watt of the led for grow box 40x40x120cm

how many watt should i use?during the growt of the plant wich parameter of PAR and Lumen should i follow, and how can i adjust the distance betwen light and the top of the plant, I want to know like how many cm of distance i have to respect during the various stage of the grow, both in feminized plant and autoflower
thanks to everyone

Welcome, Aisenberg
That's a really small area to work with.
You have about 2 sq ft of area, so 60-80 watts of decent diodes will give you enough light.
A simple solution would be a single 3500k QB panel on a 120-watt driver and then dim it for your space.
You're going to have to keep the plants REALLY squat because you don't have much headroom.
A QB panel will let them run the closest.
I use a 4000k v1 QB on a 120 watt driver in my 1.5x2.5x4 mother tent.

stavo pensando di prendere un 40x40x140 invece di 120, ora ti faccio vedere il led Spettro completo che pensavo di prendere e dimmi la tua opinione
Grazie per il benvenuto