London (change)
12 messages
02/07/2012 at 20:50

I tweeted Thompson & Morgan with a picture of my potatos as I thought they may have blight. They tweeted back saying it looked like the start of it and to try something called bordeaux spray. Can anyone tell me if this is worth the cost i.e does it work?

I've dug a few of the spuds up and theres no tubers or anything just roots.

Any help much appreciated.


03/07/2012 at 06:29

Bordeaux mixture - a blend of copper sulphate and hydrated lime - is an age-old treatment for blight. Like all such treatments, it's preventive rather than curative. There is an issue these days with the copper component. Even though technically organic, it's unfriendly to insects, etc, and will accumulate in the soil. There are other options but they're chemical. I'd talk to a good garden centre about the options.

03/07/2012 at 09:10

i thought bordeaux mixture was only used on fruit trees?

03/07/2012 at 15:07

No, it's also used on grapes, potatoes and other things.

03/07/2012 at 20:43

Another person has now suggested it could be magnesium deficiency! Not sure what to do now!

04/07/2012 at 06:27

Can you post a photo of the problem?

Here are some photos of magnesium deficiency in potatoes. Scroll down to photos 161 and 162 and see if you recognise the symptoms.

Bah! The link system still doesn't work here. Cut and paste this link into your browser:

EDIT. Oooh! The link system is working now. As is the edit system. Happy days!


04/07/2012 at 07:29

Heres the picture I sent T&M and Amatuer Gardener, both came back with either blight or Mg deficiency. Looking at the photos you linked to Italophile it looks like Mg deficiency to me?

04/07/2012 at 08:32

I think you're right. It doesn't seem to have blight's characteristics. Here's blight:


06/07/2012 at 13:14

got it too i think its blight as it has also occurred in my container potatoes but not the ones in my greenhouse.

06/07/2012 at 14:07

my potatoe leaves have gone yellow,splodges of brown on them,then quickly all the leaves fell and died.these are in bags,i got some very small potatoes ,not sure if it is blight?with the awful weather im just leaving them in the bags.i give up.

06/07/2012 at 15:20

Copper suphate and washing sode should not cost anymore than a fiver

06/07/2012 at 15:39

At the begining blight shows as a few single brown spots scattered over your crop.  If you turn the leaf over you will find a dusty white mould growing, these are the spores ready to spread .  A few spots will turn into a lot over the coming week and will quickly show a disease rather than a cultural problem.  Blame the rain and it wont get better as the forecast is poor for the next month so im afraid if you grow spuds and you havent got it yet you soon will have. 

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