NPK ratios

[cazp]

Out of interest ... if two brands of feed have the same NPK ratio - will they be of equal benefit to a tree (or vegetable or other plant etc) or will the benefit vary, say, on the quality of it's ingredients?

[Newton]

Unless the active ingredients are not bulked up with different materials.....which the might be...the ratios would still be the same...

[Aberdeenplotter]

there are various factors that could affect matters. e.g. how soluble the ingredients are. A slow release fertiliser may feed a plant over a fairly long period whereas a different type may give a plant an immediate boost but do nothing for the plant later. Did you have a reason for asking or did something just give your brain cells a jolt and make you wonder?

[dod]

They could also have different trace nutirents, which would not be included in the N:P:K ratio

[FB.]

As above: the trace nutrients will vary.
Manures and composts are a good source of trace nutrients but unless they're fresh, they will be fairly low in nitrogen. Fish, blood and bone, for example, should also have lots of trace nutrients.
Synthetic fertiliser may have no trace nutrients.

[Two_Sheds]

What are trace nutrients?

[cazp]

Did you have a reason for asking or did something just give your brain cells a jolt and make you wonder?

I was comparing two feeds which had the same ratio and one was cheaper than the other... and it got me wondering. Hoewever I am not so sure how they stacked up as regards how often the feed lasts etc... hadn't considered that!

[FionaH]

Cheaper doesn't mean worse! I work in a garden centre and the cheap tom food is just as effective as tomorite, we just buy it at a discount