What Is N. P. K
I Want To Know The Full Meaning Of N P K Which Always See Written On Fertilizers' Bags
The letters refer to Nitrogen (N), Phosphorus (P) and Potash (K). A way to remember what they do is UP, DOWN, and ALL AROUND. Nitrogen causes foliar growth so growing UP and green leafy growth. Phosphorus causes root development so DOWN into the root system, and Potash is ALL AROUND so helps with development of the entire plant. This is the general idea. Another way of looking at is that for blooming plants they need the Phosphorous and Potash to be greater in number that the nitrogen to encourage blooming. New plants usually need less nitrogen and more Phosphorous and Potash to get going. I hope this helps.
These are the primary nutrients in fertilizer. N= nitrogen. P= phosphorus. K=potassium (remember high school chemistry?) Plants need all 3 of these plus some micronutrients. The best way to know what your plants need is to do a soil test. Done at the county extension service in your state, it will tell you what you have and what to do to correct any deficiencies. Many plants do fine with just adding compost into the soil. Fertilizer isn't necessary. Plants grown in pots in "potting soil" are a different matter. Even here, different plants have different needs. Nitrogen leads to good green leafy growth which sounds good but on a flowering annual, leaf growth may come at the expense of flowers. Cosmos are a good example; you get a lush, great-looking plant but few blooms. So there is no one fertilizer that fits all plants, esp. perennials. Here is more info: