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Dublin: 7°C Wednesday 19 May 2021

Everything you wanted to know about tomatoes but were too afraid to ask

Michael Kelly continues his Grow It Yourself series with tomatoes, a family favourite for soups, salads, sauces and snacks.

Michael Kelly Grower

FEW VEGETABLES HAVE suffered at the hands of the commercial food chain as much as the tomato.

The simple fact is that most of the tomatoes we buy year-in, year-out in supermarkets taste of absolutely nothing. It is often not until you grow your own that you realise this!

The home-grown tomato, on the other hand, is a delectable treat, a meal in themselves, best eaten fresh in the warmth of the greenhouse for maximum effect. Sure tomatoes do require a certain level of TLC, but it’s worth the effort. Get it right and you can be enjoying your own tomatoes from July to November.


There are two types of tomato plants; vine and bush.

Vine (or cordon) tomato plants are an orderly affair and have a tall central stem which produces two types of side stems; trusses or fruit-bearing branches on which the tomatoes grow, and leaf-bearing stems.

Bush tomatoes are more compact but disorderly. They have trailing side branches.

Tomatoes have a long growing season and can be started in February indoors on a heating mat. Otherwise, wait until March.

Sow seeds in pots or module trays indoors in a warm, sunny spot. When they have developed three true leaves, put the plants into 3-inch pots. They won’t be going into the soil until May. Keep the potting compost moist.


Though lots of GIYers have grown tomatoes successfully outdoors, to my mind this Mediterranean vegetable fares best in the warmth of a greenhouse, polytunnel or conservatory.

They can be sown direct in the soil but will also grow well in pots as long as the container is good and deep (tomatoes are quite deep rooting). Grow bags also work well.

Wherever you plant them, make sure it’s the warmest, sunniest place possible. They like rich, fertile soil. Dig in a well-rotted manure or compost before planting or use poultry manure.

Vine tomatoes grow very tall and will require support. An ideal way to provide this is to put strong twine around the roots of the plant before you plant it into the soil. This twine is then buried in the soil and tied to a horizontal on the roof of the greenhouse or tunnel, providing a taut vertical for the main stem to grow up. Leave approx 40cm between plants.

As the plant grows, pinch out side shoots which regularly appear in the angle between the main stem and leaf stems. These waste the plants energy if you allow them to grow.

When the plants are 4ft tall remove the leaf stalks below the first fruit truss. This will improve air circulation around the base of the plants and makes it easier to water. Remove yellowing leaves as they appear.

Water evenly and regularly – irregular watering causes fruit to split. Never water the foliage on a tomato plant as it will burn in the sunlight. Approximate water requirements are 10 litres per plant per week.

Left to its own devices, the main stem of a healthy tomato plant will just keep on growing up and up. But growing tomatoes is a balancing act between allowing the plant to grow to a good height and forcing it to focus on producing fruit.

Keep an eye on the number of trusses that are forming on the plant. If the plant is healthy allow seven or eight trusses to form. If it is not healthy, stop when the plant has formed five or six trusses by pinching out the growing point (top of the main stem).

Once tomatoes are starting to appear, feed the plant fortnightly with a high-potash feed. Liquid tomato feeds are available commercially or you can make your own comfrey tea by soaking 500g of comfrey leaves in 3 gallons of water and leave to stew for a month. Dilute before applying to plants to one part comfrey tea, ten parts water.


Harvest when the fruits are ripe. Fruit will split if left on the plants so remove as it ripens. Surplus fruit can be made into sauces for the freezer.

Later sown plants may continue to produce fruit right into late October and early November.

You are likely to be left with lots of green fruit at the end of the season. Use these for chutneys.

Never serve tomatoes straight from the fridge. The flavour is best when served warm.

Recommended Varieties

Sungold, Tigerella, Sweet Millions, Beefsteak, Roma


The best way to avoid problems is to ensure that air is circulating around the plants. The same blight that affects potatoes can be devastating to tomatoes, particularly outdoor ones (though it can make its way into greenhouses and polytunnels too). It causes leaves to curl and blacken. Try removing affected leaves or plants quickly, but there’s little you can do once it takes hold.

The most common pests are whitefly, aphids and spider mites.

Rolling or curling of tomato leaves is common and can be due to wide variation between day and nighttime temperatures. It is not a problem.

GIY Tips

For effective watering, sink a pot in the ground beside the plant and water into this. This gets water right down to the roots.

At the end of the season put a layer of green tomatoes in a drawer with a ripe apple or banana. These ripening fruits give off the ripening gas ethylene which encourages the tomatoes to ripen.

Bake surplus tomatoes in the oven for 8 hours on a very low heat – cut them in half first and drizzle with some oil and salt. These “sundried” tomatoes can be stored in olive oil or frozen.

Recipe of the Week – Panzanella

This is my version of the classic Italian peasant’s lunch of stale bread and tomatoes. Though purists might sniff at the presence of courgettes, I think it works well if sliced very finely.

I use 300ml of passata to soak the bread instead of fresh tomatoes, but if you have a glut of tomatoes you could, of course, use them instead (rubbed through a sieve).

All in all, it’s not too shabby being a peasant. Serves 4.


  • 300ml organic passata
  • 300g slightly stale sourdough bread
  • 1 small cucumber, peeled, deseeded and chopped
  • 1 small yellow courgette, thinly sliced
  • 1 small red onion, halved and thinly sliced
  • 200g red or green pepper, de-seeded and sliced
  • 20 black olives
  • Handful basil leaves, chopped roughly
  • 10-15 cherry tomatoes, halved
  • 4 tbs olive oil
  • 2 tbs apple cider vinegar
  • 1 tbs capers


Tear the bread into large chunks and put it in a large bowl.

In a separate bowl mix the passata, olive oil, vinegar and season well.

Add it to the bread bowl, stirring well to mix it all together.

Add the olives, capers, courgette, cucumber, onion, tomatoes and basil. Toss it all together again.

Leave it to stand for half an hour to let all the flavours mingle.

Michael Kelly is a freelance journalist, author and founder of GIY.

Read: Magic beans: Make your own hummus with broad beans

Read: For the love of cauliflower: A difficult veg to grow but worth it

About the author:

Michael Kelly  / Grower

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