Brown spots followed by leaf death

My blackjack plants were planted back in mid may and have been fine up until now. Ive been watering them with hose water. Recently small brown spots have been forming on a few leaves and some of these leaves have been turning yellow, brown and then they have been falling off. Also last night a spider forced the top leaves into some nest thing and hatched some spider eggs, but the spider web is doing a kind of lst with the top leaves, bending them over themselves. What is the problem with the leaves and what should I do about the spider webs?

Do you feed you plants any nutrients? They seem to need either calcium and or magnesium, but of course I could be wrong. Personally I love spiders in my grow room unless its a mite! They are predators and prey on insects that could be there to eat your plant, so I welcome the spiders myself.

BC's Finest

I doubt that they need nutes now maybe its a cal-mag defficiency in the old growth, they were looking very good for the weeks that they were outside, just now they are starting to have problems. Did you see what the spider did to the plant in the 4th 7th and 10th pic?

Thought I would give my two cents. I have seen similar spots on non cannabis plants in my greenhouse and they were caused by watering mid day and the full sun burned the leaves where the water spots were left.

Thats really interesting, ive been watering mid day, also the leaves that have spots generally end up falling off. I think the plant is getting rid of all of the damaged stems, because I noticed no new purple stems have been forming as the old ones fall off.

The spider is great, she will keep all the bad bugs off your plant. She will spin her web at night, when flowering you may want to gently move her web off.