Q: In the spring, we planted several new trees and a flowerbed with some shrubs. Now that we are going into summer, how do we water the plants to keep them alive? Is five minutes a day OK? We don't have an automated watering system. We could get watering bags for the trees, but how do we water the flowerbed?
A: How often do plants use water? They use it 24 hours a day. We don't have to water the plants 24 hours a day because the soil acts like a sponge. It holds rain and irrigation water until the plants use it or it evaporates.
In summer across North America, rain usually comes in a few heavy thunderstorms with many hot sunny days in between. Heavy, quick rains mostly run off without soaking into the soil. It is not the quantity of rain from a storm that matters but rather how much of it soaks into the soil. Each week or two, you will need to supplement the rain with enough water to give the plants what they need.
A proper watering soaks down into the soil as deep as the roots can grow. A person walking around with a garden hose rarely stands in one place long enough to let the water soak in deep enough. The person may keep the plant alive, but the roots do not grow deep enough to stop the need for continued watering. Roots growing in a deeper and larger volume of soil have more water available to them, so they can survive longer without supplemental watering.
How good is the soil in your landscape? In most of the country, a good soil that holds water and is 8 or more inches deep will supply enough water for the plants to go without watering for at least a week. If the soil is shallow or sandy, or if the climate is hot and dry, the new plants will need to be watered more often. Five minutes per plant may be plenty or not nearly enough, depending on the soil. Mature, established landscape plants may not need any supplemental water during the summer, or they may if there is an extended drought.
Bags that drip water around tree bases are very beneficial to newly planted trees. Keep an eye on the bags. They can be empty and still have the appearance that they are full. A drip irrigation hose set on a timer can water the flowerbed so you don't need to stand out there for hours.
As the plants grow, the roots expand beyond the base of the plants and the holes in which they were planted. Watering a larger area around the trees will allow the roots to expand into the surrounding soil and not be restricted to the watered soil at the base of the plants.
If a plant looks wilted, first check the soil to see if it is moist. If it is, the plant roots may be drowning. If necessary, plants can be cooled by spraying water on the leaves during the hot part of the day, but don't spray water on the plant in the evening; if the leaves can't dry off before dark, fungal diseases can infect them. If the plants dry out quickly, add several inches of mulch to the area around the roots to help retain moisture.
Email questions to Jeff Rugg at [email protected] To find out more about Jeff Rugg and read features by other Creators Syndicate writers and cartoonists, visit the Creators Syndicate website at www.creators.com.