Is that full-strength Miracle Gro? If so, could be salt burn from overfertilization. Kale is not a heavy feeder and does not need MG once a week.

Yes I mix it full strength per the instructions, salt burn huh? Boy I hope so that would be an easy fix! Thank you very much for the input, any other ideas? I've posted another picture of a different plant.

I agree that you are over feeding. And the leaf seems strangely shiny. Is it wet? If not it's weird. And are they growing in grass?

I actually just sprayed some safer brand insect killing soap on a few plants that had cabbage loopers on them which is why they look shiny. The cabbage looper marks are clear and obviously insect related and I don't think they have anything to do with the grey spots. They are not growing in grass I just use grass as mulch to keep the weeds down, I've used it in my garden before without any issues so I don't think it's related to the grass either but if it's possible let me know, I want to keep my kale plants strong! Thank you for your answer and do you still think it's over feeding based on the new information?

Yes - the overfeeding idea is based on your saying you fed them every week at full strength. I don't know if it's causing the grey patches but it just isn't necessary.

I thought the grass looked as if it was growing rather than lying on the soil. Could you show a picture from further back so we can see the general state of the plants?

The picture is flipped for some reason but if your looking at it the way it's intended to be looked at the top is Winterbor and the bottom is Vates blue curled Scotts

Anyone else have any ideas?

What temp was it when you sprayed the soap and was it in the middle of the day?

Pesticides shouldn't ever be applied when temps are above 80F or the sum of the temp and humidity is >140. Insecticidal soap, in particular, should be applied at dusk(preferably), and then rinsed off in the morning before the sun can damage foliage.

Also, insecticidal soap does nothing to loopers. Use BT K variant--- totally organic and effective on caterpillars only. Available anywhere. Follow label instructions. Here's the thing though--- I get loopers constantly and though they get to my other brassicas, they leave my KALE alone.

Regarding fertilizer burn. Could be. Did you foliar feed? Agree with flora -- kale doesn't need anything past some decent soil and some compost.

Kevin

I applied it at night per the instructions when it was cool outside. The stuff I have said it would work on loopers, but who knows they seem to be gone now that I have sprayed the kale could just be luck though. If they come back I'll use what you recommended. As for feedung I used a miraclegrow spraying can that hooks up to the house. The leaves that have the grey on them aren't dead it's just the outer rim of them and the plant is still growing and looks fine its only when you get up close that you can really see it and some of the burn is in the center of the leaves as well.

I'm still not sure if you are foliar feeding but it sounds as if you are. Here's a quote from the RHS: 'Foliar feeding: This is the application of a dilute solution of fertiliser to the leaves of plants, useful as an emergency treatment for correcting nutrient deficiencies or for providing quick supplementary feeding. Foliar feeds should not be applied in bright sunlight because the foliage may be scorched.'

Note that foliar feeding is an emergency technique for when something is missing and it should be dilute.

As a matter of routine is not required and is essentially a waste of time and money. Kale is tough stuff and if it does need feeding because your soil is in some way deficient an occasional application of a general fertiliser around the plants is sufficient. Personally, I never feed kale as the soil is full of compost and has an annual load of manure added.

Here's an idea. Clip all affected leaves but make sure you leave the center ones alone. Kale grows back so fast, you'll probably only go a week without. Besides, you look to have enough plants to feed the whole town. Looks like you could use some heavy mulch also.

That hose end sprayer... trash it or save it for dormant oil spraying on a fruit tree or something. Or something else. Foliar feeding is not recommended in my book unless it's something like worm tea or compost tea. And ESPECIALLY not recommended with synthetic ferts.

With kale, feed the soil early with organic matter and MAYBE a side dressing with more later in the season. Or... if you really feel you need some, maybe some fish ferts and or a dash of organic meals. Kale with do well in pretty poor soil.

The pesticide you used sounds like it's broad spectrum. I recommend against them since they kill the good bugs also.

Good luck

Kevin