The Herald - The Herald Magazine
Tender veg Why a hands-on approach will pay dividends come harvest time
NO summer is complete without tomatoes, French beans, courgettes and other wonderful vegetables. Some can be unruly, however, and need to be told who’s boss. In the wild many of these tender summer vegetables are perennials, but their sensitivity to frost means you need to treat them as annuals. Plant breeders have produced fast-developing French beans and tomatoes that are suited to temperate regions with short growing seasons.
They have also selected varieties with a gene that halts upward vegetative growth and starts flowering and fruiting after only a few weeks. These plants have limited or determined growth.
The growing shoot (or meristem) of “determinates” reaches a stage when it stops and acts as a fruiting stem, and the plant’s energies are diverted to fruiting.
Speedy fruiting is an advantage in this neck of the woods, and since bush tomatoes are determinates, their harvest is ready quicker than cordon tomatoes. That’s why I’ve always argued that bush varieties are a safer bet in less favoured parts of Scotland. They can even be grown outdoors where cordons would be impossible.
Even though bush tomatoes fruit early and stop growing tall, they can get out of control and sprawl badly. They need some staking to keep the tomatoes off the ground and away from any grazing molluscs. But, if left unchecked, cordon tomatoes would be even more chaotic. A sideshoot emerges at every leaf node and a jungle of ever-smaller tomatoes is sure to follow. So vigilance is needed to nip off all these tiny stems.
Whenever a tomato’s meristem is terminated, the plant diverts all its energies into producing fruit. And since ripening becomes slower and the fruit less tasty from late September onwards, you may want to cut off the growing point.
Stop the plant two leaves above a fruiting stem, in mid-July, if you grow tomatoes outdoors or a cold greenhouse. In a warm and sunny greenhouse, you could let the plant keep growing for another four to six weeks. You might well end up with green tomatoes, but they’re tasty when fried.
Like tomatoes, French beans have determinate and indeterminate forms: dwarf varieties are determinate and easy to control, but climbers may need to have their growing shoots nipped out when they reach the top of the frame.
Runners are the thugs of the bean family, and to prevent a mass of growth at the top of a frame you must nip out growing stems and look out for colonising side stems.
On the other hand, you know what you’re getting with courgettes. They’ll give you a mountain of goodies and stop after about three months.
Cucumbers, though, are a different story. They produce countless sideshoots and more fruits than you could possibly want. Training and controlling depends on space and needs. I grow a plant inside a frame and let its tendrils cling to supports rather than tie in the stem, which can cause bruising and fungal infection.
Nip out a growing shoot when it reaches the top of the frame and stop sideshoots two leaves beyond a female flower.
Of all the cucurbits, squashes are the most rampant. They’ll smother a huge area in no time. The solution is to define the space the plant is to have and let two shoots develop in opposite directions; curve each to form a semi-circle within the defined area. This curving slightly reduces vigour. Then nip out any sideshoots straying further than you want and only let fruits set along the main stems.