Need outdoor grow help! Brown edges all over

[Supersonic]

I have several blue dream, strawberry banana and pink Hawaiian plants growing outdoors in plastic 55 gallon barrels and all of them have something weird going on. I noticed Maybe a month ago that the edges of the leaves , the actual tips of the saw teeth on the sides of each leaf started turning brown and now the leaves are getting worse with that brown moving into the middle of the leaves. I have a few directly in the ground that are doing the same thing. I have them in a planter mix that I bought from a local place that has lots of turkey poop and decomposed tree matter in it and haven’t been using any nutes for the past month thinking maybe it was nutrient burn. They are still growing like crazy and some are over 8ft but the lower portion of most plants have numerous yellow and brown leaves. It seems like the problem is moving up the plants and I would like to get them straitened our before flowering. I water every other day when the soil is dry to about an inch. It has been very warm here but I have a giant porta cooler swap cooler that I turn on anytime it’s 95 or above. I have included several pics. Anyone know what’s going on here??

 

[Supersonic]

A few more pics

 

[Oh gosh]

Pic #2 &4 look alot like a fungus. If your foliar feeding stop and try to keep water from hitting the leaves. I say this because it appears to be on the edges and the tips. When foliar feeding leaves get heavy from the weight of the water. The water is channeled down the veins to the edges and tips. Treat with a copper spray (look online). Only treat one branch on one plant, wait 24 hrs to make sure you don't get an undesired reaction from your plant before treating the entire plant. Cut affected leaf's off and discard away from the garden. Your basically trying to stop the spread at this point. Wait til the suns down before you apply. Nice set up.

 

[Supersonic]

Pic #2 &4 look alot like a fungus. If your foliar feeding stop and try to keep water from hitting the leaves. I say this because it appears to be on the edges and the tips. When foliar feeding leaves get heavy from the weight of the water. The water is channeled down the veins to the edges and tips. Treat with a copper spray (look online). Only treat one branch on one plant, wait 24 hrs to make sure you don't get an undesired reaction from your plant before treating the entire plant. Cut affected leaf's off and discard away from the garden. Your basically trying to stop the spread at this point. Wait til the suns down before you apply. Nice set up.

Hello and thanks for the reply. I had to look up foliar feeding as I had no idea what it was. I have never done this and the plants have actually only been wet maybe 3 times in their lives and this was just when it rained lightly one time and when I sprayed them with a hose once or twice.