Your plants use the nitrate or nitric form of nitrogen immediately because they're soluble. But over-watering can wash them away. The ammonium types of nitrogen will take from two weeks to three months for the plant to use, but won't leach out of the pot. When using fertilizers, check the package to see which kind of nitrogen you're getting. When fertilizing, remember that too much nitrogen can be as bad as too little.
Plants can suffer nitrogen burn or grow so much foliage that they never flower.
Phosphorous stimulates budding and blooming. Plants need phosphorus to produce fruits, flowers, and seeds. It also helps make your plants more resistant to disease. Phosphorus doesn't dissolve like nitrogen. The soil will hang onto phosphorus, not releasing it into water.