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NPK Ratio

flower garden

The N-P-K ratio is the percentage by volume of nitrogen (chemical symbol N), phosphorus (P), and potassium (K) in fertilizer. A 16-16-16 fertilizer, for example, contains 16% nitrogen, 16% phosphorus, and 16% potassium.

NPK ratio
NPK ratio

How is NPK Calculated?

To calculate the pounds of nitrogen in a bag of fertilizer, multiply the weight of the bag by the percent nitrogen (this is the first number in the N-P-K designation on the front of the bag). Then divide the pounds of nitrogen by the area the bag states it will cover to get the pounds of nitrogen per 1,000 sq. ft.

Roles of NPK

The first number of the ratio indicates the amount of nitrogen in the fertilizer. Nitrogen serves a few different roles but its primary benefit to grass is to help produce lush, green leaves. The second element is phosphorus, which is focused on more of the downward growth and fuels important developments such as root growth. The final nutrient represented in the ratio is potassium. This particular nutrient focuses more on resistance. If you already have an established lawn that’s starting to suffer from stress or diseases then the application of potassium is crucial to the health of the grass.

n-p-k
n-p-k

What’s the Best Ratio?

The NPK ratio represents is the percentage of nitrogen (N), phosphorus (P), and potassium (K) in the fertilizer. So how do you what’s best for what ratio? Here are some basic rules to follow. If you are starting a new lawn then get lawn fertilizer that has a higher percentage of phosphorus and potassium. At this stage, it’s important to focus on root development and disease resistance.

If you are installing a new layer of sod then apply a similar ratio to what you would use for new lawns. Although new sod does have established grass, the roots themselves have been shaved off so it is vital to up the amount of phosphorus in the soil for root development purposes.

Finally, if you are well into the gardening season and have an established lawn then focus on using a fertilizer that has a higher composition of nitrogen. Before Using Lawn Fertilizer perform a test to determine the amount of nutrients that already exist in the soil. This can be done on your own through the use of NPK soil test kit.

Partial Source: http://www.jgilorganic.com/npk-lawn-care/

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Soil management

<img align="right" alt="Soil-Plant Nutrient Cycle - Source: U.S. Geological Survey." class="caption" src="/images/stories/nature/plants.png" title="Soil-Plant Nutrient Cycle - Source: U.S. Geological Survey." /></p> <p>     <span style="color: rgb(0, 119, 0); font-family: Georgia, 'Times New Roman', serif; letter-spacing: 1px;">Essential Nutrients</span></p> <p style="color: rgb(0, 0, 0); font-family: Arial, Helvetica, sans-serif; line-height: 26px;">     There are 15 essential elements that plants must have in order to grow properly.</p> <p style="color: rgb(0, 0, 0); font-family: Arial, Helvetica, sans-serif; line-height: 26px;">     The primary nutrients are&nbsp;<strong style="">nitrogen, phosphorus</strong>&nbsp;and&nbsp;<strong style="">potassium.</strong></p> <p style="color: rgb(0, 0, 0); font-family: Arial, Helvetica, sans-serif; line-height: 26px;">     <span style="color: rgb(255, 102, 0); font-family: Georgia, 'Times New Roman', serif; letter-spacing: 1px;">18 Essential Nutrients</span></p> <ul style="color: rgb(0, 0, 0); font-family: Arial, Helvetica, sans-serif; line-height: 26px;">   <li>        Nutrient elements obtained from atmosphere through photosynthesis       <ul>            <li>                Hydrogen</li>           <li>                Carbon</li>             <li>                Oxygen</li>         </ul>   </li> </ul> <p>     &nbsp;</p>  <!--more-->  <ul style="color: rgb(0, 0, 0); font-family: Arial, Helvetica, sans-serif; line-height: 26px;">    <li>        Nutrient elements obtained from the soil        <ul>            <li>                Nitrogen</li>           <li>                Phosphorus</li>             <li>                Potassium</li>          <li>                Sulfur</li>             <li>                Magnesium</li>          <li>                Calcium</li>            <li>                Iron</li>           <li>                Boron</li>          <li>                Manganese</li>          <li>                Zinc</li>           <li>                Molybdenum</li>             <li>                Copper</li>         </ul>   </li> </ul> <p>     <span style="color: rgb(0, 0, 0); font-family: Arial, Helvetica, sans-serif; line-height: 26px;">Out of the 15 essential elements that come from the soil, we deal with only the 12 that are generally managed by the growers. These 12 elements are &lsquo;mineral nutrients&rsquo; and are obtained from the soil. We further divide mineral nutrients into 3 groups: primary, intermediate, and micronutrients. Our presentation will exclude cobalt, chlorine, and nickel from our discussion on the management of essential mineral nutrients, though are included by many as essential nutrients.</span></p> <ul style="color: rgb(0, 0, 0); font-family: Arial, Helvetica, sans-serif; line-height: 26px;">  <li>        The primary nutrients are&nbsp;<strong>nitrogen, phosphorus</strong>&nbsp;and&nbsp;<strong>potassium</strong>. You may be most familiar with these three nutrients because they are required in larger quantities than other nutrients. These three elements form the basis of the N-P-K label on commercial fertilizer bags. As a result, the management of these nutrients is very important. However, the primary nutrients are no more important than the other essential elements since&nbsp;<em>all</em>&nbsp;essential elements are required for plant growth. Remember that the &lsquo;<strong><em>Law of the Minimum&rsquo;</em></strong>&nbsp;tells us that if deficient, any essential nutrient can become the controlling force in crop yield.</li>     <li>        The intermediate nutrients are&nbsp;<strong>sulfur, magnesium</strong>, and&nbsp;<strong>calcium</strong>. Together, primary and intermediate nutrients are referred to as macronutrients. Macronutrients are expressed as a certain percentage (%) of the total plant uptake. Although sulfur, magnesium, and calcium are called intermediate, these elements are not necessarily needed by plants in smaller quantities. In fact, phosphorus is required in the same amount as the intermediate nutrients, despite being a primary nutrient. Phosphorus is referred to as a primary nutrient because of the high frequency of soils that are deficient of this nutrient, rather than the amount of phosphorus that plants actually use for growth.</li>   <li>        The remaining essential elements are the micronutrients and are required in very small quantities. In comparison with macronutrients, the uptake of micronutrients is expressed in parts per million (ppm, where 10,000 ppm = 1.0%), rather than on a percentage basis. Again, this does not infer that micronutrients are of lesser importance. If any micronutrient is deficient, the growth of the entire plant will not reach maximum yield (<strong><em>Law of the Minimum</em></strong>).</li> </ul> <p style="color: rgb(0, 0, 0); font-family: Arial, Helvetica, sans-serif; line-height: 26px;">   Since the soil provides most essential nutrients, it is crucial that we understand the soil processes that determine the availability of each essential nutrient for plant uptake.</p> <p style="color: rgb(0, 0, 0); font-family: Arial, Helvetica, sans-serif; line-height: 26px;">   <span style="font-size:8px;"><span style="font-family: arial, helvetica, sans-serif;">Source:&nbsp;<a href="https://web.archive.org/web/20181029062821/https://www.ctahr.hawaii.edu/mauisoil/c_nutrients.aspx" style="font-family: Arial, Verdana, sans-serif;" target="_blank" rel="noopener">http://www.ctahr.hawaii.edu/mauisoil/c_nutrients.aspx</a></span></span></p> <p>    <img align="right" alt="fertilizer" class="caption" src="/images/stories/nature/npk_plants.jpg" title="fertilizer" /></p> <h3 style="color: rgb(0, 0, 0); font-family: Arial, Helvetica, sans-serif;">  <span style="font-size:16px;"><span style="font-family: arial, helvetica, sans-serif;">Choosing fertilizers</span></span></h3> <p style="padding-right: 220px; color: rgb(0, 0, 0); font-family: Arial, Helvetica, sans-serif; font-size: 14px;">   <span style="font-size:12px;"><span style="font-family: arial, helvetica, sans-serif;">Fertilizers provide essential plant nutrients including those listed below.</span></span></p> <p style="padding-right: 220px; color: rgb(0, 0, 0); font-family: Arial, Helvetica, sans-serif; font-size: 14px;">     <span style="font-size:12px;"><span style="font-family: arial, helvetica, sans-serif;">Nitrogen (N)&nbsp;promotes strong leaf growth. Buy slow-release nitrogen products called insoluble nitrogen. This is best for the plant; it assures a slower, steady supply of nitrogen</span></span></p> <p style="padding-right: 220px; color: rgb(0, 0, 0); font-family: Arial, Helvetica, sans-serif; font-size: 14px;">     <span style="font-size:12px;"><span style="font-family: arial, helvetica, sans-serif;">Phosphorus (P)&nbsp;helps roots, flowers, seeds and fruits grow and develop.</span></span></p> <p style="padding-right: 220px; color: rgb(0, 0, 0); font-family: Arial, Helvetica, sans-serif; font-size: 14px;">    <span style="font-size:12px;"><span style="font-family: arial, helvetica, sans-serif;">Potassium (K)&nbsp;or Potash, is critical for overall plant health.</span></span></p> <p style="padding-right: 220px; color: rgb(0, 0, 0); font-family: Arial, Helvetica, sans-serif; font-size: 14px;">     <span style="font-size:12px;"><span style="font-family: arial, helvetica, sans-serif;">Secondary nutrients&nbsp;like calcium, sulfur and zinc foster strong stems and overall plant health.</span></span></p> <p style="padding-right: 220px; color: rgb(0, 0, 0); font-family: Arial, Helvetica, sans-serif; font-size: 14px;">    <span style="font-size:12px;"><span style="font-family: arial, helvetica, sans-serif;">Micronutrients&nbsp;such as copper and zinc contribute to plant health.</span></span></p> <p style="padding-right: 220px; color: rgb(0, 0, 0); font-family: Arial, Helvetica, sans-serif; font-size: 14px;">     <span style="font-size:12px;"><span style="font-family: arial, helvetica, sans-serif;">More is not better.</span></span></p> <p style="padding-right: 220px; color: rgb(0, 0, 0); font-family: Arial, Helvetica, sans-serif; font-size: 14px;">     <span style="font-size:12px;"><span style="font-family: arial, helvetica, sans-serif;">Too much fertilizer causes plant stress, and pest and disease problems. Fertilizers can run off into local waterways, polluting them.</span></span></p> <p style="padding-right: 220px; color: rgb(0, 0, 0); font-family: Arial, Helvetica, sans-serif; font-size: 14px;">   <span style="font-size:12px;"><span style="font-family: arial, helvetica, sans-serif;">Balance is the key.&nbsp;Don&rsquo;t fertilize at all, unless plant&#39;s or a soil test show a need. Only apply amounts recommended on the label.</span></span>