yellowing leaves

I am 34 days into veg and have some yellowing happen,do I need nutes or possibly getting to cold at night,please help

Could be numerous things but most likly nitrogen def.

What's your setup? what are you growing in? Have you started feeding yet?

No,,no nutes,in soil,used FF Ocean Forest,going to start flower nutes in about 2 days,running 2x400 watt lights,4 inch exhaust,temps around 75 when lights on,not sure when off,when and got heater to keep room at 62 at night,mostly yellowing at bottom

Try and add some grow nuets into the formula when you mix. do like a half and half. it sounds like it need N. yellowing from bottom up.