Q. When is it time to start fertilizing lawns again?
A. It depends on whether the lawn is fescue, only Bermudagrass or Bermudagrass overseeded in Fall to maintain green winter color. Fescue lawns and overseeded Bermudagrass lawns are fertilized the same during winter months.
Fescue and overseeded Bermudagrass should have been fertilized last Thanksgiving to maintain dark green color through winter. If this fertilizer application was missed and temperatures get cold, the lawn can turn brown when it gets very cold or just light green if it does not.
The next fertilizer application to fescue lawns would be when air temperatures enter the 60s. Fertilize Bermudagrass that was not overseeded when temperatures enter the 80s.
Established lawns require fertilizers containing high nitrogen, and occasionally an application of iron, for dark green color. However, they will perform best if this fertilizer contains also low levels of phosphorus and moderate to high levels of potassium.
For this reason, fertilizers similar to 21-7-14 or 10-5-10 are frequently recommended for lawns. Some people use only high nitrogen fertilizer such as 21-0-0 and omit phosphorus and potassium.
I think this is a mistake and a good lawn fertilizer should be applied at least once during the growing season. Instead, experiment and try fertilizing with only half the amount of fertilizer recommended on the bag. This is all that is usually needed if you are not bagging lawn clippings but mulching them back into the lawn using the mower.