Plants grow sooo slowly at the beginning

I finished up my first harvest from some free seeds I got from a friend. They are sativas. For some reason my first grow the plants grew sooo slow for the first month and same thing with these new ones I planted(same seeds btw). Im at the 3.5 week mark and they are 3 inches tall with only the 2nd set of leaves grown in and the 3rd just starting to grow in. When I say 3rd set I mean the small leaves not even full grown leaves. Each leaf is probably an inch long. Why are they so slow? They look healthy but they are just really slow to get started. BTW my last harvest they ended up being around 4.5-5ft tall.

might be ur soil ur using ive had this same problem if i were u id start em in a jiffy pellet then into a cup of pete moss just a little biger then the jiffty pellet then the roots should be well off the u should have no issues with slow growth thats how im gonna do my next run my wonderrwoman have been a little slow at the beggining

are you using 6500 K light ?

Sorry forgot to mention they're outdoors.

sunlight is too weak now

Same thing happened with my summer grow. And again now. Im pretty sure SoCal sunshine is plenty so thats not the issue.

your plants are growing a root system for the first couple weeks of there lives then they grow a bit then more roots then they grow a bit and so on till they have reached thier potential if you are not using good nitrogen rich soil they be slow also. even outdoors you should suppliment the soil with good soil.

Hmmm yeah that could be why maybe they are trying to establish a root system. Because even last grow they grew way too slow about a month and then took off.