Across the board and on average, plants use phosphorous (P), the middle number, at 1/6 the rate of nitrogen (N). P is also present in ALL living tissues, including blooms, at the same %. This means there is no more P in leaves than in blooms. Because plants use 6 times more N than P, even popular 1:1:1 ratio fertilizers like 20-20-20, 10-10-10, and 14-14-14 supply 6 times more P than the plant will/can use. The high P formulas like 10-52-10 supply about 32 times more P than the plant can use. High levels of P also creates antagonistic deficiencies of Fe and Mn, so when you see yellowing as the result of these deficiencies, the first thing you want to do is grab more fertilizer to "green things up", which of course only exacerbates the problem.

Since high P formulas are comparatively so low in N, they need to be applied at high concentrations or N deficiencies can easily ensue. This raises the level of electrical conductivity (EC) and the level of total dissolved solids (TDS), which is totally unnecessary and makes it very difficult for plants to absorb water and the nutrients dissolved in water.

No one applies a high P fertilizer to en situ (wild) plants, yet they all seem to bloom and reproduce beautifully w/o our help.

If you do not know exactly what your soil needs/is lacking (haven't done an analysis), for an extremely high % of plants, the best you can do for them is apply an all purpose fertilizer that delivers nutrients in %s that are close to actual usage. Fertilizers with a 3:1:2 ratio like MG 24-8-16, or 12-4-8 deliver nutrients in those %s.

Average tissue analysis shows plants have an NPK content of about 10:1.5:7. To understand this, think that for every 10 parts of N in (all) tissues, the plant will have 1.5 parts of P and 7 parts of K. Plants use much more K than P (almost 5 times as much). You can also see that based on the fact that plants use 6 times more N than P, even the 24-8-16 and 12-4-8 blends supply twice as much P as the plant will use/want.

Al

What Al just said is your plants don't need it. Take it back. It's snake oil.
Linda C

Al, thanks for the information. I learned alot about what ratio I need in fertilizers. Linda C and Al, it appears your right it is snake oil. I plan to return it. Thanks
Ann

how about the easy answer ...

feed your soil.. and the plants will get all they need without snake oil ...

add good compost to your soil.. on a yearly basis... and you will never need to feed your plants ...

so .. i guess the next post is.. what is good compost.. lol ...

most cities give it away for free .... just a little hard work and exercise.. which we all need anyway ...

good luck

ken

Ken....that's too easy....and cheap. Not only does it provide a way of doing away with the clippings and detrius of the garden but it provides fertilizer and soil conditioner....for FREE? Is that for real????
You mean if you save all your pulled weeds, potato peelings, hedge trimmings, fallen leaves and maybe even add the grass clippings and the contents of your paper shredder you won't ever need to buy those MG products? Or that pelleted long lasting plant food? And then you won't need to buy bales of sphagnum moss as sopil conditioners??? Really?
Now...do I just pile it on top of the landscape fabric? or what???

I sure hope so!!!

I have to admit I buy synthetic fertilizer by the fifty pound bag, but I never put any on my garden. I have found no satisfactory replacement for it in my containers which do not contain any garden soil and the mix I use in them drains so well that regular fertilizer additions are required. Even in my containers I do not use 'super bloom' type fertilizers. Al

I agree with you, Al. I'm a firm believer in feeding the soil when it's in-ground plantings we're discussing, but, like you, I find synthetic fertilizers indispensable when it comes to container culture.

Bunny never mentioned whether she was growing in containers or the ground, so I'll suggest to her that the compost idea/suggestion takes for granted that she IS growing in the ground, and the direction to add it to soils would be something best avoided if her question was related to container culture.

Al

Decades ago farm supply stores had tons of "superphosphate".

This fell into disrepute.

But it must have done something for someone. Why were the farmers using the stuff in the first place?

There may have been a known deficiency in soils under tillage, in which case additional P would be helpful. The fact is that there is little scientific evidence to show real need for common high-P products. Historically, in the days when most plants were started in soil beds, the ground was usually still cold when seeds were sown. Cold temperatures reduce both solubility and plant uptake of P. High levels of P in the soil ensured that at least some would be available.

Al

I live in Iowa....
The farmers were using super phosphate because it allowed bigger crops, at the expense of soil health....but not to worry, we got weeds, we have Round Up ready soy beans, we got corn borers, root worm? We have BT and we even have corn that will have that bacillis right in the DNA of the plant...it's in the pollen! Not to worry, no worms at all.
All that stuff comes at a price....but the farmers wouldn't be able to produce without it and we would not be able to produce more food on less ground with out all the chemicals....so, commercially, we are damned if we do and damned if we don't.
But in my garden, I will use leaf mold, alfalfa and bone and blood meal.
Linda C

Thanks everyone for their advice and opinions! I was going to use the super bloom fert. on my annuals in my flower garden. I have a compost pile and use compost when I planted them, but when I saw "super bloom", I thought great I can have more blooms. I have now thanks to all of you realize that I do not need any extra fert., since I already use compost.
Thank you very much!
Ann

I wouldn't jump to the conclusion that simply adding compost eliminates the need for fertilizer. Finished compost actually adds little in the way of nutrients, even though it helps build a healthier soil. If your soil was deficient in a particular nutrient before adding compost, ;o) it will likely be deficient in that same nutrient after adding it. The only way to determine what your soil might need is by having it tested, or to some degree, by becoming a good detective and honing your ability to recognize symptoms of individual deficiencies.

IMO, the most important thing to take away from the discussion is that it is very good practice to feed the soil, and that high-P formula fertilizers are not so hot at living up to their claims - that you can do better (unless you have specific knowledge of what you need to add via a soil test) by providing a fertilizer formula closer to what the plant actually uses.

Al