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If you are going to water the garden, make sure you do it right.

Deep infrequent watering develops a much better root system for your plants. I recommend 1 - 2 buckets of water per plant every 5 - 7 days.

This is obviously dependent on the size of the plant, but if you remember the size of the plastic container your plant came in, you want that volume of water x 2.

Water should be delivered slowly at the base of the plant with a slow running hose (not the spray setting on your hose attachment) in the mid to late evening.

Watering Established Trees

It's a common misconception that a tree's roots are a mirror image of the aboveground canopy. In reality, an established tree's roots usually extend well beyond the edge of the canopy, or drip line. Although some anchor roots may reach deep into the soil, most tree roots are concentrated in the upper 12" to 18" of soil. When watering established trees, provide a deep, soaking irrigation to the entire area beneath the tree canopy and extending several feet beyond the drip line. Ideally, you should moisten the soil to a depth of 10" each time you water. To prevent rot, don't apply water to the area directly around the trunk.

Know When to Water

The easiest way to check soil moisture is to take a long (8"-plus) screwdriver and poke it into the soil. It will pass easily into moist soil, but be difficult to push into dry soil. If you can't poke it in at least 6", it's time to water. This technique works best in clay and loam soils.

How to Apply Water

Overhead sprinklers are the easiest way to cover large expanses, but they're inefficient, losing up to half the water to evaporation. Trees are better served by watering methods that apply water slowly, right at soil level. It may take several hours to properly water a single mature tree.

A soaker hose applies water slowly so it soaks in rather than running off.

Soaker hoses are an efficient way to water trees because they're porous and release water slowly. Encircle a tree with a spiral of soaker hose and run it for an hour or more — as long as it takes for water to penetrate 6" or 8", using the screwdriver test.

A Pressure Regulator improves the efficiency and prolongs the life of soaker hoses.

Bubblers are hose-end devices that reduce the velocity of the water, so it soaks in rather than running off. Because it waters one spot at a time, you'll need to move the bubbler around.

If possible, avoid watering during the hottest part of the day — 10 a.m. to 6 p.m. — to conserve water.

Frequently Asked Questions

How much water does my tree need? As a general rule of thumb, apply an inch of sprinkler irrigation or enough water to moisten the soil to a depth of 10" or more for mature trees. A common mistake is to apply frequent shallow waterings that don't soak deeply into the soil.

My irrigation system waters my lawn regularly. Isn't that enough for my trees? Probably not. Most irrigation systems are programmed to apply frequent, shallow waterings. Trees do better with less frequent but deeper soakings — a heavy soaking once a week is much better than a shallow watering every few days. That's because shallow waterings encourage tree roots to remain near the soil surface where they're prone to drying out. Watering deeply, on the other hand, encourages deep, drought-tolerant roots.

Should I mulch under my trees? Yes. Grass growing under trees will intercept much of the water you apply, keeping it from reaching plant roots. It's best to keep a large (3' plus), turf-free circle around the trunk. A 2" to 3" layer of organic mulch, such as shredded bark or pine straw, helps conserve moisture and keeps weeds at bay. To prevent rot, don't pile mulch against the trunk.

Should I fertilize during a drought? As a rule, drought-stressed trees should not be fertilized. When water supplies are limited, trees naturally slow their growth. Applying fertilizer can encourage a flush of growth that causes the tree to require more water than is available. And the salts in many fertilizers can harm drought-stressed roots.

Take Steps to Minimize Tree Stress During Drought

  • Avoid digging under and around trees so you don't disturb the roots

  • Don't do any heavy pruning. However, it's OK to remove broken, dead, insect-infested or diseased branches.

  • Keep an eye out for insect pests and disease, because drought-stressed trees are more vulnerable to attack.

  • Avoid using high-nitrogen lawn fertilizers under trees, and never use weed-and-feed products, which can harm tree roots.

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