Chard leaves wrinkling

I've been growing rainbow chard for years and never had this problem, my chard leaves are crinkling. I can't find any pests like aphids anywhere. Any thoughts? See photos.

 

Could be something wrong with the soil.

 

Are you using the same seeds as before? Many varieties of Swiss Chard have wrinkled leaves.

 

Same seeds as always - West Coast Seeds - Rainbow blend. The first leaves were completely normal chard leaves, these are about the 10th leaves coming up and they look different than the rest - wrinkled, almost dehydrated.

 

hello - did West Coast not change the name - it used to be Aurora and now Rainbow - or vice versa?

in any event, I use West Coast rainbow/aurora chard seeds

and at the coast nr Vancouver BC, i know chard to be wrinkly esp on the plants I have left in the ground for a few years (they survive the winter - and are now bolted) -

also - I notice my 2015 chard is wrinkly - i think it prefers cooler northern climate - which we used to have but not in 2015.

so maybe the heat is a consideration -
I think if it tastes great, enjoy the 2015 wrinkly chard version.
gosh - imagine being a winegrower - every year is an adventure!