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Sweet peas have succumbed to powdery mildew again


for 3 years I have grown sweet peas from seed and every year by July/ August the plants have died off from this powdery mildew (I think that's what it is).

The first year I got great healthy plants and even they succumbed. I haven't managed as well the last 2 years but regardless by July August I'm looking at dried up plants- not because they havent got water but due to this mildew thing.

I only water them at the base if its really dry...

Can anyone advise? Im in S.E London and they have a nice sunny spot but tried some in shadier spot and same thing happened....I do love these blooms and have been buying good quality seed...


Thanks image


  • fidgetbonesfidgetbones Posts: 16,538

    More water while they are growing. Don't wait until they are dry.

  • cathy43cathy43 Posts: 373

    Try planting them in different places in the garden each year, they are greedy plants and deplete the soil and add plenty of manure to the planting hole.

    Agree with Fidgetbones, greedy for water as wellimage

  • DovefromaboveDovefromabove Posts: 82,797

    Some people are confused about powdery mildew and think it's caused by the plant being too wet ... it's the opposite - powdery mildew attacks plants that are weakened by drought.

    A bucket full of water every rain-free day in the summer wouldn't be too much. image

    “I am not lost, for I know where I am. But however, where I am may be lost.” Winnie the Pooh

  • Powdery Mildew can be kept in check by a monthly spray of  'Systhane' (available from most GCs) applied from June until the end of flowering.

    Dry conditions and lack of air circulation are the main causes of mildew in SPs.

    Poor air circulation is usually as a result of planting too densely. Dry conditions can be helped by watering the foliage regularly.   

  • Hi,

    Thanks for the advice. I didn't realise that nutrients would be an issue when in the ground. I've been meaning to put some rotted manure down anyway so Ill do that this autumn.

    I guess I'd been trying not to water them overly as I thought thats what caused the powdery mildew!

    Ill have a little rethink for next year. I also noticed that Sarah Raven does a comfrey feed apparently especially good for sweet peas so Ill try that too next year.

    Thanks again!


  • Mel MMel M Posts: 347

    On the RHS web site they state that Bayers Garden Systhane Fungal Fighter and Bayers Fungal Fighter Disease Control has to be withdrawn from sale by the 30th of November 20015 and all stock used, or disposed of, by 30th November 2016. Vitax 2-1 Plant and fish oil is also to be withdrawn. I have used Bayers on my fruit trees and found it excellent. For powdery mildew I use 1 dessert spoon of baking powder disolved in 1 litre of water. It is as good as anything so long as you spray at the first sign of the disease, or even before. ( The websites recommend potasium bicarbonate mixed with water - probably the same thing!)

  • Mel MMel M Posts: 347

    Just been browsing the web and it seems that Bayer are bringing out new formulations to replace the items being withdrawn from sale.

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