Fall is an excellent time for planting and transplanting, provided there is adequate soil moisture to allow plants to reestablish their root systems. Because inconsistent watering or lack of rainfall during this crucial period can rapidly cause a new planting to fail, it is well worth your time to learn a few tricks to make watering easier, more efficient, and more effective.
A good general guideline for the first year after planting is this: If rainfall is less than an inch per week, provide supplemental water. During the winter months, when the ground is frozen and deciduous plants don’t have foliage, watering is generally not necessary. However, you may wish to water occasionally in winter if there is an unusually warm or dry spell and the ground is not frozen.
Deep watering is the key to strong roots
Effective watering encourages root systems to penetrate deeply into the soil. If you water quickly and shallowly, only the top few inches of soil will be adequately saturated, and roots will remain near the surface.
The texture of your garden’s soil will affect how much and how often you will need to water. Sandy soil that is low in organic matter can become hydrophobic and repel water if it is allowed to completely dry out; in this situation a very slow and long watering period will be needed to remoisten the soil. Soil with a high clay content can also be difficult to rehydrate if it is allowed to dry out; when it is oversaturated, the tiny pores between soil particles remain wet for extended periods. A soil composition test from your local extension agency will provide information on the makeup of your garden soil, which will allow you to adjust your watering efforts accordingly.
A watering bag is a great solution for newly planted trees
If you are not a fan of moving sprinklers all day, there are options for you. Gator bags are ridged plastic pouches that zip together and hold a large amount of water. They stand on their own even when unfilled. Each section has small perforations at the bottom that release the contents slowly over many hours. They are ideal for large balled and burlapped trees or large container specimens.
Watering doughnuts are ideal for smaller trees or shrubs. They are similar to gator bags in the way they distribute water, but they hold less water and have a lower profile.
No matter which method you choose, remember that slow and deep watering is best. If you are unsure if the entire soil profile is being adequately saturated, dig down at least 6 inches to check the moisture content of the soil an hour or so after application.
Frequent observation and physical inspection of plants and soil is very important. By becoming familiar with your soil type and plants’ needs, you can generally avoid emergency situations and have a happy, healthy garden that will thrive for years to come.
For even more watering strategies, check out: A Guide to Garden Watering Systems and Strategies
If you’re installing new trees or shrubs, check out: Two Tree Planting Pitfalls to Avoid
For tips on building and maintaining healthy soil, check out: Put the Life Back into Your Soil
Adam Glas is a garden supervisor and rosarian at the Scott Arboretum of Swarthmore College in Swarthmore, Pennsylvania.
Photos: Adam Glas