Question
I want to know thedifferent types of fertilizers avilable, their usage and when to apply them for effectiveness ?

Answer
I would recommend that you take a look at this article for a basic understanding of what fertilizers are, and what they do:

http://www.suite101.com/article.cfm/18505/106509

Also let me explain following:

A plant grow by putting together certain essential elements (like input of raw materials into a factory process) and using these to create carbohydrates. Plants actually manufacturer their own foodstuffs. These carbohydrates (similar to our foods) are then used for growth, e.g. to create leaf tissue, etc.

The essential elements (raw materials) are detailed in the above articles. Most of the essential elements the plants get from water, air (carondioxide), and from the soil.

Whereas carbon, hydrogen, and oxygen are readily available, the nutrients in the soil can be depleted over time. In this context, it is usually - not always - but usually - NITROGEN, PHOSPHORUS, AND POTASSIUM which are depleted.

When we talk about fertilizing, the goal is usually to add back the right amounts of nitrogen, phosphorus, and potassium to the plants.

The reason is that these 3 nutrients are required by the plants in relatively large amounts, and all 3 are either bound tightly by molecules in the soil, or leach from the soil (drip through the root zone with the water).

The fertilizer industry has tried to make a simple over view such as nitrogen being responsible for leaf growth, phosphorus for roots and flowering, potassium for cell structure and plant health, etc, etc. Unfortunately, it is not quite as simple as that. The nutrients play an interactive role and so it is not as clear up as outlined above.

When gardeners talk about fertilizing plants it is typically the addition of these 3 nutrients (specifically): nitrogen, phosphorus and potassium. The other nutrients are either taken from the air and water by the plant (no restrictions) or required in so small amounts that they are not typically depleted in the soil (although it can happen from time to time).

The reason you then have different types of fertilizer is because different plants require different amounts of these nutrients:
e.g. grass and other leafy plants consume a lot of nitrogen but little phosphorus and potassium. Flowering plants consume large amounts of phosphorus and potassium, and too much nitrogen will limit flowering. Flower bulbs are heavy users of potassium. Perennials require relatively high levels of nitrogen in early spring, but then benefit from a flower formular later.

Based on these differences in consumption by plants, the fertilizer industry has then created various "formulars" for various plants.

If you look at the lable of fertilizers you will find 3 numbers: N-P-K such as 10-2-6, 33-3-3, 10-15-10, 20-20-20, etc. These 3 numbers mean percentage by weight of NITROGEN (N) - PHOSPHORUS (P) AND POTASSIUM (K).

E.g. a 10-2-6 forumlar has 10% nitrogen, 2% phosphorus and 6% potassium. Since nitrogen is higher than phosphorus/potassium, it does well for leafy plants (but not for flowers). A 33-3-3 or 29-3-4 is typical lawn fertilizer grades.

A 10-15-10 or 15-30-15, or even 20-20-20 is good for flowering annuals.

A 20-10-10 is excellent for perennials in early spring.

It is all a matter of pre-packaging the right amount (ratio towards each other) of nitrogen, phosphorus and potassium.

To make this easier for consumers, the manufacturers have also labled the fertilizers such as "lawn fertilizer", "rose food", "annual plant food", etc.

If you look at a lawn fertilizer it may have figures such as 29-3-4 and the annual plant food may have numbers such as 14-14-14. Even without the names, you could see from the figures that the 14-14-14 has a lot of phosphorus and potassium (compared to nitrogen) and thus do better for flowering plants whereas a 29-3-4 fertilizer the nitrogen dominate and is best for lawns.

Finally gardeners usually divide fertilizers into two main groups: organic and inorganic (synthetic or "chemical").
The difference is that inorganic fertilizer are produced in factories, and prepackaged. They are typically salt based. Organic fertilizers are made from recycled products, such as sewage sludge, manure, blood and bone byproducts from slaugter industry, etc. The latter is also reprocessed and prepackaged (although some gardeners like to add composted manure directly to plants).

The advantage to organic fertilizers besides being recycled is that they are usually more gentle and can supply fertilizer over a longer period of time than the synthetic counter parts. Both are excellent fertlizers, howevers.


The reason we do fertilize is because plants through their growth remove essential elements from the soil. In nature, when these elements were depleted, the plants would die from one area and re-appear (through seeds) in other areas that had plenty of fertilizers available in the soil. Since we would like our plants to continue to grow (whether in a lawn, in a flower bed or in a pot indoors) we must manually resupply the elements which the plants remove by their growth.

We do this through fertilization. I recommend that you always read the lable on the fertilizers carefully and only apply the minimum amount stated. Too much fertilizer can kill plants.

I hope above helped you.