Best Fertilizers for Plants – A Full Guide

Introduction: Fertilizers are food for all plants. Fertilizer helps farmers feed our growing population and plants require 17 essential nutrients in the soil to survive and to grow.

A step by step guide to best fertilizers for plants

To grow healthy crops full of nutrients, farmers want to ensure they have healthy soil. Without fertilizers, nature struggles to replenish all nutrients in the soil.

Common fertilizer nutrients

Fertilizers help replenish these nutrients after each plant harvest. Nitrogen, phosphate, potassium, and sulfur are the most important nutrients for high crop yields and sustainable food production. All plants require certain mineral nutrients to survive. These minerals occur naturally in the soil and taken up from the soil by the roots of the plants. Most soils generally have enough of these minerals to keep plants healthy. However, some nutrients are gradually used up by the plants, or are washed out of the soil, and need to be replaced to keep optimal growth and appearance. The common mineral nutrients that need replacing are Nitrogen (N), Phosphorus (P) and Potassium (K).

Nitrogen (N) makes up 78 percent of the air we breathe. It is inert and insoluble in this type meaning plants cannot use it. To manufacture nitrogen fertilizer, it should be removed from the air and combined with hydrogen to make ammonia. Ammonia is used in two ways that are it is applied directly to crops as a nitrogen fertilizer, or it is used as a building block to making other nitrogen fertilizer products. Different nitrogen products have different properties and levels of nitrogen that can be used in different climates and cropping patterns found around the world.

Fertilizer Components.
Fertilizer Components.

Phosphorus (P) is present in all living cells and is necessary for all forms of life. Found throughout our bodies, it is concentrated in teeth and bones. The source of phosphorus in fertilizer is phosphate rock, which is normally mined from the earth’s crust then reacted with different kinds of acids to produce different phosphate products.

Potassium (K) is found throughout nature and is found in our bodies in muscles, skin, and the digestive tract. Good health requires sufficient intake of potassium, and plants obtain it from potash fertilizers. Plants use potassium for functions like photosynthesis, protein formation, and water use. Potassium, or potash, and is mined from naturally occurring ore bodies that were formed as seawater evaporated. The deposits are a mixture of crystals of potassium chloride and sodium chloride is also known as table salt. After it is mined, the potassium chloride is separated from the mixture and effects in a granular fertilizer.

Sulphur (S) is necessary for the production of amino acids, which are the building blocks of proteins found in all living things. Sulfur helps give crops like onion, mustard, and radishes their characteristic color. While it can be found naturally in the soil and it is not always in a form plants can use.

You should not miss the Best Manures for Flowers.

Fertilizers are manufactured mixtures of chemical products that have N, P, K, and other necessary nutrients. They are spread over the soil to re-supply the soil with a good amount of these nutrients. The three numbers on the front of the fertilizer bag represent the percentage by weight of N, P and K in that mixture.

Methods of applying fertilizer

Soils require fertility maintenance. Soil is a natural body of finely divided into rocks, minerals and organic matter.

Three ways to apply fertilizer are explained below.

  • The nitrogen in chemical fertilizers is highly water-soluble and carried to the roots by irrigation and rain. Thus, you don’t want to mix these materials into the soil, but you do need to water your garden if rain doesn’t fall within a day after you apply them. Organic sources of nitrogen are most accessible to plants if mixed into the top 2 to 3 inches of soil.
  • Phosphate moves very slowly in the soil. Phosphate-containing fertilizer two inches below the seed when you plant or by tilling it into the soil during spring preparation.
  • Work potassium fertilizers into the soil using the broadcast methods and do not allow potassium fertilizers to contact plant roots.

Organic fertilizers versus synthetic fertilizers

Chemical/synthetic fertilizers are manufactured using synthetic substances that usually have highly concentrated forms of nitrogen, phosphorus, and potassium.

These fertilizers work very quickly because they feed the plants directly. But they do come with a downside they do not develop the soil itself and they can, over time, even destroy the beneficial organisms needed for healthy soil. When you use large quantities of this inorganic stuff over and over again, its byproducts will build up in the soil and in time they can hinder plant development.

Organic/natural fertilizers often use alfalfa meal, cottonseed meal, or fish emulsion to give nitrogen; bone meal or rock phosphate to give phosphorus, and kelp meal or granite meal to provide potassium. The downside here is that they work more slowly, first breaking down in the soil into forms that the plant roots can more easily absorb, then making their way up the plant roots to hungry plants.

Organic/natural fertilizers, on the other hand, don’t feed the plants directly but rather add essential nutrients to the soil where they become obtainable to the plants, more slowly, over time.

Fertilizer components


Macronutrients are nutrients necessary by plants in relatively large amounts for optimum plant growth. The three major nutrients contained in fertilizers are nitrogen (N), phosphorus (P), and potassium (K), represented by three numbers that appear on the bag. A complete fertilizer will contain all three of the main plant nutrients. Other macronutrients contain calcium (Ca), magnesium (Mg), and sulfur (S). Many soils have adequate phosphorus, in which case the fertilizer used should contain only potassium and nitrogen. An easy soil test will tell if phosphorus is needed.


Micronutrients are nutrients most plants require in small quantities and are sometimes referred to as trace elements or minor elements. These nutrients include boron (B), chlorine (Cl), copper (Cu), iron (Fe), manganese (Mn), molybdenum (Mo), and zinc (Zn) are often obtainable in sufficient quantities in the soil but are present in many fertilizers. Micronutrients are sold as individual nutrients.

Types of fertilizer in plants

A wide range of fertilizers is obtainable for gardeners. You can choose from different combinations of nutrients that come in a variety of forms. The key to selecting a fertilizer understands what nutrients your plants need.

You may be interested in Best Manures for Vegetables.

Inorganic Fertilizers

Inorganic fertilizers are mined or synthesized from non-living materials. Many inorganic fertilizers have nutrients that are immediately available to plants. Other fertilizers are formulated to allow nutrients to be released over some time. If you use an inorganic fertilizer in the landscape, select one with some or all of the nutrients in slow- or controlled-release form, so that the plants will be able to take up the fertilizer as it is slowly released.

Organic Fertilizers

Organic fertilizers are materials that are derived from plants; one of the most common forms is manure. The organic matter incorporated into the soil before planting will help fertilize vegetable plants, but you’ll need to add additional fertilizer after planting.

The quick availability of nutrients, especially nitrogen, is important in vegetable growing. Therefore, you could want to supplement any organic fertilizer you apply with some inorganic fertilizer for quick feeding. Many gardeners use a combination of fertilizers and methods in the garden. Gardeners who wish to avoid chemical fertilizers can use fish emulsions or manure teas. Fish emulsion, which is generally high in nitrogen but low in phosphorus, is mixed with water and sprinkled around plants every two to three weeks, or as needed. It normally has a 5-1-1 analysis. Manure tea is made by seeping manure in a tub of water. Place several shovelfuls of manure in a porous cloth sack, and then soak the sack of manure in the water until the water becomes the color of weak tea.

Easy household fertilizers

There are quite a few common items found in the kitchen, and elsewhere around the house, that can be used as plant fertilizer.

Aquarium Water

Water your garden plants with the aquarium water taken right out of the tank when cleaning it. Freshwater only please, does not use water from a saltwater tank. The fish waste makes a good plant fertilizer.


Bananas are not only tasty and healthy for humans, but they benefit many different plants. When planting rose plants, bury a banana in the hole alongside the rose. As the rose grows, bury bananas into the top layer of the soil. Both of these approaches will give the much-needed potassium that plants need for proper growth.

Blackstrap molasses

Blackstrap molasses is an excellent source of several different nutrients that plants use. This contains carbon, iron, sulfur, potash, calcium, manganese, potassium, copper, and magnesium. What makes this an excellent kind of fertilizer is that it feeds beneficial bacteria, which keep the soil and plants healthy. To use blackstrap molasses as fertilizer then mix it with another all-purpose fertilizer. A good combination to use is one cup of Epsom salts and one cup of alfalfa meal. Dissolve this combination in 4 gallons of water and top it off with one tablespoon of blackstrap molasses or simply mix blackstrap molasses in with compost tea. Do this after the compost tea has steeped.

Coffee grounds

Used coffee grounds have about 2% nitrogen, about a third of a percent of phosphoric acid, and varying amounts of potash (generally less than 1%). Coffee grounds are particularly helpful on those plants that like things a bit more acidic, such as blueberries, evergreens, azaleas, roses, camellias, avocados, and many fruit trees. Allow the coffee grounds to dry and scatter them lightly, as mulch, around plants. Avoid scattering them thickly when they are wet, as clumps of coffee grounds tend to get moldy.

You can also consider Growing Artichoke Hydroponically.

Cooking water

Several different nutrients are released into the water that food is cooked in. Water that is used to boil potatoes, several vegetables, eggs, and even pasta can be used as a fertilizer. Let the water cool before applying it to the soil.

Corn Gluten Meal

Corn gluten meal is a byproduct of the wet-milling method for corn. It is used not as an organic pre-emergent herbicide, but also as a fertilizer that is 10% nitrogen. To use as a fertilizer, basically spread a thin layer of corn gluten meal and scratch it into the top inch of soil. Plant veggie starts inside the treated area for optimum nitrogen benefit, and do not worry accidentally harming your plants. Corn gluten meal only works as an herbicide before seeds germinate, not after, so it won’t hurt plants that already sprouted.


Eggshells have about 1% nitrogen, about a half-percent phosphoric acid, and other trace elements that make them a practical fertilizer. Calcium is a necessary plant nutrient that plays a fundamental part in cell manufacture and growth. Most roots should have some calcium at the growing tips to grow effectively. Simply crush them, powder them in an old coffee grinder, and sprinkle them around garden soil.

Epsom salts

One tablespoon of Epsom salts can be combined with 1 gallon of water and put into a sprayer. Apply once a month and directly to the foliage, for a quick dose of magnesium and sulfur.


Gelatin can be a good nitrogen source. Dissolve 1 package of gelatin in one cup of hot water and then add 3 cups of cold water. Pour directly on the soil around plants once a month. This is good for houseplants.

Incase if you miss Hydroponic Greenhouse Farming.

Green Tea

A weak solution of green tea used to water plants every 4 weeks and use 1 teabag to 2 gallons of water.

Horse Feed

What makes horse feed irresistible to horses is what makes it an excellent fertilizer. To use horse feed as a fertilizer is easy and simple. It can be used as a soil amendment by sprinkling it on top of the soil. Alternatively, it can be dissolved in water alone or combined with another organic fertilizer, and also applied as a soil drench.

Powdered milk

Powdered milk is not only good for human consumption but also several plants. This source of calcium wants to be mixed into the soil before planting. Since the milk is in powder form, it is ready for use by plants.

Fertilizing house plants

Never try to equate fertilizing with feeding and plants get their energy from light, not fertilizers. Unless good light levels are supplied and the plant is growing well, fertilizing will do more harm than good. Newly purchased or repotted house plants must be given a few month’s rests from feeding so that they can use up the nutrients already present in their growing mix.

Plants require three main elements for healthy growth are nitrogen (N), phosphorus (P), and potassium (K). Fertilizers rich in nitrogen will stimulate healthy, green growth of foliage, while those rich in phosphorus will encourage root development and better flowering. Those rich in potassium will help build up reserves for several plants that have a dormant period.

A fertilizer labeled 30-20-20 would be good for leaf development and could be most recommended for foliage house plants. While flowering house plants could prefer one richer in phosphorus, such as 15-30-15. Most foliage house plants obtain along fine with a high-nitrogen fertilizer, while one with a high proportion of phosphorus is good for flowering house plants.

Ready-to-use liquid fertilizers are convenient, but expensive, while you pay for the water they contain. Water-soluble fertilizers, obtainable in powder or crystal forms, are just as efficient but are more economical because you add the water yourself.

Some people choose the practicality of slow-release fertilizers. These are obtainable in granule form to be mixed with the soil or in spikes and tablets that are pushed into the potting mix. They need to be applied once every few months.

That’s all folks about best fertilizers for plants, types of fertilziers and their application. You may also like the High Yield Vegetbale Crops.


Please enter your comment!
Please enter your name here