Ff of and pfp with autos

So newb here on my first grow I used the pot for pot kit I got two foot plants in 2 gallons I used ffof for my second didn’t change a thing i did have the same schedule and nutes But didn’t fight the difficencies I did last time but now I’m only getting 1foot plants same seeds from Ilgm from the same order. Doing it the same time wise tent and light nothings different but the soil. Any advice?

2 gallons is way too tight try 5 gallons/ 15 liters see the extra space as insulation,
afterall the bigger the rootball the bigger the plant the bigger the plant the more weed

caution with FFOF its hot stuff for that I advise adding 25% perlite
add more perlite if you intend to feed your own nutes later in flower
ffof can be re used many times with a little amending (add another small bag each grow)
its expewsnce in places but you save on the nute bottle rip


good luck