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How to Decide When to Fertilize Your Lawn

Perhaps your lawn isn’t growing as well as you think it should, or maybe it looks a little off. You just moved to a new home and don’t know what your new lawn needs to do its best. Regardless of the reason, you need to figure out when to fertilize a lawn.

Time of Year

How to Decide When to Fertilize Your LawnMany homeowners fertilize their yards up to twice a year, where others put a top dressing of fertilizer on several times a year. How do you decide when to fertilize your lawn? As much as everyone hates this answer, it depends. You’ll need to determine your lawns needs as detailed below, but here are some tips on helping you decide when to fertilize a lawn.

Do you have a fast growing grass, such as Bermuda? Plants that grow quickly take nutrients out of the soil faster. Be careful that you don’t put too much fertilizer on at once, burning the plants. If you’re having to water over a hot summer to keep a fast growing warm season grass growing, you may want to consider using fertigation, a technique that includes fertilizer with irrigation water. In addition to fittings that go on the end of your hose, you can also look at a fertilizer siphon, which pulls fertilizer into irrigation water from a bucket or other container. This is a technique commonly used in greenhouses.

What’s your soil like? Clay and clay loam soils will hold onto nutrients much better than sandy and sandy loam soils, which tend to lose their fertilizer load more quickly. This means that you’ll have to apply fertilizer more frequently in sandy soils.

Does your soil have good organic matter content? If clay is the king of holding nutrients in the non-organic components of soil, organic matter is the emperor, holding nearly ten times the amount of nutrients that even clay does.

Special Circumstances

There are also particular times that you’ll want to provide extra fertilizer to your lawn or may want to hold off entirely for a while. Here are some things to consider:

Have your recently planted your newly researched grass seed? You’ll want to wait six weeks after the seed has germinated to put a dressing of nitrogen on. New plants need to replenish their nitrogen supply, used during growth cycles. Putting it on too soon or in too high a quantity can burn the plants; not putting it on at six weeks of growth keeps the plants from growing as well and establishing as well as you’d like.

Have you had a lot of traffic on your yard? Splitting your normal schedule to give two feedings slightly more than half of a normal one several weeks apart will help your lawn recover without risking runoff issues.

Is your lawn stressed from excess or lack of moisture? In wet conditions, the fertilizer flows away in the rains, not helping your lawn and causing problems with area waterways. During droughts, excess nutrients can keep your lawn from extending roots downwards or can burn the plants because of the lack of moisture to dilute the concentration it is taking up.

Determining its Needs

The best way to determine your lawn’s needs is by performing a proper soil test. Though you can purchase simple to complex soil tests to conduct at home, many homeowners take a soil sample into their county extension office, managed the your state’s land grant university, to have it tested. A soil test conducted by your extension office will include not only soil type and ability to hold nutrients, it will also include recommendations for fertilizing your lawn, what quantities of lime or sulfur required to adjust the pH and even expected crop and fruit tree yields from that particular soil. Your county extension agent can also help give you some ideas on when to fertilize a lawn. There is a small fee paid at the office, typically under $20-$30.

Now that you know what your soil is needing, let’s figure out how much to apply. The three numbers on fertilizer bags refer to the content of nitrogen, phosphorus and potassium as a percentage of the bag’s total weight. A 100# bag of 16-4-8 has 16# nitrogen, 4# phosphorus and 8# potassium, so if you need that mixture to put 10# nitrogen on your lawn, you’ll divide 10#/16# and multiply by 100 for 62.5# of fertilizer.

Now that you know when to fertilize a lawn, read our other articles!


About the author

Mark Kelly

Hi, I'm Mark the owner of Yard Care Gurus. I love to be outside working on my lawn, planning my next project. I created this website to help people like you find the best products for yard care and great advice. Thanks for stopping by!

Johnny McCarron - October 24, 2016

I really like your advice to consider the time of year when you are choosing a fertilizer. Some just don’t work as well as others, and you want to be sure that you are making the correct decision when it comes to your fertilizer. That being said, I’m not too familiar with how to do choose the right fertilizer. Do you have any other tips?

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