Help settle a discussion about the "numbers" in fe A co-worker and I have been discussing this in regards to growing flowers. And now we're both a little confused by info we've found online. There's no argument that the numbers are for Nitrogen- Phosphorous- Potassium (N-P-K) and that Nitrogen is for "growth". But there's mixed info on the other two. Some sites say Phosphorous aides flowering and Potassium is for "root development". But some info has the last two "switched". I've always thought the "middle" number was for flowering... and she subscribes to the "up-down-allaround" theory (growth, roots, flowering). So.. which is it?
Nitrogen is for green growth. Too much makes the plant susceptible to insect and disease infestation, though. Phosphorus is for bloom production, but it also helps with the root growth and cell production. We use 11-41-8 as a transplant solution and then later as a bloom booster. Potassium helps overall growth and disease resistance. It is also essential for photosynthesis. without the potassium the plant will starve to death, even with adequate amounts of nitrogen available. the plant cannot utilize the nitrogen. Confusing it can be, but the plants need all of these and others nutrients too, but they do tend to overlap in their "duties". I hope this helps a little.
So... let's make this simpler... I go to the store to buy fertilizer because I want something to boost flower production. Do I get something with a higher "middle" number? Or higher "last" number?
Cheryl, glad you guys had this discussion because I'm confused as well. I would like to know once in for all. The fertilizer containers and many websites are just as you say, complete opposite order. gsdruth
Oh, gee, I'll stick my toe in this puddle, but remember, I'm not an expert! N-P-K roughly translates to leaves-flowers-roots. As Carolyn said, all three (and trace elements, also) are needed, but if you want to boost blooms, say in zinnias, get a fertilizer with a higher middle number (5-10-5). If you are fertilizing lettuce, get a fertilizer with a higher first number (10-5-5) and if you are establishing a transplant, after a week or so you may want to give it a feeding with a higher last number fertilizer (5-5-10) to help with getting established in its new home. I beg the question and just give everything either a side dressing of composted manure, or water with manure tea.
Cheryl, Jane made a very good point with what fertilizer for which plant...Remember each plant species will have different needs. You need to know what your plants "needs" are. Are you growing for flower production? use a high middle number (if it is available and something such as a rose fertilizer is one of the easiest to find and has a consistently high middle number no matter what brand you have available) you may need to stock up on it early in the year if all you have is a walmart near you. But your plant will still need both of the other numbers and trace elements. A high N number for green plant growth if you are looking for quick or greenup growth, lettuce is a very good example as it is a leaf crop. I use a 0-60-0, sparingly (1/2 cup for 50' row), for the root crops when I plant and an 11-41-8 for transplanting and a bloom booster. The potassium is important for both the root development and flower development. The last number (K) is for overall support of healthy growth, without it the other elements can't work efficiently, either. All plants will need them all in some amount or another. Try to get fertilizers that come from natural sources if possible. Synthetic fertilizers don't provide as healthy of growth as natural ones... in other words the plants are more susceptible to disease and insect infestations. does this help explain the need of them and how the plant uses them a little more clearly? Just keep in mind that the plant is never going to use only one of these elements without the others and that they need all of them and that their functions for the plant are going to overlap to a certain extent. People who put high nitrogen fertilizer for their grass get fast greenup but very little root support and very soon ( as soon as there is stress) you will notice that the lawn is looking spotty, rusty, dead in spots etc, because the "grass" fertilizer doesn't give the plant overall nutritional support. It has has no root growth and with out the root growth it can't sustain its green growth as soon as their is a dry spell. Kind of like us eating only fruit all of the time....It might taste good, but eventually you will see your health not as good as it should be because all of the body's needs are not being met.
Thanks Jane and Carolyn. Case in point... I bought an Esperanza earlier this year. It was probably about 2 feet in height. The darn thing is getting huge... probably around 5 feet tall. When I planted it I used some Osmocote which is 14-14-14. But there isn't any sign of a single flower bud. I've noticed others in the area are in full bloom. So I was wanting to give it a little "nudge" to see if it would bloom. So basically, in order to give a boost to it's flowering ability, I need a fertilizer with a high "middle" number. So, I'll just let my co-worker know... it's the middle number/phosphorous that promotes blooming... NOT the last. So much for her "up(growth)-down(roots)-allaround(blooms)"
Cheryl, I don't think that the "up, down, all around" is necessarily wrong, just the way we think of it can make it confusing. The "all around" to me means it supports both the N and the P not just for making blooms. Without the K the P won't be able to do it's job. And without the P the K cannot do it's job either. Same for the N, without the P or K, it cannot work alone, either.
I understand Carolyn. She was just using the "up-down-allaround" as an easy way to remember what did what... nothing technical... just a memory-aide. Guess now she'll just have to come up with a new little saying.
