Like all plants, trees need water in order to survive. Their massive, deep roots make it easier for them to obtain water when rain is scarce, but even trees can suffer if you don't know when and how to water them properly. This guide will ensure you know how to water your tree from the time it is planted until it reaches maturity.
Right after planting.
Most sapling trees are sold either with bare roots or with only a small ball of soil around the roots. In either case, the roots will be very dry, so the tree will require plenty of water once you plant it. After the tree is in the ground, pour 5 to 10 gallons of water into the soil in a wide circle around the tree. Let it settle for 10 minutes or so, and then dig a little hole next to the tree to ensure the soil is moist. If it is not, add some more water.
During the first year.
It will take your tree about a year to establish an extensive enough root system to harvest water a few feet beneath the surface. During this time, you'll want to keep a close watch on the weather forecast and on the soil around your tree. If the soil becomes dry – or if it has been a while since you've had a good rain – water the tree. Make sure, once again, that you're spreading the water out in a broad circle rather than pouring it all right next to the trunk. You don't want to over-water the soil and drown the roots, so stop once the soil is moist. You can judge this by picking up a handful of soil. It should compact together, but not feel soupy or mud-like.
Once the tree is established.
After the tree has been in the ground for about a year, its roots should be more developed. You should not have to water it nearly as often, as it will be able to reach water deep within the soil even when it has not rained in a long time. The exception is when you're in a true period of drought that has lasted a month or so. You can make things easier on your tree by applying water to the ground around it.
Whenever you're watering the tree at any stage, make sure you don't get the actual leaves of the tree wet, as this can cause scorching and perpetuate fungal infections. You can also apply a layer of mulch to the ground around the tree to lock in moisture so you don't have to water as often. For more information, contact a local arborist.