Tuesday, 26 March 2013

Tomatoes with taste

The popularity of tomatoes as a British garden crop has always slightly puzzled me. They cannot be described as an easy crop to raise in the UK, especially during the last 2-3 cool wet summers. They are hardly a sow-and-forget kind of vegetable, needing regular watering, feeding and checking for pests and disorders.

The reason of course is that if you do beat the odds and raise a good crop, the taste of your own homegrown tomatoes is hard to beat. And your own tomatoes are always much more beautiful and interesting than the usual round Moneymakers you find in the shops. Sow your own and you can grow yellow, orange, striped, pink, chocolate brown, plum-shaped, teardrop-shaped, big, fat and misshapen tomatoes ... the variety seems endless.

At the Secret Garden Club on Sunday, we discussed ways to get the most out of your tomatoes here in the UK. How to sow, and where to plant them out, and how to look after them. We also explained how many growers are turning to grafted plants for bigger and more robust crop, and had a go at grafting our own seedlings.

Sowing seeds
Start them off indoors, any time between January and April. Fill 3-inch pots with seed compost, water well and add two tomato seeds per pot. Cover very lightly with more compost and put the pot somewhere warm and sunny to germinate. You should see seedlings emerge in about a week.

Keep seedlings indoors until all danger of frost is past.

Planting out
Plant outdoors or in a big pot in a greenhouse when they have outgrown the 3-inch pots – when you can see roots beginning to emerge from the bottom, for example. If it's before the end of April, keep one eye on the weather forecast and be prepared to bring your tomatoes indoors if there's any danger of frost.

Indoors or outdoors?
Most tomatoes will grow happily enough outdoors if you find a sheltered, sunny spot. Tomatoes like lots of light, but it is warmth that spurs them on to bear and develop fruit. They hate draughts and wind. They also appreciate a night-time fall in temperature, but won’t stand any frost whatsoever.

The trick when considering whether to grow your tomatoes indoors or out, is to choose a variety that’s suited to the conditions. There are tomatoes cultivated in Siberia (where they have short intense summers) that will be OK in cooler conditions. There are Thai tomatoes (such as the exotically named Thai Pink Eggs) which really should be kept in a greenhouse in this country.
Black Russian tomato - a heritage variety originating from Ukraine.
Most varieties fall somewhere in-between these two.

In the open ground or a growbag?
Neither. After a lot of experimentation I’ve come to the conclusion that it’s better here in the UK to grow tomatoes in pots rather than the open ground or a growbag. 
  • Tomatoes seem to respond well to having their roots restricted.
  • You can control the composition of the soil. Tomatoes like soil rich in phosphorus; specialist tomato compost can guarantee this.
  • You would also hope that the specialist tomato compost isn’t harbouring any soil-borne diseases.
  • You can choose where to position the tomatoes so that they are in a spot that is both sheltered and sunny.
If possible use pots rather than a growbag:

  • Growbags are ugly;
  • It’s difficult to stake the plants properly so they become unstable;
  • Tomato roots like to reach down deep;
  • Watering can be an issue – without drainage hles you can waterlog the plants. Conversely they can dry out easily;
  • Cheaper growbags are very thin and won’t sustain plants through a whole season.
I do buy growbags, however. I tip the growbag compost into pots and throw away the bag.

Types and varieties
What is an indeterminate tomato? A bush tomato?

Indeterminate, or cordon, tomatoes will carry on growing throughout their lives unless you stop the growth (by pinching out the top for example). A wild tomato growing in ideal conditions might grow to 9m and will scramble through undergrowth and around and up trees.

These are the types of tomatoes that need support with a cane or stake and whose side shoots you need to pinch out to encourage fruit production. Otherwise you’ll just get a very leafy plant.

A determinate or bush tomato will only grow to a certain size and then stop. These are the types of tomatoes that tend to grow well in hanging baskets. You don’t need to pinch out any sideshoots.

In a nursery or garden centre, bush tomatoes tend to be labelled as such. If it doesn’t say bush, assume it’s a cordon.

What is a heritage tomato and why are people so keen on them?
Heritage or heirloom tomatoes (Americans tend to say Heirloom, we usually say Heritage) are open pollinated varieties that have been in existence for at least 50 years.

Open pollinated means the plant is pollinated naturally and the resulting seed is true to type.

In other words, if you take a heritage variety such as Pink Brandywine and let the plant fruit naturally, then save the seed for next year, then next year’s plant will also produce Pink Brandywine tomatoes. 

This may not sound very ground-breaking: you plant a seed and it ends up like its parent. But in the tomato world horticulturists have been hand-pollinating and cross-breeding varieties for many years. Hybrid varieties are those which have been deliberately cross-bred, such as Sungold F1. Horticulturalists hybridise tomatoes for a number of reasons: to breed in disease resistance, uniformity for selling in the supermarket, heavy cropping, the ability to withstand cool, damp environments (such as the English summer).

But if you were to save some Sungold seeds, the plants you grow from these seeds the next year may or may not be true Sungolds. And given that Sungolds are deliberately bred for a) their golden colour, b) their uniform cherry roundness, and c) principally for their honeyed flavour, it would be disappointing to say the least, to sow your saved seed and find mostly tasteless fruits in the resulting plants.

One of the best explanations of heritage/heirloom vs hybrids is on Heirloom Tomatoes here: (and click on number 23).

Heritage tomatoes can be prone to disease and some aren’t great when it comes to producing lots of fruit. But they do tend to taste wonderful and many of them have distinctive individual tastes, rather than a generic tomato flavour. This is one reason why grafting is becoming more and more popular: it can help grow vigorous, resistant plants without sacrificing the taste. 

Grafting is a horticultural practice which takes the top of one plant and attaches it - or transplants it - to the bottom of another. The two - the top is called the scion and the bottom, which contains the roots, is called the rootstock - bind together to form one plant, but with characteristics from both the original varieties.

Rootstock varieties are chosen for their vigour and disease resistance (and with fruit trees, rootstocks are chosen to control the size of the mature tree). Scions are chosen for the quality of their fruit. So with tomatoes, you would select a scion that produced delicious fruit and graft it with a rootstock known for producing fast-growing, robust plants.

The resulting grafted plant should give you the best of both worlds: a healthy, vigorous plant producing plentiful fruit.

At the Secret Garden Club we took seedlings of the variety Aegis (from Heirloom Tomatoes) as the rootstock and grafted them with Pink Brandywine and Black Russian as the scions.

The process we used is documented here, with step-by-step photos.

Red Alert, a variety which ripens very early outdoors - you could
be picking your first tomatoes by the end of June.
Tips for top tomatoes
  • Grow somewhere sheltered which gets plenty of light and warmth – a sunny patio, a greenhouse or conservatory.
  • Grow in deep pots.
  • Use specialist tomato compost – the stuff in a growbag is good even if the growbag itself isn’t ideal.
  • Give your tomato plants support, either with a cane or stake, or the greenhouse way with strings suspended from the ceiling and tied to the tomato pots so that the line is taut. Even a bush variety will appreciate some support, unless you’re growing in a hanging basket and deliberately want it to tumble down.
  • If you have an indeterminate or cordon tomato, remove the side shoots (more correctly, axil buds) that emerge between the main stems and the leaf stalks.
  • Water regularly. A good soak every 3-4 days is better than a little bit every day, but check for wilting leaves in high summer (supposing we get such a thing this year).
  • Cut the bottom off an empty water bottle, remove the cap and stick it, cap-end down, into the soil next to the plant. Water into the upended bottle to deliver the water directly to the roots, avoiding leaf-splash.
  • There’s no need to feed until the fruits start forming, then add a dedicated tomato feed once a week (say, with every other watering).
  • As the trusses begin to form, remove the leaves below the lowest truss to maximise the light and air circulation around the plant.
  • Check plants regularly for charcoal-coloured blotches on the leaves or stems. This is blight and it can spread quickly through your tomato plants. Remove any affected leaves or stems you see immediately and don’t put the diseased material on the compost heap.
  • Check plants also for caterpillars (physically remove them) and the developing fruits to make sure they’re not brown at the bottom. This is blossom end rot and it’s caused by irregular watering. Remove the affected fruit and establish a regular watering routine.
  • With all leaf or stem trimmings, whether it’s to remove side-shoots, maximise light or remove blotchy leaves, cut the stem cleanly with secateurs or kitchen scissors to leave as small a ‘wound’ in the plant as possible.


  1. Wonderful post - I'm excited about the idea of home grafting! But tomatoes can be really easy to grow - they've been my most successful crop in these my first 2 years of veg growing. I get seeds from realseeds.co.uk. Their Galina yellow cherry tomato from Siberia did brilliantly last year.

  2. We love Real Seeds too, and its tomato catalogue, in particular, is really good for offering varieties which do well in colder conditions.

    It's good to hear you've had success with tomatoes - here's hoping for a great tomato-growing summer this year too.


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