But early fertilizing can deplete energy needed for root growth. Wait four to six weeks between applications. Use a slow-release form of nitrogen.
Regular urea is quick-release.
Milorganite, which is recycled sewer sludge cleaned of heavy metals, is a particularly good choice if you skipped the fall fertilization and plan to fertilize in April, says Matt Fagerness of Kansas State University. It's a slow-release fertilizer that also provides organic matter. It is best to avoid them, Fagerness says. In our climate, fertilizer and herbicides need to be applied at different times. The one exception is long-lasting crabgrass preventer that includes fertilizer.