NPK Fertilizer

March 20, 2015
  • NPK Fertilizer

NPK, What’s In The Fertilizer Bag?

Choosing the proper fertilizer is an important step in taking care of your lawn. Each fertilizer bag comes with a label, and each fertilizer label has an important series of numbers called the NPK. Knowing how to read a fertilizer label is the key to picking the correct fertilizer.

The three numbers you see on a fertilizer label is the NPK number, which is actually three numbers that represent the key nutrients in the fertilizer.

  1. N, Nitrogen – Nitrogen is especially important for top growth and is responsible for encouraging lush green lawns with healthy leaf growth.
  2. P, Phosphorus – This usually comes in the form of phosphate (P2O5). Phosphorus is responsible for plant energy and facilitates growth while building a good strong root system
  3. K, Potassium – This usually comes in the form of of potash (K2O). Potassium is great for building an all-around stronger plant by making stronger plant cells. This helps your lawn to better withstand the stress of heat, cold, disease, or pests.

Calculating NPK

When looking at your fertilizer label’s NPK number, you will want to pay attention to both the ratio and the analysis. This is done with some simple math.

Let’s say you have a 50 pound bag of fertilizer with an NPK of 10-10-10. This is the fertilizer’s ratio of nitrogen (N) to phosphorus (P) to potassium (K) and is a percentage. In order to find the analysis of exactly how much of each nutrient you are getting, we do some simple math.

50 X 0.10 (the ratio turned into a decimal) = 5.

This means that in this 50 pound bag, you are getting 5 pounds of nitrogen, 5 pounds of phosphate, and 5 pounds of potash. This is a total of 15 pounds of nutrients. You can then divide the 5 by the number of sq. ft. the bag will cover to get your total nutrients per 1000 sq. ft. Example, 5 ÷ 10,000 = .0005 x 1000 = .5lbs  per 1000 sq. ft. of nutrients.

Bigger Is Not Always Better

Alfalfa 3-1-5 LabelA common misconception is that the bigger the numbers on the fertilizer label, the better the fertilizer. In reality, lower numbers are actually healthier for your lawn. High NPK numbers on fertilizer labels mean fertilizer that may lose its nutrient value as its being applied or encourage excess top growth, which puts stress on a plant’s root system and leaves your lawn susceptible to damage and disease. Most fertilizers with any of the NPK numbers higher than 12 may not truly be organic.

Organic vs. Synthetic

Organic fertilizers especially have lower numbers, and tend to be made of healthier components for your lawn. This is important because fertilizer run-off can be damaging to water systems that it comes into contact with if it contains pesticides or excess nitrogen, which can encourage algae growth.

Synthetic/traditional fertilizers contain water-soluble nitrogen that begins working when it comes into contact with soil moisture. This fast-acting quality might sound good but in reality it isn’t as beneficial because within 4 to 6 weeks the fertilizer will be gone and need to be reapplied. In addition, because they are water-soluble it is easier for inorganic fertilizers to leach into ponds and streams. Inorganic fertilizers can also put a strain on your plants, giving them a quick burst of nutrients that may stress them by stimulating too much growth too quickly.

In contrast, organic fertilizers like the ones used by Omaha Organics use a type of nitrogen referred to as Water Insoluble Nitrogen (WIN). WIN is a long-term investment for positive lawn care because it is slower to be released and can benefit your lawn for months after application. It’s also much safer for your lawn, your family, and your pets.

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