My sandy soil is well-supplied with phosphorous and deficient in potassium.
So I have to look for lawn fertilizers which will give me N and K and avoid
applying more P. You might be able to find 'winterizer' formulas which
contain more potash.

Thanks. This causes me to take a look on the use of Fertilizer with
Halts Crabgrass Preventer and the use of Starter Fertilizer. I decide
to replace both with Winterizing Fertilizer. This cuts down the annual
amount of phosphate, while at the same time increase the annual amount
of potash level. I also replace the use of one serving of organic
fertilizer with Winterizing Fertilizer.

The revised plan is like this:

Nitrogen Phosphate Potash
-------- --------- --------
Late-Mar: Scotts Winterizer Fall 4.6 lbs 0.6 lbs 3.0 lbs
Lawn Fertilizer

Mid-Apr: Milorganite Organic 6.9 lbs 2.3 lbs 0.0 lbs

Mid-May: Scotts Winterizer Fall 4.6 lbs 0.6 lbs 3.0 lbs
Lawn Fertilizer

Early-Sep: Scotts Winterizer Fall 4.6 lbs 0.6 lbs 3.0 lbs
Lawn Fertilizer

Early-Oct: Milorganite Organic 6.9 lbs 2.3 lbs 0.0 lbs

Early-Nov: Scotts Winterizer Fall 4.6 lbs 0.6 lbs 3.0 lbs
Lawn Fertilizer
-------- --------- --------
Total: 32.2 lbs 7.0 lbs 12.0 lbs
-------- --------- --------
Expected: 28.7 lbs 7.2 lbs 14.4 lbs

Seem like the annual amount becomes very reasonable. This means I can
achieve what I need to do without the use of expensive Green Sand
while still manage to use some organic fertilizer. The only thing that
I don't like is that I will need to apply chemical fertilizer for 4
times instead of 3 times. Hopefully soil test tells me that the potash
level in my soil is still OK; then I don't need to follow this plan
that strictly. But this plan will probably be the general guideline of
what I am going to do.

Obviously, I need to apply crabgrass preventer separately. This is OK.

Measure a 100 square foot area. Measure 5 - 10 pound of greensand (the
recommended amount for surface application on 100 square feet). Then
experiment to find the setting that lets you spread the full measure of
greensand on 100 square feet. (I would hazard a guess that the spreader
would be set on one of its lowest settings.)

Thanks for the instruction. I hope I don't need to do this because
Green Sand is very expensive. But I never know. This info may come in
handy.

Jay Chan