Fertilization Instructions
Whether it's a tree, shrub, annual bed, perennial garden, vegetable garden or the lawn, timely fertilization with the right fertilizer is key for maintaining overall health and vigor of plants.
Choose from a category below to find fertilization instructions:
TIP: You can also find specific fertilization instruction for every plant featured on the website in each and every Plant File. Click here to go to the Plant File for Crape Myrtle 'Dynamite'. You'll find the feeding instructions under a tab just to the right of the plant photo.
To find a particular plant visit the Plant Files
The Basics of Fertilizer
Determining what fertilizer to use for various purposes in the landscape can be an overwhelming task. Which formulation do you need for your particular situation? Should you get the bag of 10-10-10 or the bag of 16-4-8, or should I look for something organic?
And what do those numbers mean anyway?
It may seem a little confusing, but you can figure it out. When selecting a fertilizer, the first question to answer is, "What analysis do I need?" The analysis is the three large numbers you see on every fertilizer label, such as 12-6-6 or 10-10-10 or 6-2-0. These numbers represent the percentage (by weight) of the three major nutrients required for healthy plant growth. These three major elements are always in the same order: Nitrogen-Phosphorus-Potassium (N-P-K). Each of these nutrients affects plant growth differently.
Nitrogen (The First Number in Fertilizer)
The first number represents nitrogen. Nitrogen provides plants with the ability to produce more chlorophyll, which in turn sponsors more rapid growth to the part of a plant that is above the ground: the foliage. With each additional nitrogen application, plants should grow taller and greener. Typically, fertilizers that are high in nitrogen content are not recommended for use on most ornamental plants (shrubs and trees), while lawn fertilizers may contain high amounts of nitrogen; particularly in Spring feeds. A well-balanced shrub and tree fertilizer might contain 10 to 15 perecent nitrogen, such as 12-6-6, which contains 12 percent nitrogen, while a Spring Feed lawn fertilizer might contain 20 to 30 percent nitrogen.
Phosphorus (The Second Number in Fertilizer)
The second number represents phosphorus. Phosphorus aids in root development and therefore can help to increase bloom size and bloom production. A fertilizer high in phosphorus content can be used when planting new trees and shrubs, to help them "root in" more quickly. When planting a new lawn, you might choose a "Starter" fertilizer that has a high content of phosphorus. Once a plant has become more established, a well-balanced shrub and tree fertilizer such as 12-6-6, or something similar should be sufficient for most shrubs. If you have blooming plants that haven't been blooming so well, you might consider using Triple Super Phosphate (0-45-0) to boost root growth and increase bloom production.
Potassium (The Third Number in Fertilizer)
The third number represents potassium. Potassium has many functions: It guards the plant against diseases and aids in drought protection and cold tolerance. It also serves a role in improving root development, strengthens stems, and helps in the process of photosynthesis.
Other Important Information About Fertilizer
You might have noticed that all the numbers in the fertilizer analysis don't add up to 100 percent. That's because there are fillers often added to the mix to help apply the nutrients over a larger area.
The best fertilizers will often contain what is called a "micro-nutrient package". This package may contain other nutrients that ornamental plants or lawn grasses appreciate, such as: iron, sulphur, manganese, zinc and others.
Experienced gardeners, nurseryman and professional landscapers may recognize a plant's need for fertilizer, or the need for a particular nutrient, by simply looking at the foliage. For example, if the foliage of a plant is turning light green or yellow, this might indicate a nitrogen or iron deficiency, or perhaps there's too much moisture around the roots. Similarly, purple foliage (on an otherwise green plant) might be a sign of phosphorus deficiency.
The only sure way to determine what fertilizer or nutrients a plant needs is through having a soil test done. Most states, and many counties offer soil tests through their Cooperative Extension Service at no charge (or for a small fee). A soil test will indicate what nutrients are needed, and ensures that the correct amount and type of fertilizer will be used on your plants or lawn.
In the absence of a soil test, always consult with your local independent nurseryman or a reputable professional landscaper as to what fertlizer might be needed for the plants, trees and grass in your landscape.