The 2018 gardening season may be slowing down but it is far from over. As September approaches our yards and gardens still require and deserve a lot of attention. There many “chores” that are best done in the cooler fall months of September and October.
Lawns: The best thing you can do for your lawn this fall is water. Your lawn requires 1” to
1-1/2” of water per week, including rainfall. If we continue to experience the temperatures in the high 80s and 90s that we had in July and August, lawns will require even more water because so much of the moisture will evaporate. How often to water depends on the amount of rainfall we get and on the soil type. Sandy soil drains readily so that much of the water will drain down to below the root level; in this case it is better to water 1/2” 2 to 3 times per week. Loamy or clay soil retains moisture better so a weekly soaking of 1” will suffice, just be sure that the soil is not so saturated that water is standing on the lawn. If at all possible, water in the morning to reduce the potential of evaporation in the heat of the day and turf disease.
Mid-August to mid-September is also the best time of the year to reseed or overseed a thin lawn. September is a good time to dethatch, power rake or core aerate your lawn; turf will need a good 6-8 weeks to recover from these procedures so be sure to do it early in the month. And Labor Day weekend is good time for an early fall fertilizing, if you don’t mulch and leave your clippings on the lawn.
If you cannot tolerate dandelions September is the best time of the year to treat them chemically but early October will work too. Dandelions are perennial weeds and fall is a time of year they are making carbohydrates and transporting them to their roots for the dormant period. If they are sprayed now, they will also translocate the pesticide to their root system and kill the roots – so fewer dandelions next year. That does not mean that new seeds won’t germinate next spring, but at least you will be a little ahead of the game.
Trees and shrubs: Water is also critical for trees and shrubs as they are preparing to enter dormancy. They require 2” of water per week, especially for trees that are younger than 5 years. Once again, high temperatures will contribute to soil moisture evaporation so they may require even more water if we experience hotter than usual weather. Remember to water as far out from the tree as the canopy, as the roots grow that far out from the trunk. (You may already be doing that when watering your lawn.) Continue to water your trees and shrubs until the ground freezes, especially evergreens as they need plenty of moisture to retain their green needles through the winter. Fall is also a great time to plant new trees and shrubs because the cooler temperatures put less stress on them and they are able to develop their root system and become established quicker. If you do plant a new tree or shrub, be sure to mulch over the root system, but not touching the trunk of the tree.
Flowers: Deadheading your annuals will make them continue to bloom until frost, but it is important to deadhead your perennials as well. This will conserve plant energy for next year rather than being used for seed production. It is ok to cut back any yellow or brown foliage on perennials but leave the green so it can continue to produce carbohydrates to store in the roots for next year. Now is a good time to divide and transplant perennials, as well as to plant new ones. The added bonus to fall planting is that many of the garden centers will have perennials on sale. Transplanted and newly planted perennials will need 3 to 4 weeks of mild growing conditions to get established and ready for dormancy so be sure to plant by the end of September.
We may be weary of yard work right now but attention to your yard and garden in the fall will yield big rewards next spring. There will be more tips for the fall in next month’s column.