Joshua you have it a little mixed up.....the first number is for the top growth and has a lot to do with chlorophyll. This is why its soooo green and grows a lot. Most soil has a lot of phosphorus in it, and this helps the plant with metabolism. The only time that you normaly need high numbers of this is with new grass becouse it dosn't have the roots to pick it up out of the soil yet. And the last one potassium is for the roots.
Now I see most of you guys you the same thing 8-8-8 19-19-19 10-10-10
if you think about it you are all putting down about the same thing. The number is the % in the bag not by weight. And Smithsonmi I bet the stuff that you are using has a lot of salt in it do to the price. It sounds like a cheap feild grade.
So my question is this why whould you want a LOT of top growth? When that means more mowing?
Why not make the roots healthy so that it can make it through the summer heat?
Remember a plant only has so much growth in it, so if you make it grow from the top the roots suffer, and the plant will die under stress.
Grass with no roots need a LOT more water.
This is why we use a lot of 8-4-24. You still get that nice green look, but your making the grass put a lot of energy into the roots. So as summer comes along my grass is greener longer. And by the way I don't get that bad growth spurt.
And as a rule of thumb the middle number is usually 1/2 the first.
But if you have a plant that you want to flower a lot then you need a real low first number HIGH second and lower third. Just take a look at Miracle Grow.
Early bird may get the worm...but the second mouse gets the cheese.