I'm not exactly an expert on trees, but I do have 2 Japanese Maples, a Redbud and a couple of cherry trees, so I'll put in my 2-cents' worth (anyone, please feel free to correct me).

Firstly, you do not mention what kind of maple tree seedlings you have. If they're Japanese Maples, you might want to coddle them more, for nothing more than the fact that they're expensive. I think there's no problem transplanting them into a larger pot, but you should only go to a pot which is no more than 2 inches in diameter larger than the pot they're in at present.

If you have any of the hardy native maples, I would transplant them into your garden right away. Be sure to pick the right spot so you won't have to put undue stress on the saplings by having to transplant again later on. I would put a plant ring, trellis or other protection around them so that no one steps on or runs over them with a mower. Other than that, I don't see a problem.

As for earth and fertilizer, just any good garden soil with some added compost, add some bone meal when transplanting, and thereafter, a good high-nitrogen fertilizer (e.g. 30-10-5) or organic fertilizer or compost. Keep well watered well into fall.

I don't know exactly what you mean my the 'oil' in regard to your peace plant, but if you have some kind of bug in the soil, now is a good time to transplant as plants are now well into their growing phase.

When transplanting, you normally do not want to disturb the roots and therefore just pull up the plant with soil attached and place in new pot and soil; but in your case, I would go outside and wash off all the soil and maybe spray the whole plant with a hose (not too vigorously), especially if you see any bugs on the leaves. Then I would use a new or (bleached) clean pot with some nice prepared indoor potting mix, or sterilized soil which has been amended with peat moss, and vermiculite and/or perlite. Since you say your plant has been malingering for the last six months, I would also add some bone meal and starter fertilizer (0-52-10) to give it a boost. If at all possible, keep outdoors for a few weeks in a protected area in the shade and away from the sun.

Hope this helps.

type of Maple: the package didnt say. As I said - 10 dollar 'kit' from the store.

Oil: I meant soil sorry I thought I got all the typos. But I dont think this will survive a 'hose down'. as I also said - small plant. One big leaf and four tiny half-inchers.

Outdoors: They're too small to outdoors. as I said above they are only 1-2 inches tall and as thin as the hairs on my head. I dont think they would survive outdoors yet. I want them to get a little bit bigger first.

I did tranpslant the peace plant. After some difficult googling I also put him into a smaller pot too, fresh soil etc.

Thank you though for your advice.