Step away from any 'Method' and lets look at fertilizers in general.
1) Plants need about a dozen element to live. Some are not thought of as fertilizers: Carbon, Hydrogen, Oxygen. The rest can be separated into fertilizers according to how much the plants use.
2a) If your soil or water is rich in a particular nutrient then you should not add that one, or add just a little bit, barely enough to replace what the plants are using.
2b) If your soil or water is deficient in a particular nutrient then you will add a somewhat greater than average amount of this one. Monitor the plants. They are great at telling you if a particular nutrient is at a good level or is lacking.
3) Macros are fertilizers that the plants need the most of. These are on fertilizer packages as 3 numbers, like 21-7-14, or 5-5-5 or 0-10-10. Fertilizers come from different chemical formulas. Some are easily available to the plant, but can get washed away when you water. Some fertilizers hold on to the soil stronger so do not get washed away too easily, but are not so easily available to the plants.
4) Secondary nutrients are fertilizers plants use a moderate amount of.
5) Trace minerals or micros are fertilizers that plants use very small amounts of.
On a package of fertilizer the first number is nitrogen. Nitrogen feeds leaves. All plants need nitrogen when they are first growing leaves (usually in the spring). Too much nitrogen will encourage too much leaf growth in plants where you want flowers and fruit. Fruit trees and most vegetables are usually fed with moderate nitrogen, and higher levels of the other two nutrients (might be 5-10-10). Lawns, and anything else where you are looking for leaf growth will be fed with something higher in nitrogen. Nitrogen is available in several forms. Nitrate nitrogen is available to the plants at cooler temperatures than other forms of nitrogen. Ammonia based nitrogen is not as easily available when the soil is cold, but can be so easily available in warm weather that it can burn the plants. Urea is a slower release nitrogen that needs to be broken down by soil microorganisms before the plant gets it.
Phosphorus is the second number. When you are trying to encourage roots, stems, flowers and fruit the phosphorus should be higher than the nitrogen.
Potassium is the third number. This should not be zero, but should be somewhere similar to the other numbers. Potassium helps plants maintain water balance in their cells.
Secondary nutrients are things the plants need in amounts smaller than the first three fertilizers. These are often already supplied in the soil, the water or as the chemical binder for some other fertilizer.
Calcium and magnesium are often in the soil, but sometimes not in enough supply for the plants. Usually OK, though. (Actually my own soil is somewhat low in calcium)
Sulfur is often combined with the other fertilizers. (Potassium sulfate is a common way of supplying both potassium and sulfur)
Iron is usually thought of as a trace or micro nutrient, but is used in such great amounts that I usually discuss it separately from the traces. Iron is available in several forms, most of which the plants cannot use. (You could plow rusty nails into the soil if plants could use rust- but they cannot). The best answer to iron is to get a chelated iron. This is iron that is bound up in a way that it is not easily lost in the soil, but plants can get it pretty easily. Another good way to supply iron is in organic forms like blood meal. Microorganisms will work on it and make the nutrients available slowly. (Microorganisms may do that to the rusty nails, too, but it takes quite a while to make the iron available, and some of it will not become available. Not a good way to supply iron to plants) Iron is commonly bound up in the soil in ways that plants cannot use. So supplying iron helps, even if a soil test shows there is some iron in the soil.
All the other minerals that plants need they will use in very small amounts, and too much can be toxic. They are lumped together as trace minerals. Some soils are deficient in a single one (zinc is a common deficiency) but before you attempt to supplement any of these in extreme amounts it is much better to supply a balanced but very low dose of all of them. Address deficiencies if they show up.
Alternately, if you already know there is a problem, then address that. A client of mine several years ago used a well that was high in boron. We had to be very careful to NEVER use any boron fertilizer on his property.
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Fertilizer is available in a bewildering array of packages, but it all breaks down into 3 basic forms.
Fast release fertilizers are generally water soluble salts. They can green up a plant very quickly, but get washed away when you water. Applying them weekly during the growing season is common.
There are two problems with this:
The fertilizer that gets washed away often ends up in aquifers, rivers and lakes. This can make the well water toxic, and fuel big algae growths called blooms. Too extensive to go into here, but this is a bad way to constantly fertilize your garden. A boost now and then with these products might be called for, but don't keep using them all season.
This type of fertilizer is commonly used in hydroponics, where the water is circulated for re-use, and tested for nutrient levels. The plants in this sort of system use all the fertilizers and small amounts are added to match the amounts the plants use.
Miracle Gro, Rapid Gro, and similar products are these fast release types of fertilizers. Most lawn food is a blend of fast (so your lawn greens up quickly) and slow release (so it stays green until the label tells you to reapply). In hydroponics they are usually using simple chemicals that supply just the targeted nutrients.
Slow release fertilizers can come from 2 sources. Man-made slow release fertilizers are the same fertilizers as the fast release materials, but are enclosed in a pellet that slows the release of the fertilizers so just a little bit trickles out each time you water. Osmocote is one example of this type of fertilizer. Slow release can also be from the chemical form of the nutrients. (see the nitrogen info above)
Natural slow release fertilizers are animal, plant or mineral based materials that need to be acted on by soil microorganisms to release the fertilizer elements to the plants. These are the best to use when you have a rich, healthy soil, with a thriving ecology of microorganisms and macroorganisms like earthworms. Most often these are applied just once or twice a year. For example, in a vegetable garden you might do a pretty complete prep job setting it up, and incorporate plenty of these organic materials the first time, then rake in small amounts each spring, and maybe in the fall if you live in a mild enough area to keep the vegetables going year round. You can also use these materials when you are preparing soil (or soil-less blends) for containers. These are the materials generally considered 'Organic'.
