Top Tips: Growing Tomatoes

Want to grow your best tomatoes ever? The largest tomato on record – a whopping seven pounds, 12 ounces – was picked in Edmond, Oklahoma, in 1986. The Guinness World Record for the tallest tomato plant is 19.8 meters – that's 65 feet – grown hydroponically by a little company in Lancashire....that's us by the way!

Follow our advice to growing your best tomatoes ever – perhaps you'll have a record breaker! 

How to Grow Tomatoes - Tomato Growing Guide

Growing Tomatoes - Top Tips

When growing your own tomatoes, choose a variety that will be suited to the space you have available and the flavours and textures you like. Tomato varieties grow as vines (cordon) or bushes. If you are thinking of what to grow in a greenhouse, tomatoes are a great option.

1: Vine tomatoes, also known as indeterminate or cordon, are the most popular tomato to grow and are best if you are growing tomatoes in greenhouses and polytunnels. These tomato plants can grow to several metres long.

2: Bush tomato varieties, also known as determinate tomatoes, are more compact, ideal for outdoor tomato growing.


Did you know?

Plants that receive the perfect balance of water and nutrients are healthier and stronger, helping them to have a greater resistance to pests and diseases.

Most problems occur when plants receive too much or too little water... knowing how much to provide usually involves a little guesswork and green fingers!

If you would like to grow tomatoes more successfully our Quadgrow Self-watering planter may be just what you are looking for. It's ideal for your tomatoes.

Thanks to the clever FeederMat powered watering which pulls water up from the SmartReservoir to the roots just when the plant needs it, we guarantee they'll produce bumper harvests!

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Harvests are 2x bigger when grown in a Quadgrow planter compared with grow bags or pots because it automatically waters your plants for 14 days at a time. Even better, it does it all without electricity or timers!

Each Quadgrow holds 4x plants and includes everything you need.

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quadgrow self-watering planter


Tomato Growing Varieties

Vine tomato types are grown with a single main stem and the side shoots need to be removed regularly. These tomato plants can grow to be several meters long and therefore they need to be supported. 

When growing vine tomato varieties, ensure you provide them with sufficient plant supports such as support frames, canes or plant support ties.

Bush types are more compact tending to stay bushy and quite short and are very easy to support with a bamboo cane. Popular varieties include Tumbling Tom, Red Alert and Garden Pearl. It is not necessary to remove the side shoots with these varieties.


Growing Tomato Plants from Seed -  When to Plant?

If you are wondering when to plant tomatoes, the seeds are best sown at the following times;

  • In a heated propagator like our Vitopod Heated Electric Propagator or heated greenhouse - sow January to early February.
  • In an unheated propagator or unheated greenhouse - sow late February to early March.
  • When planting tomato seeds outdoors - sow late March to early April.


1) Sow the tomato seeds

  • Fill a seed tray with compost (any multi-purpose compost) and flatten the compost down lightly using a tamper.
  • Place seeds on the surface of the compost, space the seeds evenly and sow a few more than you need. Cover the seeds with approx. 0.5 to 1cm of compost.
  • Water the compost so that it is damp but not saturated.
  • If you have a propagator put the seed tray in the propagator and put the lid on.
  • If growing tomatoes in pots from seeds or in a propagator, place it in a warm place away from direct sunlight. The room needs to be a minimum of 18°C.


2) Care for tomato seedlings

  • Day 17-28: Seedlings should appear but some varieties can take up to 28 days to germinate – see your seed packet for details.
  • Once the seedlings have appeared move the propagator/seed trays to a bright, warm part of the house, a windowsill is ideal. Keep the compost moist, but not wet. If you are using a propagator lid remove the lid when all seedlings have appeared.


3) Transfer to tomato plant pots

  • Day 50-60: Seedlings of most varieties will be large enough to be moved into individual 3 inch pots
  • Fill a 3 inch pot with compost and use a pencil to make a hole large enough for the seedling.
  • Hold the tomato seedling by its leaves and gently lever up and out of the seed tray with a dibber or pencil and lower the seedling into the potting mix its new pot.
  • Gently firm the compost around the plant ensuring the roots are covered and adding compost to fill the pot.
  • Water the compost so it is damp but not saturated.
  • Place the pots in a warm and sunny spot such as a heated greenhouse, conservatory or windowsill in a warm room.


4) Transfer to the final large pot

    • Once the tomato plants are 6 to 8 inches tall plant them into your Quadgrow Planter or other chosen tomato planters between 6 and 12 inches in diameter (see seed instructions for ideal large pot size). If using a Quadgrow follow the assembly instructions.
    • If you are using a heated electric propagator, you will need to gradually wean the tomato plants off the heat of the propagator. The timing of this stage depends on the temperature conditions and whether you have a heater in your greenhouse or polytunnel. This process is called 'hardening off'.


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Hardening off Tomatoes

Young tomato plants need to be gradually weaned off the heat of a propagator, greenhouse or polytunnel. The timing of this stage depends on the temperature conditions and whether you have a heater in your greenhouse or polytunnel.



The weaning off period required depends on the time of sowing rather than the development stage of the plant. This is because the key is not to subject your young plants to night temperatures below 4°C without protection.

Once your plants have developed their true leaves (the leaves that are typical of the mature plant, not the two leaves that first appear) they will usually be ready to be weaned off the heat for a few days.

Gradually decrease the humidity by turning the heat down and gradually off, opening the vents and then removing the lids.

Once the plants have been in the propagator without a lid and no heat for a couple of days you can remove your plants, just keep an eye on the night temperatures.


Night Protection in an unheated polytunnel or greenhouse

If you are growing tomato plants in an unheated polytunnel or greenhouse you will need to provide protection at night until the night-time temperature in your greenhouse/polytunnel is no cooler than about 10°C.

When temperatures are between 5° and 10°C keep your plants in the heated propagator OR place a mini greenhouse or a cloche over your plants to give your plants extra protection on cold nights.


Tomato Plant Care

Tomato plants can be placed outside once all risk of frost has passed, but they will do better if kept in a greenhouse or indoors overnight until the summer when daytime temperatures are no lower than 17C.

If you are using the Quadgrow keep the SmartReservoir topped-up as per the Quadgrow instructions.

If you are growing tomatoes in pots outside take care not to let the plant dry out too much or to over-water. Tomatoes hate irregular watering - overwatering or sporadic watering can cause blossom end rot or cause the fruit to split - little and often is the rule here. Try to avoid watering in the evening. Tomatoes will use very little water during the night. It is always better to water in the mornings and early afternoon.

Unless you are growing in one of our planters and using our water soluble plant nutrients, feed them with a organic tomato fertilizer or liquid fertilizer until they are established. Following that use a high potash fertiliser for your tomatoes to encourage them to flower and fruit.

Another tomato plant care tip is to keep them weed-free and keep an eye out for the common pests.


Side-shooting tomatoes

Vine varieties need their side-shoots removing - this involves removing the new shoots that grow between the leaf and the stem. This ensures your tomato plant puts all its energy into growing its main stem until you remove the growing tip. Take care to remove the side shoots cleanly, without leaving any stubs or damage as this will encourage fungal diseases such as botrytis.

You can use these side shoots to grow more plants. Tomatoes are easy to grow in our Hydropod cuttings propagator

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Tying-in - Tomatoes up String

It is easier to manage vine varieties if you grow the tomatoes up string. To perform this string method of growing you tie the plant up with string and twist the growing point around the string to promote plant growth.


Pinching-out the growing tip

Usually the growing tip is pinched out when the plant reaches the desired height. Don't leave it too late in the year before removing the growing tip as there may not be enough time to ripen off the last fruit (unless you enjoy making chutney). Leave 2 leaves above the top flowering truss when removing the growing tip. This will ensure the last tomatoes grow to full size.


Removing Leaves

Taller plants will require some removal of the lower leaves, known as deleafing, to encourage ripening of fruit. Use a sharp knife to deleaf flush with the stem. Remove leaves up to the first low growing tomato plants that have ripening tomatoes on.


Harvesting Tomatoes

Harvest can begin from mid-May and continue through to October depending on where your tomatoes are grown (when using our Vivigrow planters in a greenhouse you could even still be picking in December).


Frost and green tomatoes

See our guides to ripening green tomatoes and protecting plants from frost.

When night temperatures are below 4°C bring your young plants into the house overnight.

We find that putting the pots on a tray makes it easy to bring all the plants into the house without too much trouble. 
*Do not put tomatoes outdoors until the night temperatures do not drop below 10°C. We’re in Lancashire, so for us that means late April, which would mean sowing in March.


We grew 5 varieties, Scarlotto, San Marzano, Rosada, Sweet Million and Beefsteak tomatoes in our Quadgrow Self-watering Pots and our Gardening Angels closely followed their progress.


Tomato Growing Shopping List


Tomato Guides/Advice


Need more advice?

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