Pray for good weather so tomatoes don't play catch up

Technically a fruit but in the public mind a vegetable, the tomato is one of the tastiest and most rewarding crops to grow - if we get a sunny summer

WHEN IRISH rugby captain Brian O'Driscoll recently opined that "knowledge is knowing that a tomato is a fruit, wisdom is knowing not to put it in a fruit salad", he prompted a flurry of media analysis and debate.

The Guardiansniffed and called his comments incomprehensible, likening them to footballer Eric Cantona's musings on seagulls, trawlers and sardines (don't ask), while bloggers scratched their heads and wondered what exactly "BOD" meant. Whatever the veiled meaning behind his words, O'Driscoll was absolutely correct in the botanical sense.

Although for practical purposes it's treated like a vegetable, the tomato - just like the apple, plum or pear - is technically classified as a fruit (as are peas, aubergines, avocados and cucumbers).

Fruit or vegetable, the tomato is one of the tastiest and most rewarding crops to grow, whether you're a space-challenged urban farmer or a country-dweller with a roomy polytunnel.

In the OPW's walled garden in the Phoenix Park, gardeners Meeda Downey and Brian Quinn are experimenting this year, by growing tomatoes outdoors against a very sunny, south-facing brick wall, in a particularly protected (and hidden) spot.

"We call it the cutting garden, and it's a small walled garden within the main walled garden," says Brian. "It was probably once used to house a small melon-house, or something similar. Nothing has been grown here for over 50 years, since the papal nuncio's time, and we haven't even had a chance to properly prepare the soil, so it'll be interesting to see how the plants do.

"We're planting directly into the ground and then mulching heavily with manure. But we're hoping for good results, because it's such a warm spot. The old brick walls get roasting during hot, sunny days, so they act almost like storage heaters."

And this is the thing to remember about growing tomatoes outdoors - they love and demand both heat and light, so will sulk in cool, damp summers and probably succumb to blight. They don't like windy, exposed sites either, so many gardeners prefer to grow them indoors, in a sunny conservatory, glasshouse or tunnel.

Whether outdoors or indoors, you can grow them in hanging baskets, tubs, containers, grow-bags or directly into the ground - but be careful to choose the variety accordingly.

Tomato Types

In the OPW's walled garden in the Phoenix Park, Meeda and Brian are growing four different varieties: Supersweet 100 F1; Rosada F1; Moneymaker; and Ailsa Craig.

"We wanted to grow a few cherry-type tomatoes, which is why we picked Supersweeet and Rosada. Moneymaker is always a good cropper while Ailsa Craig is a reliable old Scottish variety that does particularly well outdoors," says Meeda.

If you're short of space, then tumbling, dwarf cherry-type tomatoes are a particularly good choice for hanging baskets. Look out for varieties such as Hundreds and Thousands, Maskotka and Garden Pearl which, according to recent trials, are three of the best varieties to grow in hanging baskets, producing total yields of up to 2lbs-3lbs per plant although individual tomatoes are tiny.

At the other end of the scale are the huge beefsteak tomatoes, such as the delicious heirloom variety, Brandywine, which can reach a height of 8ft or more, with its large, dark, succulent fruits weighing in individually at anywhere between 1lb to 1.5lbs. And then there are the Plum, Oxheart and Marmande types, as well as the standard round tomato more typically seen for sale in our supermarkets.

Small or dwarf-type tomatoes are usually classed as bush or "determinate" and are self-supporting, while taller varieties are "indeterminate" or "semi-determinate", and will require staking.

There are other factors to consider also - varieties such as Moravi F1 and Matina are relatively fast to crop, while some have better resistance to disease, such as Ferline, Legend and Falcorosso. If you're looking for eye-catching types, there are exotically striped varieties, such as Tigerella and Green Zebra, or beautifully coloured ones, such as the dusky-skinned Black Cherry and the deep yellow Golden Sunrise.

And then you have the conversation-grabbers or just-plain-weird types, like the ghostly-coloured Snow White, or the oddly shaped Green Sausage, which looks exactly as its name suggests. In fact, according to Wikipedia, there are something close to 7,500 different varieties in cultivation, with 125 million tons of tomatoes being produced worldwide last year (China is the single largest producer, followed by the US and Turkey).

Whatever variety you choose, the difference in taste between home-grown tomatoes and those available in shops is both indescribable and unforgettable, as is the intense, tangy, late-summer perfume of a glasshouse filled with the plants.

The only downside comes when you've eaten the last of your own, delicious, home-grown produce and it's back to eating the relatively flavourless, commercially-grown varieties.

Tomato Tips

So how best to grow your own? If you sowed seed back in mid-spring, the young plants should be well-established (as long as you remembered to pot them on) and are now ready to go into their permanent planting positions. If you didn't sow seed, beg a few young plants off keen gardener friends (now is the time when spare plants are often up for grabs).

Alternatively, buy young plants - you'll find them in garden centres although farmers markets, plant sales or car boot sales are often richer hunting grounds if you're looking for unusual varieties.

At this time of year, young plants are often on the point of becoming pot-bound, so it's important to plant them quickly into the ground or into larger pots/containers/grow-bags. Soak the root-ball before planting out into well-manured soil or potting on into good-quality compost, and then individually stake taller, indeterminate types.

As the season progresses and the plants grow, continue to tie new growth to the stake (or suspend from above with string) while nipping out side and basal shoots, although this isn't necessary with bush or determinate types.

And if you're wondering what side-shoots are (see photos left), they are the smaller, secondary shoots that grow at intervals from the main shoot, appearing just above the point where the leaves join the stem of the plant.

If you're still confused, the more eccentric advice is to try standing on your head and imagine something growing out of your armpit. That's the bit of the tomato that you nip out. Just be careful not to accidentally remove the developing flowers also. Basal shoots are those that appear at ground level, next to the main stem. Water regularly, but be careful not to overwater.

As the flowers form, encourage pollination of indoor-grown crops by gently tapping the plants to spread the pollen (best done at midday). Leave glasshouse doors/windows open on warm, sunny days to further encourage pollination and discourage pests and diseases.

Once the tiny fruit trusses start to form or set, increase watering and start to feed container-grown plants weekly with a fertiliser rich in potash.

Vegetable expert Joy Larkcom recommends using liquid comfrey or a seaweed-based fertiliser, and also suggests a maximum of five trusses per container-grown plant (eight if growing in the ground in a tunnel or glasshouse).

Once the taller types have set enough fruit trusses, stop the plant by nipping out the main shoot a couple of sets of leaves above the highest truss. Watch out for greenfly and whitefly (the latter can be discouraged by growing French marigolds close by), and remove leaves below the first fruit truss. Pick the individual fruits as they ripen.

And, finally, pray hard, very hard, for a long hot summer. Without heat and light, the fruit won't properly ripen, as happened last year.

The country now has enough stores of green tomato chutney to last it a decade and there is, to be honest, only so much of fried green tomatoes that one can eat.

Although this week's Urban Farmer in Property was also meant to cover planting out pumpkins, this has been delayed to next week. OPW gardeners Meeda Downey, Brian Quinn and Declan Donohoe were so busy with Bloom 2009 that the pumpkin plants just had to wait

Fionnuala Fallon is a garden designer and writer