Tree watering is a key part of tree care, but it is difficult to recommend an exact amount due to the variety of climates. A few guidelines will help you to water your trees properly.
Watering Newly Planted Trees
For new trees, water immediately after you plant a tree. Usually 30 seconds with a steady stream of water from a garden hose w/ a diffuser nozzle per tree seedling is sufficient.
Watering Trees During First Two Years
During the first couple growing seasons, your newly planted tree is expending a lot of energy trying to get its roots established in the soil. Especially during the first few summers of your new trees life, it will have a difficult time dealing with heat and drought. You can make this easier by providing water and covering the soil with wood-chip mulch. Deep watering can help speed the root establishment. Deep water consists of keeping the soil moist to a depth that includes all the roots.
How Much Water and When
Not enough water is harmful for the tree, but too much water is bad as well. Over-watering is a common tree care mistake. Please note that moist is different than soggy, and you can judge this by feel. A damp soil that dries for a short period will allow adequate oxygen to permeate the soil.
You can check soil moisture by using a garden trowel and inserting it into the ground to a depth of 2", and then move the blade of the trowel back and forth to create a small narrow trench. Then use your finger to touch the soil. If it is moist to the touch, then they do not need water.
If your area constantly deals with drought you will want to consider trees listed as drought-tolerant. Some drought-tolerant species include Arizona Cypress, Japanese Zelkova, White Fir, and Kentucky Coffeetree.
On the opposite side of the spectrum if your area deals with a large amount of moisture or wet conditions, here are a few trees that will do better in wet conditions: Baldcypress, Shellbark Hickory, Red Maple, Silver Maple, Paper Birch, River Birch, and Weeping Willow.
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