“I installed a new garden last year and would like some advice on best practices for watering this spring.”
— Gabriela Alvarez, Park Ridge
Soil conditions in many gardens are running on the dry side this spring, so giving your new plantings more focused attention in the coming weeks is a good idea. The recent warm and windy weather, for example, did speed up the drying out of gardens.
It’s difficult to give you specific instructions for watering, as there are many variables based on a garden’s growing conditions. Gardens with sandy and well-drained soils need more frequent watering to get plants established, as the soil dries out more quickly than heavier clay soil.
Different types of plants prefer different levels of moisture, too. Perennials planted in a shady zone, for example, may be competing with tree roots for water. The amount of sun and shade will also influence how much water is needed for those garden areas. Different zones of your garden may dry out at different rates.
The established plants that have been growing for more than three years in your garden are most likely fine and do not need supplemental watering at this time. Many plants that have been installed over the last three years can benefit from additional water this spring and summer, with those planted last year getting priority attention. I just watered some shrubs I had planted early last fall, since there has not been enough rainfall to water them adequately for their stage of establishment.
Spot check the soil at the base of your plants to see how much soil moisture is present to guide you in whether or not to water. Water stress is harder to see in the foliage during the early spring season. Use a hose to water at the base of trees and shrubs that were planted while balled and burlapped to thoroughly moisten the root balls during the first one or two years of establishment.
You should not rely solely on a sprinkler system. Even recently installed perennials benefit from an occasional deeper soaking with a hose while they are getting established in their first couple years. The foliage of evergreens can shed water from a sprinkler to the outside of the root ball, leaving it dry. As the tree becomes established over the first two to three years, the roots will grow out into the surrounding garden soil.
Generally, one thorough watering a week will suffice for new balled and burlapped plants during the first year. Also monitor to make sure you are not overwatering, as I have seen gardens with sections that are very wet with soggy soil even during dry periods — a sign of overwatering, which can also stress and kill plants.
If you are using an automatic sprinkler system or watering with a sprinkler attached to a hose, be sure to check that all the plants are getting adequate water by monitoring the soil and spot checking the plants’ root balls. Don’t assume that your sprinkler system is providing the right amount of water. Monitoring the plants and the soil moisture will help you provide the optimal amount of water for your new garden plants.
Many gardeners are seeding lawns now. Proper watering is critical to having success with seeding, and I see many gardeners fail at this. The grass seed needs to be kept moist with frequent light watering one to three times per day until it germinates in approximately two weeks. Letting it dry out during this time can dramatically reduce germination of the seed. A light layer of compost can help retain moisture for the seed.
For more plant advice, contact the Plant Information Service at the Chicago Botanic Garden at plantinfo@chicagobotanic.org. Tim Johnson is senior director of horticulture at the Chicago Botanic Garden.