I saw a display of fall lawn fertilizer in the store. Is this a good time to fertilize lawns?
September through November is a good time to fertilize your lawn. If you are not irrigating your lawn, wait until fall rain settles in. If your lawn is not as green as you would like it to be, I would fertilize right away. If your lawn looks good now, you could wait awhile. Fertilizing later will give you a better carryover into next spring.
I consider a fall fertilizer application just as important as a spring application. Important things happen in the fall. Fall fertilization keeps grass green through the fall and winter even after new top growth has stopped. The soil is still warm and grass plants make a lot of root growth, even after top growth stops. New roots and stem growth cause turf to thicken. Food produced by the leaves is stored for the winter and next spring. Some of the nitrogen taken up by the roots is used to make amino acids. These stored amino acids are available for new growth early in the spring before soil is warm enough for roots to take up nutrients, so you get earlier green leaf growth.
Fall fertilizer usually contains more potassium, which makes grass more resistant to winter weather. I prefer fertilizer that has some of the nitrogen in slow-release form. Granules are coated so only part of the nitrogen is released each time moisture is received. Read the “guaranteed analysis” label to make sure lawn fertilizer contains other valuable ingredients such as small quantities of iron and other micro-nutrients. Iron turns grass dark green within a day or two.
In addition to fertilizer, I like to apply lime every other year to both lawns and flower and vegetable beds to reduce soil acidity. Fall is a great time to make this application.
Wait until mid-November to fertilize trees and shrubs. By then, top growth has become dormant, but roots can continue to take up fertilizer. Stimulating new growth now will make woody plants more susceptible to winter damage. The little fertilizer they take up from lawn application will not hurt them.