Gardener's Choice 04/20: onlineclones.ca

Looks to be a manganese deficiency, Leaves may become yellow in between the veins, with mottled brown spots on the affected leaves. These brown dead patches may spread and eventually kill the leaf. Leaves may also shred and fall apart. hope that helps and good luck to you .

Aren't the tips burnt? if so, it's not Ca or not Ca alone. K-def can cause the burned tips and edges along with rust-colored spots. could be an abundance of something else with 2 symtpoms too... check your labels, review what you've done.. eliminate possibilities. then, act... otherwise, there's a good chance you make things worse.

Hello It looks most like a calcium deficiency to me, potassium can lock it out, or it needs a calmag supplement(id recommend adding a supplement it helped me a lot). You can also get phosphorus deficiency along side calcium. But most importantly if the ph is off that can be triggering all of it, with an outside grow its common to have highly acidic soil below 6.3 and that will cause lots of problems. If you have a ph meter scoop some soil into a bowl with distilled water, let it sit 24 hours then strain the water until clear, test that ph and it can give you an idea of the soil ph. Happy growing. ✌️