p a darker green color. So if you want a dark green lawn, use a lawn fertilizer that’s high in nitrogen – but then expect to mow more often.
The second number in the analysis is the percentage of phosphorus in the mix. For example, a bag of 24-8-4 would contain 8 percent phosphorus. Phosphorous aids in root development and increases flowering ability and bloom size. The fertilizer industry smartly markets high phosphorus fertilizer as “Bloom Booster.” High-phosphorous fertilizer should be used when plants are being established in your garden – when sowing a new lawn or planting a new tree, for instance.
The third number represents the percentage of potassium found in the product. A bag of 24-8-4 has 4 percent potassium in the mix. 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 and helps in the process of photosynthesis. You might consider using a high-potassium fertilizer at the start of winter and summer to protect crops from temperature extremes or when insects and disease have caused damage to your plants.
Now, if you’re a left-brainer, you’ve probably noticed that the sum of the percentages don’t equal 100 percent. That’s because there are other nutrients and filler product in fertilizer mixtures. This filler helps to apply the nutrients evenly over an area. So no need to double-check the math.
An experienced gardener may recognize a plant’s need for fertilizer. For example, plants that are deficient in nitrogen may start turning light green or yellow. Similarly, purple foliage (on an otherwise green plant) is a telltale sign of phosphorus deficiency. The only true way to determine how much fertilizer a crop needs is to conduct a soil test. Most states offer soil samples through their Cooperative Extension Service at no charge (or for a small fee). A soil test ensures that the correct amount and type of fertilizer will be used on your plants.
Next time you’re in the garden center selecting fertilizer, don’t let the numbers on the package intimidate you. Just consider what your plants need and match their needs to the numbers. You, and your yard, will be fine!