When is the best time to fertilize my lawn?
Fall is the best time of year to fertilize Colorado’s bluegrass lawns. Promotions about “lawn winterization” may sound mysterious, but there’s nothing magical about it. Simply fertilize with nitrogen sometime during late September to early November at lower altitudes, and earlier in the mountains.
Why is fertilizing in the fall the best option?
The benefits of fall fertilizing include a healthier turf before winter, a healthier root system, and stimulating a turf that greens up earlier in the spring without excessive top growth. Fall fertilization produces dense, green spring lawns without the mowing chores that come with spring fertilization. It should be a part of every good lawn care program.
What is the best way to fertilize my lawn?
Follow the application instructions on the fertilizer carefully and remember that turf must be green when nitrogen is applied. Also, make sure that the 
soil is moist so the nitrogen will dissolve easily. If not, irrigate and wait a day before fertilizing. Fertilizer applied to very dry, cold soil or to dormant turf won’t be used efficiently.
Are any chemicals in fertilizer bad for grass?
While nitrogen is the most important nutrient, there is no harm if fertilizers also contain some phosphorous or potassium.
For more information, see the following Colorado State University Extension fact sheet(s).
For more information, see the following Planttalk Colorado™ script(s).
- Fall Lawn Fertilization: During Drought
- Organic vs. Manufactured Fertilizers
- Phosphate Fertilizers and Water Pollution
