A friend recently lent me a copy of Pikmin, and I’m enjoying it.
I’m on Day 3, and I can’t get any Yellow Pikmin to spawn. I activated the Yellow Onion, but all my Pikmin insist on carrying everything to the Red Onion. I don’t know what I’m doing wrong…how do I get them to make Yellows?
Pikmin will automatically favour the onion that is the same colour as them. To get more yellows to spawn, simply ensure that it is only yellows that are carrying the pills/bug carcasses back to their onions.
And you only need a couple dozen of them, anyway. Concentrate on getting 100 red flower pikmin first. 
I had about 90 Red flowers when I found the yellow onion. But now I need to blow shit up.
Thanks.