Chlorosis?

Just leave it on. Spray in the evening after the bees have left. This will ensure that the beneficial wasps are also gone and give it plenty of time to dry before the sun comes out. Dan it shouldn't damage the leaves at all if mixed properly and sprayed very early morning or evening and I've used it on some delicate alocasia and colocasia leaves. I didn't know about the soap issue. I've never mixed them though. I'll have to reread my label.

Well the brutal answer is 'It's dead'. As to why it's dead it's impossible to tell from the picture. It could be underwaterd, overwatered, overheated, frozen, attacked by a fungus or a combination of several factors. What is the mix it is in and has that pot got any holes for drainage? What do the roots look like? (It won't hurt it to pull it up - it's past any suffering.) October seems a strange time to be starting cucumbers in Canada so my suggestion, harsh though it might appear, is to give up for now. Do some reading over the winter and start again at a more appropriate time.

Alright I'll do so. I actually have to spray my tomatoes with serenade and baking soda mixture on Monday once all this rain is past, so I'll hit the cucumbers with that as well. So far it has worked great for the leaf spot on the tomatoes. It's keeping new growth from developing it too bad and my fruit won't rot anymore (usually) from the leaf spot.my grandma tells me that a tablespoon of baking soda per gallon of water kills off any blight or leaf spot for her as well, better than anything she's tried. I'm going to add that into the serenade mixture. While we're on topic with the compost, @digdirt2, my corn seems to be tasseling really well at this point, and is a beautiful dark shade of green. I did find out that my compost had added fertilizers, as you had discussed in my previous thread about the corn.