How to measure fertilizer?

[gary350]

If you need to fertilize a certain plant how do you know if 1 teaspoon is too much or too little?

My soil test shows, Nitrogen 0, Phosphorous 100, Potassium 98. This year my garden needs NO P&K. It only needs N nitrogen.

I have already learned that nitrogen does not stay in soil very long and hot dry 100° temperatures makes nitrogen be gone sooner than 4 months. After winter next summer soil will be very near 0 nitrogen.

After having 36" of rain another soil test might show lower P&K numbers. I am shooting in the dark unless I get another $15 soil test after having 36' of rain. Soil test says, rain will lower P&K and remove N.

This year my garden gets NO P&K all summer.

I bet commercial farmers do soil tests once a month and probably know from experience what NPK will be all summer with no soil test.

Plants need P&K but no information can be found on how much P&K plants remove from the soil?

I am trying to learn how much fertilizer each plant really need. At the moment in my garden my guess is plants need NPK = 5-0-0 and corn will need 30-0-0.

FFA online shows corn only needs nitrogen. Many farmers plant 2000 acres of corn, they recommend row spacing = 32" and seed spacing = 5" and a certain number of lbs. of nitrogen per acre. FFA nation wide maps recommends nitrogen according to, geographical location. air temperature and rain fall.

 

[oneeye]

Most fertilizers have recommendations on how much to use. I use half the manufacturer's recommendation because I can always repeat and add the other half later if needed. As far as using nitrogen in the hot heat of the Summer, it will cause problems to your plants in hot Summer. Spring and early Summer would be the best application times.