Hey man, I'm not sure if this is the problem or not, but it could be from nitrogen toxicity all though your plant doesn't have the dark green that is generally associated with that problem. Do you have a fan in the room blowing on that side of the plant? I was looking around for other possible things it might be, and Wind burn came up. It says that sometimes if a plant is being beamed with a good amount of wind that it could cause the leaves on the side where the wind is greater to have curl tips compared to those on the opposite side. I hope you figure out man because your garden is looking good. Good Luck
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