It hit 41˚C in the polytunnels yesterday; too hot for people and too hot for crops. Picking starts at 5am to get the cucumbers, salad onions and basil picked and tomatoes side-shooted before it becomes unbearable. Even the bees head for the exit when it reaches 30˚C, as would most humans. I’ve headed to some shade by the reservoir to write this; not a bad office for today.
On our French farm we hire a helicopter to spray lime on the tunnels which is remarkably effective at reducing temperatures and stopping the peppers getting sunburnt; it’s hard to believe, but in the quest for the perfect pepper we seem to have bred out tolerance to the sun. Such is my frustration with overbred veg and overpriced seed that we are experimenting with some older varieties from central Europe this year. Meanwhile our early tunnel-grown runner beans are aborting their fruit in confusion at the extreme heat, so we are yet to pick a bean. We have started picking the first padron peppers which will be available next week; they have so much more flavour than anything available in a supermarket or any tapas bar I’ve visited. Shallow or dry fried until 50% of the skin blisters and sprinkled with sea salt, they are the perfect appetiser.
Even outside the polytunnels the heat is causing stress in many crops, particularly our cool-loving brassicas. Plenty of water can help by affording the plant the chance to cool itself through evaporation from the leaves (as we do by sweating) but in this weather most farmers, us included, don’t have access to enough water pipes, pumps and sprinklers to get around needy crops and back to the start in time. Broccoli has been the worst affected; every head harvested this week ended up being fed to the cows. It was fine when picked but even with the best refrigeration nothing could undo the stress suffered in the field.
Sweetcorn on the other hand is lapping it up; it has a slightly different method of photosynthesis (the C4 pathway) which comes into its own as temperatures rise and water gets scarce. In France we have the biggest, greenest, most uniform crop I have seen in 30 years of growing, and expect to start picking some thumping cobs in early July ready for your BBQs.