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12/09/2012 at 11:22

We have 48 allotments on our site here in Anglesey, and we were hit severly this year with blight. What advice would you give for growing potatoes in 2013, yes we know about rotation etc, we are organic, so limited to soil treatment, please advise.

12/09/2012 at 11:29

If it's Late Blight, the spores don't live on in the soil. The only danger of re-infection is from diseased produce and plant material left lying around. If you get Late Blight again next season it will be a new infection. The spores are airborne, they travel on the breeze, and can travel for miles.

12/09/2012 at 11:34

The blight hit in late June and decimated the late and second earlies crops, most were lucky with earlies.. Potato council confirmed the blight after recieving samples.

12/09/2012 at 13:17

Okay. Presumably the diseased produce and plant material was destroyed. The soil will be fine if you choose to plant again.

12/09/2012 at 15:06

I think most of the country suffered blight this year, On our allotments it affected most gardeners. I always spray my potatos with Bordaux mixture as it is the nearest to being organic as possible.

This year I sprayed first in the last week in June. and then the last week in July but by this time my crop was showing signs of infection. On Gardeners World that week Monty also had blight on his potatos, he said to cut off the tops and lift the crop after a week, I lifted mine three weeks ago and stored them, each week I have tipped them out and checked the condition,Up to now I have only found one infected tuber so am hoping that I have got away with it. The real shame is that due to being lifted approx eight weeks early the size of the potatos are smaller, as usual I grew Desiree this year.

12/09/2012 at 19:37

Thanks so much, Can we put Blight free potatoes such as Cara in the infected ground next year, and also some plot holders are asking about liming the soil over winter.?

12/09/2012 at 21:50

I would guess most of the country have had the right conditions at various times during the year for blight to thrive.

I get alerts from a website called blightwatch.co.uk via e-mail. You probably already know this but it's a service supported by the Potato Council. Traditionally the risk of blight is based on the calculation of Smith Periods. This service calculates the risk of blight down to post codes based on weather conditions and humidity. A Smith period is 3 days of the right conditions for blight to appear. 1 day is amber alert, 3, red alert. If you register on the site you can gain an insight going back several years as to the number of alert's in your area by post code.

My post code for instance has had very few Smith periods for several years and only the occassional  blight alert in any given month This year alerts started in April and reached a peak in July with 15, which believe me is a huge increase in any previous year and the Smith period extended at one point to 5 days with only a gap of 1 day before another Smith period.

Check the site out and see what you think. Knowing when conditions are ripe for blight to thrive is like having an early warning system, I acknowledge you grow organic and can't advise on a product you could use to protect your crop as I try to grow organic small scale in  the garden and would cover my spuds during blight alert periods if they extended beyond 2 days.

13/09/2012 at 07:19
HomemanLL wrote (see)

Thanks so much, Can we put Blight free potatoes such as Cara in the infected ground next year, and also some plot holders are asking about liming the soil over winter.?

Cara is a blight-resistant variety rather than blight-free. There's a difference. They will still become infected if the pathogens arrive on the breeze and the weather conditions are conducive. They will just battle on a bit better than non-resistant varities. But, to answer your question, you can certainly plant them.

I'd only lime the soil if the soil needs it. Spuds like soil slightly acidic. Lime will send the soil's pH in the other, wrong, direction. It's a good idea to invest in a soil pH test kit and test the soil before amending it.

13/09/2012 at 08:34

Thank you all for your feedback

 

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