Just like people and animals need a variety of vitamins and minerals to be healthy, plants need a variety of nutrients to grow strong.
There are 18 recognized plant food nutrients divided into several categories.
Macro nutrients are considered essential for all plant life. All plants require these six nutrients.
Carbon, Oxygen and Hydrogen are easily obtained from the environment and are not typically included in fertilizers.
Nitrogen, Phosphorus, and Potassium are the standard nutrients included in the majority of fertilizers. They are so standard that they are considered the "Grade" or "NPK."
Calcium, Magnesium, and Sulfur are the next most important nutrients for plant growth.
Boron, Chlorine, Cobalt, Copper, Iron, Manganese, Molybdenum, Nickel, Sodium, and Zinc are also recognized as generally beneficial nutrients but their usefulness depends on the plant's individual needs. Micro-nutrients fill very specific plant needs and so a little bit goes a long way.
Now we know that all plants need nutrients. But how much do they need? Depending on the plant, the soil, the climate, the season, a plant's needs fluctuate.
Fertilizers are not one-size-fits-all. But there are fertilizers that can fit most. If you'll recall, all plants need macro-nutrients. So you don't have to know everything about your plant's needs to know that it's going to need Nitrogen, Phosphorus, and Potassium.
Each nutrient helps your plant in several ways. But an easy way to remember the general uses of NPK is the saying "Up, Down, and All Around."
While Nitrogen also helps with root growth, it is a major factor in the production of green leaves and stems (Up). This is why turf fertilizers have high Nitrogen content, so they can get a nice thick green lawn.
Phosphorus helps a with flower development but is primarily involved in root growth (Down). Phosphorus is a mineral that is readily available in the soil of some locations, and that is why you see some fertilizers with less phosphorus than other nutrients.
Potassium can also help with root growth but is mostly associated with a healthy immune system (All Around). Plants use potassium to fight pests, diseases, and handle stressful environments like drought, heat, or sudden temperature changes.
The format of the fertilizer is another factor.
Water soluble fertilizers dissolve in water and can be used immediately by the plant. So if you have a plant that has a specific need at the moment, you'd want a water soluble fertilizer. The downside to water soluble fertilizers is that what isn't absorbed by the plant's roots either sinks out of range or is converted by microbes into forms that the plant can't use. So you need to reapply water soluble fertilizers more often.
Controlled Release Fertilizers are solid fertilizers that have a coating that slowly breaks down, releasing a small amount of nutrients over a long period of time. The benefit is that you can leave it and forget it (depending on the longevity of the fertilizer) and know that your plants will have a constant source of plant food. The downside is that if you have a plant that has a specific need at the moment, it will take time for it to obtain the nutrients it needs.
Whether or not you know your garden's specific nutrient needs, we have fertilizer for you.
If you have no idea where to start, our Bubble series is a good place to start. The water soluble fertilizers provide general nutrition in a format where your plant takes the nutrients it needs and any excess decomposes harmlessly. Whether you're growing edible crops, beautiful flowers, or anything else, we have a formula for you. And all of our products pair well with our Nutri Bubble with supplemental nutrients. Visit our product page to learn more.
If feeding your plants every week sounds like too much bother, we have Dr. Joe HI-COTE, which only needs to be applied once every 3-4 months while the plant is actively growing and provides a balanced NPK with key micro-nutrients. Visit our product page to learn more.
If you have a nursery or greenhouse and need higher volumes, we have both water soluble and controlled release fertilizers in 25 and 50 lb bags in a variety of longevities. Visit our product page to learn more.