Slow Release Granular Fertilizers Save Time and Last Longer


Granular fertilizer is dry plant food that is formulated to dissolve over a long period of time, providing a steady source of nutrients to your plant without the need for frequent applications. Some types of slow release granular fertilizer are sprinkled on top of the soil, and some are worked into the soil with a small trowel or rake.

Granular fertilizer is can be purchased in twenty pound bags (or in even larger bags if necessary), or it also can be purchased in smaller jars and boxes that are more or less concentrated depending on the specific brand and purpose.

All plant fertilizers are marked with a three-numeral formula on the label that shows at a glance the percentage of each of three major nutrients included in the food. This three-numeral formula is often called the N-P-K formula or the N-P-K ratio.

The ‘N’ in N-P-K stands for nitrogen. Nitrogen feeds the leaves and greenery on the plant. The ‘P’ stands for phosphorus, which encourages strong root growth and helps buds and flowers to form.  The ‘K’ stands for potassium, which is essential to general health and basic functioning of all plants. Each element is assigned a number, and the three numbers are separated by dashes.

The higher the numbers on the label, the more concentrated the granular fertilizer is. For example, a 24-12-10 granular fertilizer is made up of 24% nitrogen, 12% phosphorus, and 10% potassium. The N-P-K numbers show this right on the label. A 24-12-10 formula is fairly concentrated. An 8-5-4 formula is fairly weak.

A high nitrogen granular fertilizer (for instance, the 24-12-10 ratio in the example above) will plump up the plant’s leaves and make the plant grow large quickly. Some specific types of plants (like roses, for example) need a lot of nitrogen to perform their best. Other kinds of plants (like hydrangeas) will not flower well if fed too much nitrogen. Knowing your plant and what kind of food it needs is very important when it comes to choosing the right fertilizer.

A granular fertilizer with a high middle number (for example, 12-24-10) will help to establish a strong root system in a plant, and will foster the development of lots of flower buds and fruit. A 12-24-10 fertilizer is made up of 12% nitrogen, 24% phosphorus, and 10% potassium. A high-phosphorus fertilizer is especially good for trees and shrubs, but it is also a fairly safe choice when you aren’t really certain what kind of fertilizer to buy.

Most all purpose granular fertilizers have a middle number (the phosphorus number) that is roughly twice the first number (nitrogen) and twice the last number (potassium). The lower these three numbers are, the more often you can use the granular fertilizer. So, for instance, you can use an 8-5-4 fertilizer more frequently than a 24-12-10 fertilizer.

For best results, always pay attention to the instructions on the box or bag, and don’t over-feed your plants. More is not necessarily better. Every plant has specific needs and most plants benefit from a high-phosphorus granular fertilizer no matter what their specific needs. Too much nitrogen (the first number) can ‘burn’ some plants, so be careful.

Searching the internet for the different kinds of granular fertilizers available and reading up on the specific kinds of plants you love and their specific needs will help you determine what kind of granular fertilizer is best for you and your garden. Once you understand the numbers and your plant, the rest is easy.

Categories : Fertilizing