The short answer
Water a newly planted tree right after planting, then about two to three times a week for the first few weeks. After that, switch to one deep soak a week. In hot, dry weather, water twice a week. Keep this up through the first growing season, and keep giving deep summer soaks for the first two to three years while the roots spread.
How often matters, but so does how much and where. The sections below explain how to tell when a tree needs water, how much to give, and how the schedule changes with western Oregon's wet winters and dry summers.
Why new trees need extra water
A tree from a nursery pot has a small, dense root ball. For the first year or so, nearly all of its roots are packed inside that ball. The root ball often dries out faster than the soil around it, even when the ground nearby feels damp. Until new roots grow out into your native soil, the tree depends on you.
That's why most new tree losses come from watering problems. Too little water dries out the root ball. Too much water, especially in clay, drowns the roots. The goal is steady moisture in the root zone, not a soggy hole.
A simple watering schedule for new trees
Use this as a starting point. Then adjust based on weather and how your soil feels.
| Time since planting | How often to water |
|---|---|
| Planting day | Water deeply to settle the soil |
| Weeks 1 and 2 | Every two to three days if there is no rain |
| Weeks 3 to 12 | About twice a week |
| Rest of the first season | Once a week, twice in heat waves |
| Years 2 and 3 | Deep soak every one to two weeks in summer |
Rain counts. If you get a good soaking rain, skip that watering. A light sprinkle that only wets the surface does not count.
How much water to give
A common rule of thumb is about 10 gallons per inch of trunk width, measured a few inches above the soil. A small tree with a one-inch trunk needs about 10 gallons each time. A tree with a two-inch trunk needs about 20.
The easiest way to deliver it is slowly. Set a hose at a slow trickle near the root ball for 15 to 30 minutes. You can also use a soaker hose coiled around the tree, or a five-gallon bucket with a few small holes drilled in the bottom. Slow water soaks in. Fast water runs off, especially on clay or a slope.
Where to water
Aim at the root ball first. For the first few months, that's where the roots are. Water poured only at the edge of the planting hole may never reach them.
As the tree grows, widen the area you water. By the second and third year, water the root ball and the soil out past it, toward the edge of the branches. This pulls roots outward and builds a stronger, more drought-tolerant tree.
How to tell if your tree needs water
Don't water on a strict calendar alone. Check the soil first. It only takes a minute.
- Dig in 2 to 3 inches. Push a finger or a trowel into the soil right at the root ball.
- If it's dry, water. Dry, crumbly soil at that depth means it's time.
- If it's damp and cool, wait. Check again in a day or two.
- If it's soggy or smells sour, stop. Let the soil dry out before you water again.
A long screwdriver works well too. It slides easily into moist soil and is hard to push into dry soil.
Signs of too little or too much water
The symptoms can look alike, which is why checking the soil matters.
- Too little water: Leaves wilt in the afternoon, curl, or turn brown and crispy at the edges. Leaves may drop early in summer. The soil is dry well below the surface.
- Too much water: Leaves turn yellow or pale green, then drop. New growth looks weak. The soil stays wet for days, and water may pool around the trunk.
If leaves wilt but the soil is wet, cut back on water. The roots may be short of air.
Oregon notes: wet winters, dry summers and clay
Western Oregon has an unusual pattern. Most of our rain falls from fall through spring, and summers are long and dry. That changes your watering plan through the year.
- Fall planting: Water weekly until steady fall rain starts. After that, the rain usually takes over. Fall is a great time to plant here for that reason. Our guide on how to plant a tree covers timing and depth.
- Winter: Most new trees need little or no water. Check only during long dry spells. Bare root trees go in during this season, and our bare root planting guide explains how to water them in.
- Spring: Start weekly deep soaks once the rain tapers off. This is often in May, but it varies year to year.
- Summer: July through September is the hard stretch. Plan on one or two deep soaks a week, and more during heat waves. A tree planted last fall still needs this help its first summer.
- Clay soil: Much of the Willamette Valley sits on heavy clay. Clay holds water a long time and drains slowly. Water less often but deeply, and always check the soil before you water again.
Tips that make watering easier
- Mulch. Spread 2 to 4 inches of wood chip or bark mulch over the root zone. Keep it a few inches off the trunk. Mulch slows evaporation and keeps roots cool.
- Build a water ring. A low ring of soil around the root ball holds water in place so it soaks down instead of running off.
- Water in the morning. Less water is lost to evaporation, and leaves dry off during the day.
- Skip the lawn sprinkler. Short, frequent sprinkler runs wet the surface but rarely reach deep roots. Give the tree its own deep soak.
- Hold the fertilizer. Fertilizer won't fix a watering problem. Let roots settle first.
Frequently asked questions
How long should I water a newly planted tree?
Use a slow trickle from a hose for 15 to 30 minutes at the root ball. Aim for about 10 gallons per inch of trunk width each time. The goal is to soak the root zone deeply, not just wet the surface.
Can you overwater a new tree?
Yes. Overwatering is common, especially in clay soil. Roots need air as well as water. If the soil is still wet 2 to 3 inches down, wait before watering again.
How long do new trees need extra water?
Plan on regular watering through the first full growing season. Then keep giving deep soaks during dry summers for two to three years, until the roots have spread well beyond the original root ball.
Get help with your new trees
The Nursery Outlet grows trees at our nursery in Woodburn and serves homeowners and landscapers across the Willamette Valley, from Salem to the Portland metro area. If you have questions about watering, soil or which tree fits your yard, contact our team or stop by the nursery. We're happy to help your new tree get off to a strong start.