Written by: Doug Chilton, Outside Sales, Hydro-Scape

Your lawn needs proper nourishment, in addition to what it gets from the soil, in order to thrive. Nourishment in the form of fertilizer helps your lawn stay lush, green and healthy. There are so many products on the market and opinions on fertilizing; I wanted to break it all down for you into an easy one-stop guide.

Fertilizer Numbers: the Winning Combination

Walking into one of our branches and past a number of fertilizer pallets can be an overwhelming task. White bags with multi-colored buzz words on them like “Supreme,” “Evergreen,” “Super,” and “Plus.” They all promise to turn your lawn into the envy of the neighborhood. How do you decide?

First, ignore the flashy names and focus on the fertilizer numbers or N-P-K ratios. These three numbers – and this guide – will help assist you to make the right decision.

The three numbers tell you the percentage of Nitrogen, Phosphorous and K, which is potassium or potash. These are the guaranteed analysis, in each bag, of the nutrients your lawn needs. If a bag says “13-5-8” Evergreen, it contains 13% nitrogen, 5% phosphorous and 8% potassium. No, that doesn’t equal 100%. The remaining percentage amount is made up of fillers and other food elements and micronutrients to help you get more of an even application.

Why Are These Numbers Important?

Your lawn requires different nutrient levels depending on its condition and what season we are in. Not only different levels but different types depending on how slow or fast the feeding is needed. Soil temperatures play a big part on how fast the lawn can process the nutrients. Just like teenagers can eat you out of house and home because they’re growing, your lawn has stages, too. Each stage or condition has its own unique set of nutrient needs.

New Lawns

New lawns need extra phosphorous to help them grow strong root systems. High nitrogen fertilizer isn’t appropriate here, as the new roots aren’t ready to support a lot of above-ground growth. A mix that is low N, high P and high K like 6-20-20 is perfect, the focus is on phosphorous, which:

  • Stimulates early root formation and growth
  • Helps plants mature
  • Promotes development of blooming and seed development
  • Improves the strength and stamina of the plant
  • Creates a root filter system in the soil making the roots more efficient

Established Lawns

These lawns need nitrogen. Different types are needed depending on what season you are in or how quickly you need the lawn to become green.


  • Key ingredient for a dark green color
  • Vital element in the formation and function of chlorophyll
  • Promotes rapid growth and recovery after mowing

Stressed Lawns

When lawns are dealing with extreme heat or getting ready for winter, they often become stressed. The best thing for stressed lawns is potassium. You want big N, small P & medium-to-high K. The potassium:

  • Helps restore vigor & health to deal with changing weather
  • Increase disease resistance
  • Aids the lawn in manufacturing food from the soil & fertilizer
  • Prevents slow growth and weak stems

Types of Fertilizer

There are synthetics, organics, water-soluble and granular varieties, as well as quick- and slow-release.


Applied with a hose end sprayer or through a fertilizer injector. Great when used with a drip or low volume spray system. Primarily used in shrub and ornamental beds.


These are applied dry and are either quick- or slow-release. This type is applied with a shaker or a spreader and gives you the best chance for even applications.


These can be plant-based like hums or compost. Animal-based like manure, fish emulsion, blood, and bone meal. Using a hybrid blend where the filers are made from organic materials is an available option for lawns.

Quick Release Granulars

Also known as water-soluble nitrogen or WSN, these fertilizers feed your plants immediately. They last for three to four weeks, depending on rainfall and temperature. Quick green but also a flush of growth.

Slow-Release Granulars

These are water-insoluble or WIN and come coated in either sulfur or polymer. The sulfur-coated versions provide eight weeks of nutrients and the polymer-coated fertilizers give around twelve weeks of food. This also depends on rainfall and temperature.

We recommend slow-release granulars. This saves you time and money with less applications while providing the right nutrients to your lawn. There is also less risk of blade burn with this type.

Start the New Year on the right schedule

To keep your lawn healthy throughout the year lawns need regular fertilization to keep them going strong. Our recommended schedule is:

  • First application: January or February, When the soil temperature is reliably at 55F. Quick greening or a nitrate nitrogen to help jump start your lawn. Nitra King 19-4-4 with its 4% nitrate nitrogen will promote a quick green
  • Second application: around spring time to keep your grass going, a nice slow release or coated nitrogen. You get a longer feed time with less applications. Super Turf 25-5-5. High in nitrogen without the quick flush of growth.
  • Third application: 12 to 14 weeks later. Evergreen 18-5- 0 will keep the lawn  dark green and looking healthy throughout the summer
  • Fourth app. 8 to 10 weeks later something more balanced as we prepare for the soil to start cooling down. 16-16-16 Endure is a slow release with all the nutrients your lawn will need heading into winter.

Tip: Make sure you water in the fertilizer thoroughly. Fertilizing after a rain helps but don’t rely that your lawn is wet enough to keep the fertilizer from burning. Remember to sweep any excess prills on to your lawn before watering in. Some fertilizers have extra elements and minerals in them. Some of these could be iron and it will stain your concrete.

Applying Fertilizer to Your Lawn

First off, pay attention to the application rate on the bag! More is not better, unless you want to mow your lawn twice a week. Check the spreader calibration chart on the bag. Most brands will have a number of different manufacture spreader setting and the number they use for the rate. Then, fertilize the perimeter of your lawn and do the middle in one direction only. When you’re done, do it again in a perpendicular path. You’ll get the most even application this way.

Hydro-Scape is here to help

I hope that this information takes away any of your confusion about your lawn’s fertilizer requirements. Feel free to stop by any of our 17 branch locations if you still have any questions or concerns. We have experienced customer service representatives that can help you make the correct fertilizer choices for your lawn and landscape needs that will leave you with that beautiful green and healthy landscape you are looking for.