ok to plant seedlings with minor fungus gnat infestation?

I've been growing seedlings indoors for the last 5 or 6 weeks and now am hardening them off by taking them outdoors a few hours each day. Problem is: I have a bit of a gnat infestation. I've mostly been handling it with these yellow sticky traps which does catch them but I do see occasionally one or two of them flying around.

What will happen when I plant these seedlings outdoors in the garden? I'm concerned that they could potentially infest the rest of my plants in the garden. I'm hoping the gnat larvae can't survive outside, or have natural predators there that they don't have inside. Thanks for any thoughts.

My experience has been that the fungus gnats go away when the plants go in the ground. It wouldn't hurt to keep some of the sticky traps around for a while after the plants go in the ground.

Have you tried misting your pots' surface with dilute hydrogen peroxide?

Someone said that coffee deters many insects in pots. I usually wrap the coffee filter around my grounds and let them dry a little before I drop them in my save-for-composting tub. If I ever had insects in pots, I would park one of those wads of wrapped-up-coffee-grounds on top of the soilless mix in each pot, just to see if it kept them away.

I sprinkle some coarse pine bark shreds on top of my seedling trays, after the seedlings emerge. It keeps the surface drier, which discourages damping-off fungus and maybe fungus gnats.

Or try putting a small fan on them when indoors. That in itself will harden the plants a little, if your household air is dry. It it might also deter gnats. (Part of hardening off is teaching the leaves to close their stomata when there's a dry breeze, so the plant doesn't wilt. A dry draft or a fan in dry air will teach an indoor plant how to conserve moisture.

Thanks, folks. About half of the seedlings are now planted in the garden, and they look fine.

They won't be any problem outside. It's indoor conditions that can encourage them, in my experience. There may be a few outside -- that's where they came from, in all likelihood -- but I think their numbers have to be pretty substantial to do much damage. I don't worry about seeing just a few.