When to start Flowering nutes???

Ok I just bought a 500 ML of bud candy and big bud from Advance nutrients to try with this grow. My question is when do I start using them once I switch my lights to 12/12? Also do I need any thing else far as nutrients go? During veg stage I was using cal/mag+ and some cheap water soluble nutes from eBay that was 20-20-20. I know that's strong but I used at a weaker strength. Also what should my ppm be? my babies are at about 1 foot I'm tryna flower now cause my tent is only 4 feet high so space is limited.

When I switch to 12/12 I feed half veg nutes and half bloom nutes for the first couple weeks. This helps reduce the stretch and helps maintain green leaves. I gradually cut back on veg nutes as the flowering stage progresses. If you only have 4ft of height definetly give them the veg nutes to lessen the stretch. Good luck!

Ok great thanks