The foliage continuing to brown may be sort of a "delayed reaction" to either winter damage or abuse while they were at the nursery, depending where you got them from. Some garden centers (okay, technically discount stores) let their nursery stock dry out terribly in between waterings to the point where it stresses the plant. For conifers, the effects of this usually aren't known for a few weeks.

As long as you transplanted carefully all you can do is water well, but let dry out in between waterings as too much water can be just as bad as too dry.

Could it be the plants weren't used to as much sun as you are giving them? Maybe their leaves/foliage are adjusting. Did the transplanting go alright (that is, did the rootballs come out of their black nursery pots easily?) If not it could also be delayed transplant shock.

Whatever the case, I would not fertilize them at this point (some people think fertilizer is a magic cure all for plants). just keep watering regularly but letting dry out in between waterings.

One other thought, maybe check for pests such as spider mites as well.

Glen

A lot of browning is quite normal in late Spring even if unsightly. However, cedars, are finicky on the prairies and even if slightly stressed can deteriorate.

Glen makes an excellent point. We often forget that the northern sun is quite intense this time of year. Few plants thrive at our light levels as the intensity and length of daylight can throw a plant's metabolism out of sync. When bringing home potted plants, let them slowly adjust to full sun conditions.

http://communities.canada.com/calgaryherald/blogs/gardenbuzz/default.aspx

Too much water can be as devastating to your cedars as too little water. If you are overwatering, you will cause the roots to rot, making them unable to take water up to the plant, causing the yellowing, then browning tips you describe.
I assume you are growing these cedars in pots as annuals, and do not expect them to survive a winter in containers. You don't say what type of soil you planted them in. They are often sold in pots of clay, which will repel water rather than absorb it.