When I started really paying attention in the garden and decided to learn more and do a better job, these three letters seemed so intimidating to me. I understood N – Nitrogen. P stands for Phosphorus and K stands for…….Potassium. What?! That’s where I would get hung up. I know it’s the chemical but K for P? So the first struggle for me was to remember N-P-P, not K, then I had to remember which P was which. (Have I confused you enough?!)
Here’s a little secret – keep it in alphabetical order. Nitrogen, Phosphorus and Potassium.
With that, I think now is a good time for a little refresher on fertilizer. I’m going to cheat a little bit on this post, but I found this explanation on the Monrovia Nursery website and I thought they did a much better job of explaining than I would have (see above!!!), so here goes.
When the nutrients around the root zone are depleted, plants suffer. Without regular nutrients, growth slows, flowering is inhibited, and the plant becomes vulnerable to pests and disease.
There are three main food groups that plants need for vigorous growth, expressed as N-P-K. Each nutrient is responsible for different types of growth and aspects of plant health. All are essential in varying amounts.
N – Nitrogen promotes leaf and stem growth. It’s important for evergreens, foliage plants and ornamental grasses.
P - Phosphorous relates to flower and fruit production, which is crucial to fruit trees, roses and ornamental berry-producing shrubs.
K – Potassium helps a plant’s immune system fight disease, and also helps fruit to ripen more quickly.
Each fertilizer is labeled with three numbers that indicate the strength by percentage of each nutrient. For example, 23-6-8 means that the product contains 23% nitrogen, 6% phosphorous, and 8% potassium.
Organic and synthetic. Organic fertilizers are produced naturally and include compost or manure. Synthetic fertilizers are produced chemically, and include most granular fertilizers. Synthetic fertilizers contain exactly what’s on their label expressed as N-P-K. They are fast acting but here today and gone tomorrow, so you must apply them often. Organic fertilizers also bear N-P-K percentages on the label, but these are usually lower numbers. Organics are slower to take effect because they must interact with soil microorganisms, but are long lasting. Natural fertilizers contain many of the lesser nutrients too, which improve soil and overall plant health.
No need to overthink this information. Most plants are just happy to get whatever they get, but some plants such as roses or citrus do better when given the correct ratios of these nutrients. Any good nursery can help you with this if you still aren’t sure what to do.