We often have people ask how long they can wait to plant their bareroot items after they are received. The simple answer to this question is immediately. In some cases you are able to wait a few days, but it is not recommended. The sooner the better is a good rule of thumb.
Our boxes actually say to plant the items immediately. We pack our bareroot plants and trees in a moist sphagnum moss to keep them hydrated through the shipping process. Although this will keep them hydrated for several days, it is hard to say how many days the item has been in transit. If an item has to sit over a weekend during the process, then that adds a couple of days to the shipping. This is okay for the plant, but that means that it is closer to needing to get into some soil.
If you receive an item and it just can't be planted for a couple of days, there are some steps you can take to help make sure that the plant is healthy when you can plant. First of all, remove the plant or tree from the box and check to see if the moss is still moist. If it is starting to get dry, you may want to use a spray bottle (with just water) and spray the moss (you won't need to soak it, but make sure it is nice and moist). Next you will want to store the item in a cool place. Basements or garages generally work well. Ideally storage temperature should be between 40 and 70 degrees. These steps should give you a couple of days, but again plant as soon as possible.
Some people decide that they will plant the items in a pot until the ground conditions are optimal. Be very careful with this. Small containers experience drastic temperature variances. They can heat up and cool down a lot fast (and to a greater temperature degree) then the ground. It can take extra care to put plants and trees into a container and transplant later.
Over all, it is possible (in most cases) to wait a couple of days before planting. Planting your new items in the ground outside right away is ideal. Not only will be roots be more protected, this will give the plant or tree a chance to start setting up its roots. The sooner this can happen, the sooner you will see sprouts above the soil (and ultimately growth in height / spread).