Oh boy, that is a classic discussion. Do a search, especially in the grass/lawn forums...

They all work.

You can choose what you prefer. Or you can try both, then compare.

In the end, the fertilizer must break down into the small bits and pieces the plant roots can take up.

Bottom line -- The kind of fertilizer doesn't matter; the end result is the same.

As far as fertility goes, they're basically the same assuming you are referring to water soluble fertilizers (though one thing to keep in mind is that the analysis - the percentages of N,P and K - in chemical fertilizers is often much higher than that of organic fertilizers, increasing the likelihood of causing salt burn or disrupting the activity of soil microbes if you aren't careful).

If you are talking about slow release, go for organic as those will also improve the structure and cation exchange capacity of your soil.

Ryan

It's not as simple as the classic argument that plants take up only basic elements/nutrients and that it doesn't matter whether it's organic or synthetic.

That's what chemists deal with.

As gardeners, we have to deal with the real world of soils.

Soils are more than just minerals and organic particles. Soils are soils and not just "dirt" because of something called "edaphon" -- the collective term for all the living things in the soil. It's this living component that we, as true gardeners, must take care of. It's this living component that breaks down organic matter, turning it into useable nutrients and other nice bits that plants benefit from. It's this living component of the soil that allows us to have the healthiest garden possible.

Organic fertilizers don't just feed plants; they feed the edaphon. Organic fertilizers also break down into humic substances that pull soil particles together into crumbs.

Synthetic fertilizers don't feed the edaphon and worse, they actually kill off much of the edaphon and diminish the soil structure and texture.

No, this is not an organic gardener's soap box. Talk to any soil scientist or even an organic chemist.

If we stick to the argument about elements being simply elements then we might as well treat our garden soils as test tubes or hydroponic containers.

Joe

What Joe said. : ) And if you don't believe him try gardening in both ways. You will see a difference in your soil structure and texture.

Diana, who has grown to love the smell of alfalfa pellets/meal : )

Joe,

Application of a synthetic fertilizer won't automatically damage your soil structure or disrupt edaphon. NO3- is NO3- no matter whether it comes from a microbe nitrifying the NH4+ liberated from your bloodmeal during decomposition or if it comes from a bag of potassium nitrate. What will damage your soil food web is excessive salts whether it comes from too much ammonium chloride or too much chicken manure.

As I noted above, your likelihood of over fertilizing is higher with many concentrated synthetics than with organic materials but either is possible.

Appreciate that this comes from someone who doesn't use synthetic fertilizers - mainly because I can get all the fertilizer I need from free organic sources.

Ryan

P.S. I'm taking fertilizers and plant nutrition this quarter at CalPoly and would be happy ask my instructor (Terry Smith) for clarification on anything you think I'm mistaken about. I'm quoting points I'm reasonably sure I remember him making in lecture but I could be confused.

Brainless moment. I ought to point out that even without salinity issues, nitrates can still be a problem: they can stimulate microbes to break down all organic carbon in the soil, including humus which will have a deleterious effect on your soil structure.

Again, this has nothing to do with the source of the nitrates but with the concentration and again, higher concentrations are more likely with high analysis synthetic fertilizers.

Ryan

Ryan:

How does chicken manure end up with excessive salts? I know that bagged steer manure (the stuff from feed lots) contains damaging salt because of the process that leads to the stuff in bags but I don't know how salt ends up in chicken manure. (also fyi -- I NEVER recommend bagged steer manure for any garden use.)

And you're right -- synthetic fertilizers don't "automatically" disrupt edaphon or soil structure. First, there are plenty of newer formulations that are fairly safe. Secondly, one application in itself is not the problem; it's not a chemicals-in-the-lab thing -- it's the accumulation in real life.

One more point that I didn't make in my initial post is that organic fertilizers provide for a wealth of recognizable and beneficial trace elements and other compounds that synthetics don't and can't provide. The soil science institution kind of got stuck at 16 elements that plants need -- a chemist' point of view. Hence why synthetic fertilizers are usually the familiar formulation of simply N-P-K. Granted quite a few newer formulations include many of the secondary and trace elements; but none contain more than the 16 "known" nutrients. Plants actually do need more than 16 nutrients/elements and our soils need more than 16 elements and salt.

I teach special programs for CalPoly (SLO). I'm sorry but I don't know Dr. Smith.

Joe

Joe,

I think I may need to rephrase. When I apply organic matter to my garden, fertilizing is not my primary concern, soil health is. "Shot in the arm" fertilizers whether they are organic or synthetic are for a short term fertility problem:

"Oops, I probably shouldn't have tilled four inches of sawdust into my garden!"

or

"I really want to garden but my soil was covered by a driveway last year and has very limited fertility."

or

"I just need a little bit more nitrogen to get me through the season and my source of chicken droppings dried up."

etc.

I can't say enough good things about adding compost, coffee grounds etc. to the garden. But that isn't fertilizing. To my mind, organic fertilizing is adding blood meal, bone meal etc. In other words, organic materials with relatively high analysis but lower potential humus value.

Ryan

So... the bagged steer manure at the nursery is bad news? How about chicken manure?

Betty

Bagged steer manure is very low in real nutrients, loaded with salts and even the so-called "weed-free" stuff has weed seeds.

Bagged chicken manure is okay. Not great.

Joe

Joe,

Thanks for the feedback - disappointing as it is. For those of us with old backs, it's easier to drag around a bag than to shovel, load and unload manure!

BettyN

Maybe I am just "blessed" with good clay/loam soil, but I have never found a need to add fertilizer, chemical or organic. I do make lots of compost containing nothing but vegetative matter grown on the property and requiring being disposed of in some manner. The addition of finished compost spring and fall will feed quantities of soil microbes quite capable of producing nutrients in sufficient amounts to feed my plants year around. Al

Al - do you grow plants that are considered "hungry"? - like roses or clematis?

BettyN

I have several rose beds, one of which I under plant every year with 200 tulips. Several Clematis, two which threaten to consume the house and one 20 feet up a cherry tree. Al

Well - that's encouraging...

BettyN