Golden and brown leaf changes on potato, comfrey.

Stonefree

Novice here. I have an allotment with a healthy patch of Setanta potatoes and a very large Russian comfrey. The comfrey was mostly knocked over in a high wind some weeks ago and on cutting it back today I found some of the underneath leaves had this discolouration.

I also noticed today a very similar discolouration on some of my potato leaves. This pic is of a milder one, some were worse and looked like the comfrey. The plot next to mine has similar discolouration on their potato leaves and it's much more widespread. I was initially concerned about blight because I didn't know what it looked like. But some googling and youtubing later, I wonder is it 'drought stress'? One of the YT videos about diagnosing potato diseases had a picture identical to my symptoms. Any help appreciated, thanks.

 

Dovefromabove

I think the comfrey picture just shows mature/old leaves doing what they do.  We're heading for autumn now.

The potato leaves look fine to me - when were they planted?  Are they ready to dig up? 

BobTheGardener

I agree with Dove, both of those look normal.  If you are growing the comfrey for making liquid feed or for using on the compost heap to ensure fast composting, you can cut it back to the ground about 3 times a year and it will rapidly shoot back up again.

Stonefree

Thanks. I did wonder if it was just normal aging. And, I thought I had kept them well watered. Dove, the potatoes were in quite late. I took on the allotment earlier this year with lots of clearing to do, and most things went in later than ideal. They were planted about early June (note for next year-keep a diary!) and are flowering. I had some out last week, at around 2 1/2" long. So I'm hoping they will be growing for a while yet.

Bob, thanks for clarifying that. I have previously cut two buckets of leaves and had a couple of litres of tea. Didn't know you could cut right back though.