"keith_nuttle" wrote in message
...
I live in Indianapolis. I went out to get some lawn fertilizer this
afternoon. Traditionally I usually buy a fertilizer that is equal, i.e.
15,15,15. All that was available was 22,3,5.

Am I wrong the the yard should be fertilized with an equal fertilizer?

If you want the same amounts, get garden fertilizer.

However - there's more to it - fertilizer ain't exactly uncomplicated

1) what to feed depends on what it eats and what you want.
High nitrogen is fed in the spring because you want lots of grass to
choke out weeds, and because grasses use mostly nitrogen.

2) people like even numbers.
Nobody asked the plant if it uses the three evenly (they don't, and
they don't at different times, and grasses don't use the same ratio as
carrots.)
Kind of like demanding a coffee with equal parts of water, sugar, and
ground coffee because the numbers are even.
Grasses use more nitrogen.

3) most soil already has some/enough of the three in it already, usually
phosphorous.
So even numbered fertilizers on lawns are usually a waste of money.

4) the ratio determines the weeds that will grow
there was a plot here a few years back where they had all these 30 x 30
plots that had only different fertilizer ratios
- damndest thing you ever saw - one plot was yellow with dandelions
while the one next to it was pure green grass, others had one kind of weed,
the next didn't.
So, if grasses don't need much phosphorous or potash, and plantain and
dandelion do... starve the weeds and feed the grass.

5) grass will choke out anything that invades its space, if it is long
enough. Bluegrass is mean as hell. period. Give it an edge and it will kill
its competitors.

6) - the kind of nitrogen (urea, ammonium nitrate, etc) determines what is
taken up by the plant and how fast - a couple common types don't move out of
the soil if it's below 50 degrees, while the plants can use the others at
lower temps. So you can put on 30-0-0 and have heavy growth, or you can put
on 30-0-0 and it sits because the plants can't take it up

7) plants that grow fast and happy in the fall don't make it through the
winter.
(this last one points out a possible fallacy in a common assumption. Grass
likes nitrogen and it will grow fast if it gets it. So is the fall
fertilizer 10-10-10 to feed the grass, or is it done to starve the grass of
nitrogen without losing root development, to prepare it for winter? To look
at it another way, can you get 0-10-10 lawn fertilizer?)

8) grass grows under the snow - slowly, of course, but it grows. 10-10-10
usually does not have the temperature-dependent-release types of nitrogen.
So if the fall feeding is to help the spring growth - it has to stay in
the soil. I am not sure if the base ingredients in something like 10-10-10
is less likely to leave the soil than 26-3-5 because it is made for loose
tilled soil, but it sure has bigger pellets.

So even numbers may not be exactly what you really want.

all that said, I put the year's leftover garden fertilizer on my lawn in the
fall and it comes up at about a half-rate coverage.
( And thinking about it, I do get healthy broadleaf weeds each year.)

fwiw