Hi everyone! I just planted my broccoli seedlings this weekend. I mulched lightly with straw. And I just noticed today that there are holes being bitten in the leaves. I looked around to see if I could see any bugs, but I didn't see anything.

Does anyone know what this is, and how I can organically treat these babies so I don't lose them?

It's probably the caterpillars of white cabbage butterflies. They're light green, and hang out on the backs of the leaves. The eggs are laid one at a time and are a light yellow. You can either hand pick or spray with bt. I started using row covers on the broccoli and it really works! No caterpillars.

Little black bugs 'popping' around? Flea beetles are out now and eat tiny holes.
Slugs hiding in the mulch? Sometimes they cruise up the stems and chew off the leaves.
I think there are other nightime beetles that will eat the leaves off.
Garlic spray with a little cayenne+soap?
Pull the mulch away for awhile until the temps get hot?