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Tomatoes are tenderperennial plants which are treated as annuals and cropped in one season after which the plants are discarded or killed off by frost. A great range of tomato fruit types are now available from seed suppliers with fruits ranging from Cherry and Plum to over-sized Beefsteak cultivars. They come in many shapes from traditional round, to oblong or elongated and the colour range includes red, yellow and orange or striped.

Seed catalogues list many varieties from the traditional Heirloom cultivars to the modern F1 hybrid cultivars. F1 hybrids tend to be heavier croppers and have stronger disease resistance. Grown from seed in a propagator, or from plants purchased in the garden centre, different types of tomato suit different methods of use.

Types of plant

  • Tomato plants are grown as either: vine (indeterminate) plants or bush (determinate)
  • It is important to know which type you have as the method of supporting the plants is different.

Vine plants

  • Are produced on a single stem with all sideshoots removed and supported by twisting the new growth clockwise around a string (tied at the base of the plant and secured on a strong overhead wire). This keeps the fruit clean and the plant off the ground where it would otherwise lie on the soil surface.
  • Fruits develop on trusses that grow at intervals on the main Vine plants are more suited to indoor production.

Bush plants

  • Are not trained and all shoots are allowed to grow.
  • Flowers appear at the end of each stem and develop into fruits.
  • They are generally shorter season plants and are often used outdoors in the ground or in containers or baskets where they are allowed to trail over the edge. 

Where to grow

  • In the Irish climate, tomatoes will generally require some form of protection, such as a greenhouse or polythene tunnel or cloche to produce successful crops.
  • If cropping outside consider planting bush types in containers or hanging baskets in a bright sheltered If planting directly into the soil it may be best to plant through black plastic mulch.


  • To avoid a build-up of soil borne disease, fresh soil is recommended for each new
  • Any fertile, well-drained soil is suitable, if plenty of organic matter has been incorporated in the top
  • If necessary, before planting add a general-purpose fertilizer at a rate of 100g per m2, or pelleted poultry manure at 150g per m2.
  • Consider using a cloche to protect small plants early in the
  • Try not to plant your tomatoes in the same area as potatoes as they are from the same family and are prone to similar


Border soil

  • If growing in the border soil, old soil will need to be replaced at the beginning of each new crop to avoid build- up of soil borne
  • Tomatoes grow best in high organic matter soils, so digging some good compost into the soil beforehand would be beneficial.
  • The pH of your soil should be in the range from 5-7 for best growth. At a pH below 5.5, plant growth will be affected.


  • Growing in good quality compost or in specially produced growbags will cut out the chore of moving soil. The pH of the growing medium will already be adjusted so no extra lime will be needed.
  • Three plants per standard growbag would be suitable.
  • The compost in the growbags will contain enough nutrients to carry the crop for 2-3 weeks after planting.

Sowing seeds and growing on seedlings

  • Don’t be tempted to sow seeds too early in the year. Poor light will lead to weak seedlings and spindly growth and your plants may be ready to plant before weather conditions are suitable.
  • Sow mid-March to early April to plant out mid to late May.
  • Loosely fill a 10cm pot with fine ‘seed and potting’ compost. Slightly firm the compost to 1 cm below lip of the pot. Water up carefully with clean water using a fine rose on the watering can. Sprinkle about 10 seeds per pot onto the moist compost surface.
  • Cover lightly with a layer of fine compost and water in with a fine rose to avoid disturbing the seeds. Warm conditions (15-25oC) are needed for germination.
  • Use a heated propagator for best results. The enclosed atmosphere will maintain a high humidity during germination.
  • When seedlings emerge, transfer to a bright greenhouse or sunny windowsill. After germination, seedlings should be grown on at 21-24oC.
  • When the seedlings are large enough to handle, prick out into individual 10cm pots. When handling the seedling, hold plant by the seed leaf, not by the stem. This avoids damage to the stem which could result in loss of the plant.
  • Feed with a balanced liquid fertiliser (according to manufacturer’s directions) after 2-3 weeks, or if leaves appear pale or discoloured.

Purchasing Plants

  • Where a small number of plants from a range of varieties are required, purchasing plants from the garden centre or garden shop is an option.
  • Select healthy plants that are not wilting and are free of Check around the plant and the underside of the leaves for signs of pests.
  • Choose varieties and the number of plants required for the space available in the garden or greenhouse.


  • Plant out, into growbags or soil, after roots have filled the pot, the first flower buds appear and any frost is finished.
  • Remove the pot and plant deep enough to support the plant allowing the soil or compost to cover a few inches of the stem above original compost level.
  • For bush plants in containers or baskets, use a good quality potting compost, plant up indoors and grow on there for a couple of weeks before placing outdoors in a sheltered spot near a south-facing wall. Allow the plants to harden off by placing them outside during the day and protecting them indoors on cold nights. Place outside when plants have toughened up.
  • Tumbling cherry varieties perform well and give lots of small sweet fruit if regular feeding with a high potash tomato feed takes place (according to manufacturer’s instructions). Large pots in a sheltered spot planted up with dwarf bush types and some pots of fresh sweet basil are a great combination.

Growing-on and Training plants


  • Cover bush tomatoes with fleece or cloches, to protect from cold early in the season and support if needed.


  • Train vine tomatoes, throughout the growing season twisting new growth clockwise around support string (or strong bamboo cane) removing sideshoots which develop in the axils between the leaves and the main stem. 
  • Rub out the sideshoots with your thumb while they are still small, 2-3 cm long. If you try to take them out too soon you may damage the plant. If they are allowed to grow too big they take energy from the main plant and will be difficult to remove.
  • Be careful not to rub out the growing tip as it needs to continue to grow to produce the main stem.
  • Flower/fruit trusses appear on the main stem but not in the leaf axils.

  • No more than 6-8 trusses can be relied upon to ripen in a cold greenhouse season before autumn frosts, so when enough trusses have set fruit, pinch out the terminal shoot, leaving two leaves above the final truss. This allows the fruits present at this stage to develop well and get a chance to ripen. It will usually be too cold for the flowers on later trusses to develop into reasonable sized fruit.


  • Ventilate the greenhouse well during the day in warm weather to cool the crop.
  • Good ventilation is also important to assist in reducing the humidity inside, which can create conditions suited to diseases like botrytis. 
  • If you decide to remove old leaves it is advisable to do this early in the day so the wound has time to heal and dry before nightfall. This will help reduce the risk of botrytis infection.
  • Ventilation also allows beneficial insects to access the plants which will assist in pollination of the fruit.

Watering and feeding

  • Water all types well earlier in the day, especially container plants. Apply water/feed to the root zone soil or compost. Avoid wetting the foliage as this will encourage disease on leaves and fruit. Avoid heavy watering late in the day as it increases humidity and will encourage disease
  • Base nutrients in the soil or compost will keep the plants going for only 3-4 weeks. To maintain nutrient levels include a high potash liquid fertiliser when watering (mix according to manufacturer’s directions). Tomatoes benefit from high levels of potash. It encourages fruit formation and enhances flavour and colour. 
  • Irregular watering can lead to blossom end rot and cracking of the ripening fruit.
  • Under watering can mean that salts are not flushed out and the salinity of the growing media increases, reducing the availability of some nutrients.
  • Over watering results in the leaching of nutrients and poor aeration.


  • Leaving fruits to ripen on the vine, will allow them to develop full colour and flavour. Pick as required. Excess fruit can be made into chutney.
  • At the end of the season, pick remaining green fruits and leave them in a warm place to ripen or use extra green fruit to make chutney.