to. Mix liquid feed as per manufacturer’s guidelines and use every 2 weeks though growing season. Water into the soil at the base of the plant, not onto foliage.

Transplanting Seedlings

When to Transplant: Tomatoes cannot survive any frost and temperatures below 5c will cause them to stall in growth. Always wait until all risk of frost has passed before planting out.


  • Harden Off: Gradually acclimate seedlings to outdoor conditions by placing them outside for a few hours each day, increasing the time over a week. Alternatively transfer to an unheated greenhouse to grow on, being careful to protect from frosts if necessary.
  • Prepare the Garden Bed: Choose a sunny location with well-draining soil. Top dress the soil with compost.
  • Planting: Dig a hole deep enough to bury the seedling up to its first set of true leaves. Tomatoes can grow new roots out of their stems so burning them deeply encourages a stronger root system.
  • Water: Water thoroughly after planting.

Caring for Tomato Plants

  • Watering: Keep the soil consistently moist but not waterlogged. A little water each day is better than a lot of water occasionally as this can cause fruit to split. Watering a little also encourages the plant to send their roots deep into the soil. Water at the base of the plant to avoid wetting the leaves, which can lead to disease. Avoid watering in the heat of the day, aim to water early morning or evening.
  • Mulching: Apply mulch around the base to retain moisture and control weeds.
  • Staking and Support: Provide support for your plants. Use stakes, cages, or trellises to keep the plants upright and the fruit off the ground. Heavy fruit trusses may benefit from extra support so they don’t snap. They can be tied to the main plant support as fruit swells.
  • Pruning: Prune indeterminate varieties to encourage airflow and prevent disease. Remove side shoots (small shoots that grow between the main stem and branches). For more information on pruning read our detailed guide HERE.
Micro Tomato Vilma in pot indoors

 Dwarf Tomato Vilma


Tomatoes are ready to harvest when they are fully coloured and slightly soft to the touch. Pick them regularly to encourage more fruit production. If frost threatens, green tomatoes can be harvested and ripened indoors. There are many ways to preserve your excess tomato harvests but the simplest way is simply to freeze whole. Frozen tomatoes can then be used in cooking and sauces over winter.

Common Problems and Solutions

Blossom End Rot: Caused by calcium deficiency and inconsistent watering. Ensure regular watering and consider some additional liquid feeds until the problem resolves. We find longer shaped tomatoes are more susceptible.

Pests: Watch for aphids, whiteflies. You can handpick pests off plants. Mice, rats and pigeons are also partial to ripe tomatoes.

Diseases: Fungal diseases like blight can be minimised with proper spacing, pruning, and avoiding overhead watering. Blight is also much less likely when growing indoors such as a greenhouse or polytunnel. Should blight appear on your plant, don’t panic! Diligently prune all effected areas to keep the plant going as long as possible.

Growing tomatoes can be a fulfilling and delicious endeavour. By choosing the right variety, starting seeds indoors, carefully transplanting seedlings, and providing proper care, you’ll enjoy a bountiful harvest. With patience and attention, you’ll soon be savouring homegrown tomatoes in your favourite dishes. Happy gardening!

Shop Heirloom Tomato Seeds

Video – How to Sow and Grow Tomatoes