Extension Educator, Horticulture
We have plenty of garden chores on our November "to do" list; removing dead stalks, composting, blowing all the leaves into the neighbor's yard. Usually watering plants is not on the list. Last fall I was lamenting on how much rain we had. It was tough to get anything done in the garden.
This fall's warm and dry has been the complete opposite of last year's cold and wet. Good news for us, but bad news for perennial plants and trees.
Plants need to be well-hydrated as they enter winter dormancy. Typically we get plenty of fall rains so watering is not necessary. But this year don't put up the water hose just yet.
No one can tell you exactly how much water your plants need. There are just too many variables. It depends on soil type, plant species, and if the plants are well established. During the growing season the general rule of green thumb is that garden plants need about an inch of water a week.
However, once the weather gets colder and deciduous plants lose their leaves they don't require watering as often. Generally plants more than 5 years old should be well established and may not require as much water. Soil around most plants shouldn't be allowed to go bone dry. Keep in mind some plants, such as lavender, prefer dry soil in winter, but dry lovin' plants are in the minority.
You are the best judge on whether your plants need water. Just dig into the soil to determine how dry it is. If the top six inches are dry, than it's time to water no matter what the time of year. Until it is frozen soil should be checked at least every two weeks.
First priority watering list includes: any perennial plants planted this year, any trees or shrubs planted over the last three years, evergreens and broadleaf evergreens such as boxwood and rhododendron. Evergreens and broadleaf evergreens can continue to lose water through their leaves especially in windy areas. Use 3-4 inches of wood chip mulch around trees and landscape plantings to conserve moisture.
Lots of helpful watering devices are available. Most are simply personal preference. Watering, no matter how it is delivered, should be slow and thorough so at least the top 6-8 inches are moist. Soaker hoses are indeed slow and thorough. Place a tuna can under the soaker hose to help determine when an inch of water has been reached. Set a timer and check soil after half hour of soaking to determine the proper watering period. An inch of water will wet an average of 6-15 inches of soil, depending on soil type.
Root feeder devices that attach to hoses can be used effectively to water and/or fertilize trees and shrubs. However proper use of root feeders is needed, otherwise they can cause problems. First remember roots that are active in water uptake are found out at the dripline and beyond and not next to the trunk. In addition active roots are in the upper 12-18 inches of soil so do not plunge the feeder too deep. Also check the water pressure before using the feeder. Use low water pressure. High water pressure can blow large holes into the soil that can cause roots to dry excessively.
If you fertilized your lawn this fall I would also consider watering it before winter. The lawn grass needs some moisture to take advantage of the fertilizer and to survive the drying winds of winter.
Join a bunch of happy waterers. Mail in your Master Gardener application today. Check out our website http://web.extension.uiuc.edu/champaign/ for applications and information on the classroom or online training or call our office for an application 217-333-7672. To find a University of Illinois Extension Master Gardener program near you http://web.extension.uiuc.edu/mg/