We haven’t seen such sustained sunshine in mid-summer for more than four years. The past few summers have been so wet that I started to call June, July and August “the monsoon season”, a time more appropriate for wellies than flip-flops.
The sun has had a peculiar effect on growers, who are marvelling at the spectacle of their plants surging almost before their eyes. A seasoned allotmenteer I chatted to last week was so happy about it that he was practically dancing.
Combined with heavy rain in early June, the heat means the growth surge has been spectacular. Any more of it and I’ll need a machete to get into my greenhouse, where the sun has been magnified under glass to the point where some plants are putting on an inch a day.
This is my first year with a proper greenhouse. I bought it from Argos. At first it was frustrating, because the panels kept popping out at the rate of two or three each day thanks to a weak clipping system. I solved the problem by sealing the edges with an industrial-strength, transparent-rubber solution and glue, and now it’s rock solid.
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And so in May I ordered 20 80-litre bags of compost and four more of farmyard manure and mixed it with topsoil. With scaffolding planks I made raised beds inside, with an 18in-wide walkway between them.
In went the seedlings. I planted between four and eight plants of six tomato varieties, 18in apart, along with two varieties of cucumber. I also planted basil, aubergines and lettuces, and along the edges went jalapeno chillies, sweet peppers and some coriander.
While I realised that the aubergines and peppers would, at first, be crowded by the tomatoes and cucumbers, I figured that once they were trained upwards, I could remove the lower foliage of the tomatoes and let in some light for the lower-ranging plants.
The plants were doing fine until about three weeks ago, when the effects of the heat wave, boosted by a soil soaking inside every two days, caused a growth explosion.
Outside, the courgettes have become monsters that are firing out truncheon-sized fruits at the rate of five or six a day. On the window sill, the chillies have doubled in height in a few weeks and the first flowers are appearing.
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Back in the greenhouse, the centre walkway is now invisible, thanks to the jostling, supercharged foliage. The cucumbers are at shoulder height and the knee-high aubergines, with giant spade leaves, are elbowing their way out of the undergrowth.
The tomato plants are producing truss growth so fast that they’re already looking like main stems before I can find and remove them. The trusses on tomatoes are the secondary branches that start as little sprouts between the main stem and primary branches. If undetected, they soon firm up and redirect the plant’s growth energy into bushing the plant out.
To grow tomatoes in a manageable vertical line, they must be pinched out before they distort the plant’s growth. In a greenhouse, not doing so can lead to overcrowding, which produces the right conditions for fungus and infections.
If your greenhouse becomes overcrowded, as mine has, you will need to take some measures to rectify the situation. First, keep the door and vent open during the day to prevent the build-up of moisture. Tomatoes, as with their relatives, potatoes, react badly to hot, moist air. You’ll know if your greenhouse isn’t ventilated properly because you’ll see condensation building up on the glass or plastic.
I open the vent and the door each morning and close it again when the sun has gone down, because it can still get pretty cold at night, even after a day of blistering sunshine.
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I’ve been cutting out tomato trusses to prevent crowding and I’ve started detaching larger-than-average primary branches that aren’t carrying flowers or fruit. I’ve pulled out the lettuces. They had spread out and hampered the flow of air at soil level. I’ve redirected the cucumbers away from each other.
If it gets any worse (and I suspect it will), I’ll have to start removing entire plants to make room. I’ll chance transplanting them outside rather than throw them away. Tomatoes take to transplanting well enough and it would be a pity to waste a tall vine.
My greenhouse tomatoes are trained up bamboo poles and are attached by loose loops of butcher’s string. These loops move up the bamboo as the plant stretches. The taller the plant gets, the more loops I attach. Most greenhouses are designed with an apex roof, so those plants on the outside nearest the walls will hit the roof first. In mine, the roof is only 4ft from the ground on the edges and the outer plants have already touched it. I’ll prevent them from growing upwards by pinching out the top shoots.
The problem then is that the growth shifts into the body of the plant and it tends to bush out.
The poor chillies and sweet peppers can’t be seen at all. I stuck my head into the thick of the foliage and detected them happily growing away in the twilight beneath the Amazonian canopy.
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Once they germinate and establish themselves — since chillies are tough customers, too — I may plant them outside. In previous years I’ve had them outside until November.
Meanwhile, such is the way with Irish heat waves that, by the time you read this, the rain might once again be streaming down our windows. But better to have flipped and flopped than never to have flipped at all.