When recommending lawn fertilization, I have to consider several factors.
Where is the lawn located (What Climate Zone)?
What kind of grass is the lawn made of?
Which type of fertilizer will you use?
Is it a new or existing lawn?
These factors determine what nutrients will be needed and when they will need to be applied.
What is your Climate Zone?
The weather in your area affects your timing. We often refer to the USDA Climate Zone Map to estimate when the weather will be suitable for growing in your location. The seasons officially change on a certain date and time, but growing seasons vary greatly within the Unites States. Your local Zone is good to know, because many plants are rated per zone, as to their cold and heat tolerance. You will see, “hardy to Zone 6 through 9.” This will mean that a plant can thrive in the typical temperatures of that area. If you live north of zone 6, it probably will get too cold for that plant, and when you live south of Zone 9, it will likely be too hot for that plant.
Aren’t all grasses the same?
Grass that goes dormant in the winter is called Warm
Seasoned Grass. The ability to go dormant when it would otherwise be too cold
for it to survive, makes it possible for many of us to have a lush, spreading
grass like Bermuda, Zoysia, Centipede or St. Augustine grass lawn. Feeding a
dormant lawn is not necessary. Wait for these lawns to green up before applying
Fescue, Rye and Kentucky Bluegrass lawns are evergreen and require feeding all year long. These are called Cool Season Grasses. In colder climates, mowing might not be necessary in the winter, but the grass will need feeding during the winter to help avoid yellowing.
Kentucky Bluegrass Lawn:
How often should I apply Fertilizer?
The type of fertilizer that you choose will determine how often the lawn will need feeding.
Liquid fertilizer is readily available and is used up more quickly because of it. Granular fertilizer, like 10-10-10, is also fast acting, therefore it is used up quickly as well.
Liquid fertilizers are used up in about 30 days, so should be applied monthly to an actively growing lawn.
All Purpose granular (10-10-10 for example) fertilizer gets
its nitrogen from ammoniacal sources (ammonia), and this nitrogen is quickly
released and dispersed. This fast action can lead to leaf burn and loses its
potency after about a month.
Liquid and All-Purpose fertilizers need to be applied every month of the growing season.
Premium lawn fertilizer gets
its nitrogen from more stable sources, like urea. Commercial manufacturers
sometimes coat their nitrogen with polymers to slow down the delivery of
nitrogen to the grass, so that it will feed for a longer period of time. The
total amount of nitrogen will be greater, and will release more slowly, over a
three-month period of time.
This is why you should apply premium lawn food every three months, all year long if you have cool season grass. You should avoid fertilizing warm season grass while they are dormant.
Special consideration when starting a new lawn
Phosphorus, the middle number on the bag, is needed when applying new seed, or when you are laying new sod. Phosphorus stimulates new root growth and should be applied along with the seed, or over the newly laid sod. Starter Fertilizer contains this additional phosphorus, so apply Starter one time, when you apply the seed or sod.
Phosphorus is not needed on established lawns, besides, phosphorus will remain in the soil for up to a year. This is why maintenance fertilizers will sometimes have zero as the middle number on the bag.
When your lawn stays green all year long, feed it every
season with a premium granular lawn fertilizer. If your lawn becomes dormant in
winter, apply fertilizer after it becomes about half green in the spring, and
then again after three months has passed.
If you choose to spray your lawn with liquid lawn food, repeat the application every month, while it is green. There is no need to feed a dormant lawn.
Until next time, I’ll see you in the aisles!