Blight warning
Posted: Sun Jul 29, 2018 7:19 pm
I subscribe to Blightwatch, which tries its best to give you a heads up of imminent blight attacks based on the weather forecast.
However, it has a habit of getting the forecast wrong and rewrites its warnings, just when you think nothing will happen... And that's just happened.
Saturday, which was exceptionally windy, was one of its Hutton criteria days, with six hours of hummidy over 90%. Today, that will be eight hours and tomorrow eight hours. All bad, since six is the threshhold for attacks (it used to be 10 under the former Smither period warnings).
I would have loved to spray with copper mixture today, Sunday, but it's been raining on and off all day and is forecast to continuing doing so for the rest of the evening, so spraying is a no-no, since the copper mixture will just get washed off.
Monday, when we're to get another eight hours of humidity, is also a blight day.
My question is this: is it still worthwhile spraying with copper mixture around Monday lunchtime, which is when I'll be free to do so and when there won't be any rain? Will it be too late, ie just after optimum blight conditions are fading?
I have loads of tomatoes and potatoes in situ that will die if I get this wrong.
However, it has a habit of getting the forecast wrong and rewrites its warnings, just when you think nothing will happen... And that's just happened.
Saturday, which was exceptionally windy, was one of its Hutton criteria days, with six hours of hummidy over 90%. Today, that will be eight hours and tomorrow eight hours. All bad, since six is the threshhold for attacks (it used to be 10 under the former Smither period warnings).
I would have loved to spray with copper mixture today, Sunday, but it's been raining on and off all day and is forecast to continuing doing so for the rest of the evening, so spraying is a no-no, since the copper mixture will just get washed off.
Monday, when we're to get another eight hours of humidity, is also a blight day.
My question is this: is it still worthwhile spraying with copper mixture around Monday lunchtime, which is when I'll be free to do so and when there won't be any rain? Will it be too late, ie just after optimum blight conditions are fading?
I have loads of tomatoes and potatoes in situ that will die if I get this wrong.