At first glance, a fertilizer label is a confusing listing of numbers and nutrients. Fertilizer companies are required to list the ingredients and the amount of nutrients on every bag. Although it may seem like gibberish at first, learning the basics about these numbers and how they help your plants can lead to a healthier lawn or garden.
N-P-K: What These Numbers Mean
The most prominent numbers on any fertilizer bag are the big three—nitrogen, phosphorus and potassium (N-P-K). These are usually listed in bold print on the front of the bag, although sometimes you will have to look at the back label to find the information. Each of these nutrients are key to plant growth.
Nitrogen (N) is used up quickly by plants, so they need an ongoing source to replenish it as they grow. Nitrogen is mainly used for lush and healthy leaf growth. It is often the highest number on lawn fertilizers, or for fertilizers for foliage plants, such as houseplants or leaf-bearing vegetables like lettuce.
Phosphorus (P) is needed by all plants, because it helps plants successfully convert other nutrients to a usable form. It's often higher for plants that are grown for their flowers because these plants have higher nutrient needs than foliage plants.
Potassium (K) is another essential nutrient. Plants use it to fuel reproduction, so plants grown for flowers or fruit may have higher potassium needs. Potassium also helps plants regulate their water intake, so even nonflowering plants have potassium needs.
The N-P-K number on the bag indicates the percentage of each of these three fertilizers in the mix. So a fertilizer with a listing of 10-10-10 contains 10 percent each of nitrogen, phosphorus, and potassium.
Find the Trace Nutrients
Many plant have requirements that go beyond the three main nutrients. Zinc, magnesium, iron, and copper are just a few than you may find. This information is usually listed in detail on the back of the bag, along with the percentage of each.
You will also find more information on the specific sources and types of the three main nutrients, N-P-K. This comes in handy if your plants need a nutrient from a specific source. Nitrogen, for example, comes in two main varieties. One variety is immediately available upon application, while the other type may take time to fully release into the soil.
If you want an organic fertilizer, you can use the back label to verify that the sources meet the requirement. Organic labeling requirements will ensure that the ingredients meet organic regulations, but some fertilizers are organic even though they don't sport the label. If the ingredient lists contains blood meal, bone meal, potash, and other recognizable words, chances are it's organic. Don't be worried if your organic-labeled fertilizer does list some chemicals in the ingredients list. Just because you can't pronounce it doesn't mean it isn't organic. Instead, look for the "derived from" listing available on most organic fertilizers to verify the sources of the chemicals.
Learning your plants' nutritional needs and figuring your way around a fertilizer label will help your garden grow healthy. Good plant nutrition is a combination of soil quality and proper fertilizing. Talk to a professional like T And N Inc for more information.