Most fertilizers sold for home use have directions on the package. The simplest and surest way to apply them is to follow these directions. It’s always safe to feed half as much as the package recommends, but twice as often.
After adding any soluble fertilizer to the soil, water thoroughly to dissolve and dilute the nutrients and to keep the fertilizer from burning your plants. Packaged fertilizers often have a high salt index; follow the package directions to avoid fertilizer burn.
Because plant nutrients in all fertilizers are basically the same, just as all vitamin C is the same chemical, the main difference in fertilizers lies in their convenience. Different formulations are made to be applied in different ways; the right fertilizer for you depends on how you prefer to work.
When selecting a fertilizer, be sure it contains the nutrients you want in the amounts you want, then decide how you prefer to fertilizer. Some of your options are:
Sold as either a soluble powder or a liquid, these are made to be dissolved in water. After they are dissolved, they can be sprinkled on, watered on with a watering can, sprayed on the leaves, or applied with irrigation water.
These are put on as granules or pellets. They can be broadcast, dug into the ground, or placed in pockets where the plant roots can find them.
These formulations release nutrients over a long period of time. They are always mixed into the soil. Some are tablets that are dropped into holes, some are spikes that are pressed or driven into the soil, and some are pellets or granules that are stirred into the soil.