Richard Bell's Wild West Yorkshire Nature Diary, Monday, 26th July 2010, page 1 of 2
WE'VE GROWN tomatoes directly in the soil in the greenhouse for several years and it looks as if they're now being affected by blight. Leaves are withering on some of the plants and a few of the unripe tomatoes are turning brown, then mushy.
I took the precaution of changing the top 6 or 8 inches of soil in spring when I spruced up the greenhouse ready for this year's crop but I think that next year I'll go back to our old method of growing the tomatoes in buckets of bought-in sterile compost. Although blight can linger in the soil in debris from a previous crop, it's more likely to arrive as an airborne infection. It does look to me as if the affected leaves are those nearest the vents in the greenhouse.
Blight is a fungus-like organism which can infect tomatoes and the related potato in humid weather. We've had high humidity recently and I've also been dowsing the path and soil in the greenhouse twice a day, in order to encourage lush growth. I also opened the door and the vents every day to keep the greenhouse well ventilated.
In previous years our plants have been infected with spotty wilt virus and that's something that can be worse in dry conditions, so it's difficult to get things just right for this crop!
In contrast, our cucumber is thriving in the humidity. We've gone for a miniature variety. The half-size cucumbers are just the right size to last us a couple of days. We should get a few tomatoes too; they're just starting to ripen.
I was late going down to close up the greenhouse one night last week. In the half-light I could see a garden snail and its glistening trail on the concrete pavier path. I'm sure it has appreciated my efforts to keep up the humidity. Checking the salad leaves I found a small handful of slugs and snails, half a dozen of them, which I threw over the hedge into the meadow. They've probably found their way home by now!
In the An Unsung Hero, the biography of polar explorer Tom Crean, Michael Smith mentions the effects of the Irish Famine, brought about by largely successive bouts of Potato Blight in the 1840s. Rather than stay working on small family farmsteads which no longer guaranteed even subsistence, young men like Tom Crean ran away to sea. Crean apparently lied about his age to join the British Navy. The absentee landlords became increasing unpopular, Smith explains, and the feeling that Ireland would be better off as a fully independent, self-governing island gathered momentum.
Potato and Tomato Blight Royal Horticultural Society