Slow death of old leaves

This has been happening for awhile and I assumed it would probably stop once I got my nutes going but it hasn't. My old leaves slowly turn yellow and necrotic and die and then fall off. I thought it was nitrogen def. but it hasn't really stopped since I've started nutes like 3 or 4 days ago. They start as new growth and look great and then the tips start to brown, then the rest of the leaf slowly dies. They also curl down. Could this be caused by my cup being to small? Is it time to transplant?

Yes your root zone is only like 2" in that party cup. If you want something free or cheap just get 3 plastic grocery bags and put them inside each other and fill it with soil and knife some slits on the bottom and put it on a tray or a bucket lid or plastic baking sheet. Or just buy a grow bag for 50 cents

But how would that cause plant death?

Root bound. Party cups work in scrog because of the holes in cups allow the roots to form in a mass over its reservoir. If your using a party cup for soil purposes your roots will curl into eachother at the bottom or escape and allow light to hit your root sytstem at an early age. By putting it into a larger container you can allow you root s to travel and increase its uptake. Also I have no idea what lights your using but a little CFL or a halogen isnt gonna do much to a plant that size.

Ahhh thanks for the info. Why does light on the roots matter? Light is like always on the roots in non-soil mediums and hydro

haha it's not a little halogen or CFL. I use a 400W HPS. I had to take it out of the grow room to get a good pic cuz the strong reddish light makes everything look orange.

No while I have seen clear plastic reservoirs in Hydro, (like one of those EZ clone displays you see at your hydro store), Its not reccomended. Its never a good idea to let light hit your roots. Your light is more than powerful enough< I would definately shake it out of that keg cup and into a respectable sized pot. I dont know why your using a party cup when have an HID light like that. Pots are cheap man.

well really the only reason is because this is what I sprouted them in and I just never transplanted...