I would expect them to stand up straight as their roots establish. I have never trimmed the roots on my onions so I have never seen them leaning. I know Dixondale trims their roots, but theirs are much better established than mine grown in winter under lights.

I had no choice but to trim them, I couldn’t get them separated.

I agree with Tom. I tease the plants out of the container and then slosh the root ball mass around in a bucket of water until almost all of the potting mix is removed. Then I trim the roots of the entire root mass and the seedlings are easy to separate.

If under cover they just might not be getting enough sun exposure. Plants will always 'lean' toward the best light.

Dave

They’re not leaning, they’re “falling”.

The directions with the onion plants that I set out the other day said to set them rather shallowly. I set mine deeper and they stand up straight because they have more dirt support. By bulbing time they will bub a fair amount above ground...YES!

Sorry, you said they were leaning. If they are falling over then they are likely not planted deep enough. You can always brush away soil around them as they get established if you then think they are too deep.

If they are wilting and falling over then - then assuming they have been wello watered - they may be getting to hot under the cover.

Dave

They’re not wilted. I can put a bit more dirt on them.

Why not show us pictures? I bet you have a camera phone.