By Paul James
The window between the end of summer and the beginning of fall is the perfect time to fertilize deciduous plants and turf grasses. And the reason is simple: Providing nutrients that have been depleted during the growing season will enable plants to enter the winter months with the food reserves they need to stay healthy and begin robust growth in spring.
In fact, if you can only afford to fertilize once a year, late summer to early fall (as in now through the end of September) is the best time. Focus on deciduous trees and shrubs, perennials, and turf grasses, including warm-season varieties such as Bermuda and zoysia as well as their cool-season counterparts such as fescue and rye.
What you don’t want to fertilize now are evergreens, including azaleas, boxwoods, hollies, photinias, pines, spruces, cedars, junipers and so on. Both broad- and needle-leaved evergreens should be fertilized in early April through the first of July, but no later. Fertilizing this time of year will stimulate new growth that may not have a chance to harden off before freezing temperatures arrive, and that new growth can easily be damaged.
The choices among fertilizers are so vast and varied that it’s hard to make a specific recommendation. But if you stick with well established name brands – Espoma, Scotts, and Milorganite, for example – you really can’t go wrong. Synthetic fertilizers such as those made by Scotts are extremely water soluble, which basically means the nutrients dissolve quickly and produce rapid results. The nutrients in natural fertilizers made by Espoma and Milorganite are not very water soluble, so it may take a week to ten days to see results. However, the results are typically longer lasting.
For at least 30 years, I’ve used nothing but Milorganite on my lawns and gardens. Strictly speaking, it’s not organic, but it is all natural. It’s made from biomass (fancy word for “poop”) from the City of Milwaukee, and it’s one of the greatest and most successful recycled products in horticulture history. Milorganite is a slow-release fertilizer with an analysis of 5-4-0 plus 4% iron (an overlooked element that helps plants green up). It’s also non-burning, which basically means you can sling it on anything that grows (except evergreens this time of year).