Can I grow tomatoes outside?

Most gardeners grow tomatoes in a greenhouse or polytunnel, as these plants do best in warm temperatures. This can make growing them outside difficult for some growers, but if you can provide them with warmth, shelter and sunshine they will still thrive.

There are various ways you can keep your tomato plants toasty and warm. The easiest is to choose your location carefully and make use of stone walls. If you have a sun-trap of a garden, then you’ll find you can grow pretty delicious tomatoes. Just pop your plants in a spot that gets maximum sunlight and is sheltered from the wind. In a town or city location this is often very easy as temperatures tend to be warmer overnight. Perfect for tomatoes!

Even if you don’t have a walled garden, you can still get really good results by growing tomatoes against a south-facing wall. The wall will heat up during the day and reflect the heat at night, thus keeping your tomatoes quite nice and warm.

If your site is fairly exposed and you can’t find a sheltered spot, then the best option is to choose a dwarf variety (like Tiny Tim) and keep the plants covered with a cloche. When the plant is flowering, you’ll have to remove the cloche for a couple of hours during the warmest part of the day to allow pollinators to get to work.

You could also purchase a grow bag ‘grow house’ – which is a makeshift plastic greenhouse that can be attached to a grow bag. However, this option comes with a word of warning – in our experience they don’t stand up well to wind, and can tear very easily on a windy summer’s day.

However you choose to grow your outdoor tomatoes, there are a few things that will give you better success:

  • Keep them well watered – the soil/compost should be kept consistently moist.
  • Give them a fortnightly liquid feed once they start flowering
  • Make sure pollinators have easy access to the plants
  • Pinch out the growing tips of upright (cordon) tomatoes when the plants reach head height.
  • Be quite brutal in pruning off foliage once the plants have plenty of flowers and fruit as this will encourage them to focus energy on the fruits and not on the leaves
  • If growing upright/cordon tomatoes in pots, bear in mind that most garden centres will sell 5 litre pots as “tomato pots”, but you will get much better results from a slightly bigger, deeper pot. A 7.5 litre to 10 litre pot per plant would be a good choice (dwarf plants are ok in the 5 litre pots though)