also, stake the trees for the first year. Use something stretchy to tie them to the stake, like strips of T-shirt tied loosely, or the commercial green tape that is made for that purpose. Check the ties several times during the first year and loosen as needed or retie. Don't let them strangle the trunk. You don't say where you are but, this is the general rule for dwarf fruit trees, they need at least 5 gallons of water each per week. More when it is really hot. (rain counts in the total). If these are dwarf trees, then the closest spacing is 10 ft and with the apples that will be close when they grow up. Get a book from the library or read on line at extension sites about pruning those trees starting next year. In most parts of the country, trees are pruned very early in the spring before the buds begin to swell for young trees, where you want to encourage growth. It is not generally a good idea to prune trees just before winter as the wounds don't always heal well. You will want to spread the branches that you keep to a wider angle to make the joins stronger. If you don't you risk limb breakage in the wind after they start bearing. As for fertilizing, that depends on how fertile the ground is where you have planted them and the type of soil you have. Elizabeth is absolutely correct, do not fertilize this year. If the trees are growing fairly vigorously, they don't need additional fertilizer. If the site you choose contains lots of nitrogen, those trees will get much bigger than you expect.