I find that different plants respond differently to being potted up. Some guys recover quickly and look great while others take forever. The biggest mistake I see a lot of people make is potting them in regular garden soil, which is fine for short periods but too dense for anything longer than a few days. Greenhouse growers grow their plants in fluffy soiless mixes for a reason - the roots gotta breathe. Most garden soils hold on to too much water and the roots drown.

I use 1/3 peat; 1/3 professional potting mix; 1/3 homemade compost. They must be watered often, and I do use weak solution of foliar, Miracle Grow. I thinks its best to wait several weeks for new roots to begin developing. Some plants need to be foliage pruned, the roots were pruned when dug/seperated. It's also best to know the hort. name and variety too. People who just dig. pot and sell cheap give ones who put some effort into it a bad name.

good ideas here

There is no harm in having a little garden soil in the rootball when potting up garden plants. Some plants like cilantro and dill which are poor potting plants (but ones always asked for)will wilt quickly if roots are exposed in transplanting. Some other plants like mint or chives can be ripped apart and abused and they will still handle the transplant well with a little pruning.

The time to hold potted garden transplants will vary by type of plant too. Unfortunately the plants that seem to bolt the quickest are sometimes the ones needing the longer adjustment period.

I've mixed and matched garden and cell seeded plants and can't tell much difference in the end result. When potting up from the garden you have the added advantage of selecting the better specimen to pot and most perenials will appear more mature, especially if they are an overwintered crop. In either case it is usually best to wait until the plant has adjusted to its new pot and is continuing to show new growth before offering it for sale.