I know potato and tomato blight are related, I signed up to blightwatch which is for potatoes and uses Smiths period to warn of blight risk (2 consecutive days of particular temp and humidity conditions). Does anyone know of the Smith period is also an indicator for tomatoes or do they get it in different conditions?
If so it might be worth checking up the history for your postcode and see if you have even had any full Smith periods yet this year - noting that even if you have it only indicates a risk of blight, not certain blight.
Just to clarify - wet weather isn't the cause of blight, but warm wet weather can create the perfect conditions for the blight spores in the air to settle on the leaves and multiply.
Gardening in Central Norfolk on improved gritty moraine over chalk ... free-draining.
It's fungal, Seb. Spraying with anything is pretty much a waste of time after the plant is infected. Spraying has to be preventive - before any infection. All you can do is remove all the affected foliage, destroy it, and keep an eye out for more.
Fungal spores travel on the breeze and there's no avoiding them if they're around. Early and Late Blight are both common to potatoes and tomatoes and can transfer. If you have spuds in the ground, check the foliage.
As Boater says, things like Blightwatch are only indicators of weather conditions that could be conducive to infection. If the spores aren't around, no problems regardless of the weather. If they are, they will settle on the leaves regardless of weather conditions. Dampness and humidity hasten their progress.
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I know potato and tomato blight are related, I signed up to blightwatch which is for potatoes and uses Smiths period to warn of blight risk (2 consecutive days of particular temp and humidity conditions). Does anyone know of the Smith period is also an indicator for tomatoes or do they get it in different conditions?
If so it might be worth checking up the history for your postcode and see if you have even had any full Smith periods yet this year - noting that even if you have it only indicates a risk of blight, not certain blight.
http://www.blightwatch.co.uk/content/bw-Home.asp
Just to clarify - wet weather isn't the cause of blight, but warm wet weather can create the perfect conditions for the blight spores in the air to settle on the leaves and multiply.
Gardening in Central Norfolk on improved gritty moraine over chalk ... free-draining.
It's fungal, Seb. Spraying with anything is pretty much a waste of time after the plant is infected. Spraying has to be preventive - before any infection. All you can do is remove all the affected foliage, destroy it, and keep an eye out for more.
Fungal spores travel on the breeze and there's no avoiding them if they're around. Early and Late Blight are both common to potatoes and tomatoes and can transfer. If you have spuds in the ground, check the foliage.
As Boater says, things like Blightwatch are only indicators of weather conditions that could be conducive to infection. If the spores aren't around, no problems regardless of the weather. If they are, they will settle on the leaves regardless of weather conditions. Dampness and humidity hasten their progress.