There is a pervasive idea that nitrogen is for top growth, phosphorous is for root growth, and potassium is for the general well being of the plant. This leads us to believe that a little more of the right nutrient can cause roots or blooms or ..... to grow larger or with more profusion. Someone even invented a little rhyme to help us remember what NPK are supposed to be for,
"up - down - all around". Don't be taken in, it's a myth. Each nutrient is equally important to growth of plants' above ground parts, roots, and its well being, and for best growth/ vitality there is an ideal ratio of nutrients. I'll provide a couple of links below for you to consider how best to go about your nutritional supplementation.
For conventional container culture, fertilizers with an NPK
ratio of 3:1:2 will almost always be the best choice, and you'll find that repeated over and over in texts and other scientific literature. 3:1:2 ratio fertilizers provide nutrients in a ratio that closely matches that at which plants actually absorb/ use the nutrients. Examples of 3:1:2 ratio fertilizers: 24-8-16, 12-4-8, 9-3-6 (I use 9-3-6 for averything I grow, occasionally supplementing that ratio with a small amount of 0-0-3 when more potassium is required (as in hibiscus).
Understanding Nutrition
Fertilizer – Selecting The Right NPK Ratio
Al
