It is very important to water your newly transplanted tree for at least the first three growing seasons. Watering in the summer months is the most important with its extreme heat and long days. Make sure you increase watering amounts starting around mid /June – July when the real heat starts to set in. Continue the extra care through September as this is the most critical time for transplants (especially leaf trees). A good starting rule of thumb is 10 gallons of water per week for each one inch of trunk diameter. Example: 4’’ dia. = 40 gallons per week (minimum for hot weather). Pay attention to the day time temperature and cloud cover. If it’s in the 80’s – 90’s you need lots of water, if it’s in the 70’s less water, 50’s – 60’s and cloudy/rainy most likely little to no water.
In the hot summer you can water a bare tree with no mulch heavily and it will be dried up within 4 days. A one inch overnight rain will only soak in eight inches. A transplant tree has roots up to four feet deep. Therefore watering a tree is much different than watering shrubs or grass. A drip line is the absolute best way to water a tree because of the large amount of water delivered and allowed to soak in over a long period of time. A drip line is inexpensive and available at Menards in ¼ inch and ½ inch size. We like to spiral it on top of the root ball. Just figure out it’s drip rate as per its emitters, adapt it to your hose, kink the end, turn it on wide open, it’s that simple. For remote areas with no water supply use several 5 gallon pails filled with water with three 1/16’’ inch holes drill in for a nice controlled slow drip. Mulch is also important as it keeps the sun from drying out the root ball. 3-4’’ inches of mulch on the root ball is required and can be put on top of the drip line. Water your trees, then check the moister under the mulch 5-6 days later to see if it is ready for its next watering.