When you wish to have a green and healthy lawn, you have to be prepared to take regular care of it at least half of the year. In this article, you will find answers to when to fertilize the lawn and to 6 other relevant questions about fertilizing.


Why a lawn needs fertilizer?

A lawn needs Nitrogen for growing, and staying green and healthy so it’s more resistant for diseases and pests. Fertilizing will keep your lawn dense and reduce the opportunities for weeds to grow. Lack of nutrients will turn your lawn yellow and sparse but too frequently repeated fertilizing makes your lawn grow like crazy and it needs constant mowing. The secret is to fertilize it just enough to keep it green.

Does my lawn need it?

First, you have to find out with soil test what nutrients your soil lacks of, or in fact, if it needs fertilizing at all. Don’t waste your money fertilizing it blindfolded just because your neighbor is doing it.

How much do I need it?

Fertilizer coverage area is given on the product label by square feet. Measuring and calculating your lawn area is a must to do before you head for buying fertilizer.

How do I choose the right fertilizer?

When you decide to go with commercial fertilizer, there’s going to be multiple brands and products available. Picking up the right one for you, depends on many factors.

It needs to have the right amount of nutrients for the grass to grow. The product label has a 3-digit fertilizer grade of the main nutrients N-P-K, for example, 29-0-5. Numbers will tell you how big percentage of the weight of the product has each nutrient.  Alphabets stand for following;

  • N for Nitrogen; Nourishes plants green leaves and provide growth.
  • P for Phosphorus; Feeds a plants fruit or flower.
  • K for Potassium; Helps a plant to grow roots and endure through stresses.

You choose the right amount of nutrients for your lawn depending on the season.

Spring and summer

If your lawn is over 6 months old you choose a fertilizer which is;

  • High on Nitrogen, because it is the most important nutrient for matured growing grass.
  • With 0 Phosphorus, because full-grown grass doesn’t have any flower or fruit. Unused Phosphorus will runoff through the soil to little streams and eventually to surrounding waters and there feeding algae and destroying nature balance.
  • A small amount of Potassium, because it enables grass to grow wide and deep root system and help it survive better from drought and survive with less watering.


When you live in the cooler regions your lawn needs fertilizer which is often called winterizer. It’s with a bit more Potassium, so grass can better prepare for the stressful change to winter and it will help your lawn to turn green faster next spring. For cool-season grasses, this is the most important fertilizing of the year.

Young lawn

If your lawn is just planted or is under 6 months old it needs a starter fertilizer. This is with more balanced nutrients and higher in Phosphorus what grass needs when it’s maturing from a seedling. At the side of a starter fertilizer product, you’re looking for numbers like 18-24-6. Do not use this product for the already matured lawn because it can not use all the Phosphorus and will only harm surroundings.


Should I take synthetic or organic?

Cons of quick release synthetic fertilizer;

  • Adding too much will burn or even kill your lawn.
  • Requires continuous use to keep grass growing.
  • Doesn’t support the natural health of the soil.
  • Easier runoffs to surrounding waters.
  • Dangerous for the health of humans and animals.


  • Cheaper
  • Easy and fast to spread
  • If weed control is included, there’s no weeding required.

Cons of slow-release organic fertilizer;

  • Higher price
  • Requires some amount of work hours for weeding but is totally doable for a homeowner when you use also organic weed suppressant.
  • Low-quality organic fertilizer which doesn’t support soil natural health, will runoff to surrounding waters as easily as synthetic.


  • Will release nutrients at a steady pace. Can’t burn or kill your lawn.
  • Improves natural health of the soil and with time reduce the need for fertilizer.
  • Safe for the health of humans and animals. Lawn can be used right after applying fertilizer.

What else I can do for my lawn?

Other organic ways to fertilize and support your lawn’s health and microorganism is;


You just simply allow grass clippings to remain on your lawn and let it decompose, with time it return nutrients to the soil. You might need a mulching blade for your mower to cut grass clippings finer and so quicken decomposition. Grasscycling can reduce up 30% need for fertilizing.

Adding compost

Early spring, before the peak of the growing season, apply a thin layer on top of the lawn so that part of the grass blade is still visible.

Plant clover with your grass

Clover brings Nitrogen to your soil and feeds grass. It can also tolerate better drought and reduces the need for watering. It stays short naturally so it helps with mowing. Clover is evergreen even in colder regions and is more resistant against common diseases and pests, also lawn grubs included.

How do I apply it from a bag?

Depending on the product, you can apply fertilizer as liquid solution sprayed with your garden hose end sprayer, granulates with a handheld spreader or with pushing a spreader for bigger loads. Commercial brands usually have their own fertilizer spreaders where the right dosage is already put-up. When you apply any other way, you can find the right dosage only by testing. Start with half of the amount what you calculated for the need for your lawn.

Spread fertilizer with steady marching pace beginning around the edges and then inner part going back and forth with evenly order overlapping distribution pattern slightly with each pass. When you accidentally dump granulates to one spot, you need to spread those evenly with a stiff broom or leaf blower or the lawn will die from those areas because of too high dosage of fertilizer. Remove fertilizer from walkways and prevent it to be transmitted to storm drains or indoors under your shoes.

Green, healthy turf is a joy for the eyes

Here we went through some main points of fertilizing and also how you can keep your grass greener than your neighbor. Remember to keep up with your regular lawn maintenance chores. It can take some time but is so worth it.

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6 thoughts on “When to fertilize the lawn – 7 things to know about fertilizing

  1. I’d definitely go for slow release, simply due to lower health risks associated with it. Not just this, the fact fast-release can kill a lawn or even cause continual growth means more maintenance. While the quality isn’t as good in slow release, I’d personally feel better using it.

    1. Hi Todd!
      Yes you’re right, synthetic fast release fertilizers have a lot of negatives. Going organic way might need a bit more work but eventually, healthy lawn can turn into a real money saver.
      Thank you for sharing a comment and happy gardening!

  2. Dear Mari
    Thank you very much for your fantastic website. It is amazing that you show people where to start and what steps to make towards their amazing, healthy and relaxing hobby – gardening. I hope more people will know about your website and follow your guidance.
    Kind regards,

    1. Hi Andrey!
      Thank you for visiting my site and sharing comments, all feedback is very welcome. I hope I can help as many people as possible to create beautiful landscapes and get also, like you said, great health benefits from gardening.
      All the best and happy gardening,

  3. Healthy lawns get most their nutrients from microbes in the soil that feed on organic matter. When you fertilize with strong synthetic chemicals, the microbes get a burst of nutrients, causing a population bloom that quickly consumes all the organic matter that is stored in the soil.

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