When to start fertilizing my plants!

depends on the soil 4 weeks ? ffs 😂

They should be bigger then this by 4 weeks. Something went wrong here. Might want to check your mediums composition and work back from there.

I have used Terra pro alpad of times in the past it's 1 of the best in my eyes. There is some feed within but it's only a light mix so I would definitely give a feed ASAP I wouldn't go mad and fill the whole pot till it's running out, she's still small I would do ring around the base and work outwards the next time this encourages root stretch enticing the roots to search otherwise you could end up with overly wet soil and for to long causing root rot so be cautious of that until the roots are established and then go to a full pot feed.. Grow on and good luck growmie

Yeah bro, at 4 weeks you can definitely start feeding but go super light like ¼ of the recommended dose first time. Watch how they respond for a few days, then slowly increase. Autos can be sensitive early on, so gentle is the key