Liquid vs Granular Fertilizer [Pros and Cons] With Science

Wouldn’t it be great if you can just quickly choose the best liquid or granulated fertilizer? Unfortunately, there are so many fertilizer types, elements, and factors to consider that choosing one can be rather, well… daunting.

Liquid and granular fertilizers have different pros and cons to consider in terms of 1) your goals and limitations, 2) what your plants need, 3) what the soil lacks, as well as 4) the fertilizer type and nutrition content you should use for the best results.

Today, I’ll help you get to the bottom of it all and make choosing the right fertilizer much easier!

What are the Different Forms of Fertilizers?

The three main forms of fertilizer are 1) liquid, 2) dry, and 3) gas. In general, they differ in terms of speed of effect and method of application.

Few of us who use fertilizers actually know the key advantages and disadvantages of granular and liquid fertilizers. Of course, we know common generalizations such as these:

Type	Description
Liquid Fertilizer	These act faster than solid or granular fertilizers, and can be spread faster over larger areas such as farms and orchards.
Dry Fertilizer	These are organic or synthetic fertilizers that are produced en mass but require water for the plant to efficiently absorb its nutrients.
Gas Fertilizer	These are generally produced from natural gas such as methane which is processed to form nitrogen fertilizer.

What is Better? Liquid vs Dry Fertilizer

What are the Subtypes of Dry Fertilizers?

Subtypes of granular fertilizers include 1) cakes, 2) granules, 3) manure, 4) mulch or compost, 5) pellets, 6) powders, 7) sludge, and 8) spikes, sticks, or stakes.

Whether organic or synthetic, dry fertilizer gives different benefits. Here’s a quick rundown of dry fertilizer forms.

Forms of Granular Fertilizers	Description
Cakes	DIY as well as commercial fertilizers cakes are made to be ground or powdered for dilution and control. Examples are dung cake, oil cake, neem cake, mustard cake, sugarcane cake, and fermented cake fertilizer.
Granules	Commercial-grade fertilizers sold as concentrated dry granules are used for slow release. The granules are activated by water. PRO TIP: To prevent fertilizer burn, always wash away with water any granules left on the leaves.
Manure	Animal feces, either raw or dried dung collected from animals have been used for centuries to fertilize crop soils. It can smell but is eco-friendly.
Mulch or compost	Organic fertilizer can be in the form of mulch (spread on topsoil) or compost (mixed into the soil) which is deteriorated bio-materials from plants or animals.
Pellets	Commercial and DIY fertilizer is made in concentrated powder form for ease of sprinkling or mixing into soil or compost, as well as for water solubility in hydroponic or indoor use. Many manufacturers of powder fertilizer use synthetics such as phosphorus, calcium, magnesium, potassium, or silicon, or organics such as bone meal, fish, peat, neem seeds, or seaweed.
Powders	Municipal sludge from community sewage can be collected, dried, treated, and ground into biosolid compost for easy application as soil fertilizer.
Sludge	Municipal sludge from community sewage can be collected, dried, treated, and ground into biosolid compost for easy application as a soil fertilizer.
Spikes, sticks, or stakes	Commercial fertilizers in spike forms are designed for hammering into the ground and for slow nutrient release over 6 months. Before using, know how much fertilizer to use, and the type of fertilizer for specific plants.

Spikes of fertilizers are particularly interesting in terms of application. You need to hammer the spikes into soft, damp topsoil along the dripline for nutrient distribution and root contact when watered.

How to install fertilizer spikes & how they work.

What Fertilizer Should You Use?

The fertilizer one should use depends on the needs of the plant they are planning to feed. Leafy vegetables and foliage plants require nitrogen-rich fertilizers while flowering and fruiting fertilizers need

While mother nature doesn’t do labels, fertilizer manufacturers are required by law to inform buyers exactly what goes into their products.

Thus, each package shows an NPK code: three numbers that indicate the proportion of elements in the fertilizer.

Nitrogen (N) The first NPK number	Function: Nitrogen helps develop the parts of plants that you see aboveground, particularly the health of leaves. Deficiency: Your plant lacks nitrogen when the leaves are smaller than normal and many of the leaves are turning yellow.
Example 1	NPK 12.0.0: The fertilizer contains 12% nitrogen.  NPK 0.1.1: The fertilizer has 0% nitrogen, 1% P, and 1% K.
Phosphorus (P) The second NPK number	Function: Improves flowering, promotes seed formation, and induces the fruiting of plants. Deficiency: Phosphorus deficiency is not easy to spot. Some plants show purplish stems or dark blue-green leaves.
Example 2	NPK 1.9.1: The fertilizer has 1% N, 9% potash, and 1% K. NPK 7.8.9: A 100-pound bag of fertilizer has 7 pounds of nitrate, 8 pounds of phosphate (phosphorus), 9 pounds of potash (potassium), and 76 pounds of filler (also called ballast).
Potassium (K) The third NPK number	Function: Potassium makes plants resistant to pests and diseases as well as helps in root growth and development. It also facilitates the development of fruits. Deficiency: Potassium deficiency is not easy to spot. Some plants show purplish stems or dark blue-green leaves.
Example 3	NPK 12.10.20 fertilizer for tomato plants: One kilo includes 120 grams of N, 10 grams of P, and 20 grams of potassium. NPK 10.10.10 or 5.5.5: This is a fertilizer that provides the same relative amount of nutrients, so which one you use doesn’t matter. What you must know is how much fertilizer you should use, and when.
Minuscule quantities of Calcium (Ca), Sulfur (S), Iron (Fe), and Magnesium (Mg) in the soil are secondary but are key elements for chlorophyll as well as for plant growth and development.	Function: Potassium helps plants to develop buds, flowers to blossom, and fruits to grow0. Deficiency: Potassium deficiency in plants shows as stunted, discolored, and curled leaves, weak stems, and small fruits.

PRO TIP: When buying fertilizer from bulk sellers, write the NPK formula on your containers. Also, remember: that formula shows the percentage by weight.

Other countries have fertilizers with NPKS in their labels where S stands for sulfur.

More info on this in our article on plant nutrients!

Know Your Fertilizer: What NPK really means

What is a Granular Fertilizer?

About 90% of fertilizers are dry. Powders, pellets, granules, or cakes are put into the soil, but most are dissolved in water and then diluted before fertigation.

What are the Advantages and Disadvantages of Granular Fertilizer?

Since it’s clear that the well-being of our plants lies entirely in our hands, choose your fertilizer only after you have considered these common arguments for and against dry or granulated fertilizers.

Advantages of Granular Fertilizer

Disadvantages of Granular Fertilizer

Blending: Can be blended into specific types of fertilizer analysis. Application: Can be applied as broadcast or bands. With powders, there’s less chance of waste or spills. Timing: Nutrients are available throughout the growing season Cost: Cheaper when purchased in bulk. When ordering online, lighter weight means cheaper shipping. Storage: Will not settle or salt out when stored for long periods. Release control: Slow-release products (e.g., polymer-coated urea) available

Non-liquidity: Requires water for nutrients and minerals to be absorbed by plants Non-distribution: Less mobile elements (e.g., phosphorus) stay in the individual granules until accessed by plant roots. Rejection: Roots turn away from hot granules with too-high levels of potassium or nitrogen. Inconsistency: Nutrition or mineral content of each granule varies and cannot be assured.

FACTOID: For centuries, food crops in China and Japan grew on soil fertilized with human feces, the smell of which spread around agricultural provinces.

What is Liquid Fertilizer?

Liquid fertilizers can be natural concentrates or extracts, or they can be commercial products sold in agricultural stores as natural extracts, liquid concentrates, emulsions, or gels.

One advantage is that you can precisely control liquid fertilizers to provide a steady supply of nutrients. For instance, you can stop feeding dormant plants in winter or increase feeding for new growth.

The main disadvantages for small-scale home gardeners? You need to a) remember to do it every time, b) never go away on long trips, and c) you can’t use them for the slow release of nutrients.

What are the Subtypes of Liquid Fertilizers?

Subtypes of liquid fertilizers include 1) liquid concentrates, 2) natural extracts and concentrates, 3) liquid emulsions, and 4) gels. The best liquid fertilizer for plants will depend on the plant it will be applied to.

Liquid Fertilizers	Concentrated Liquid Fertilizers	Liquid Emulsion Fertilizers
Urine	Anhydrous liquid ammonia	Fish emulsion fertilizer
Compost extract	Ammoniates	Hydrolyzed fish liquid
Grass extract	Aqueous ammonia	Water-in-oil emulsion fertilizer
Seaweed extract	Ammonium nitrate and urea	Pinolene polymer emulsion
Mulch extract	Nitrogenous fertilizers	Soluble calcium emulsion
Chicken manure extract	Potassium, phosphorus, nitrogen calcium blends	Ammonium nitrate emulsion, suspension, or gel
Aquarium water	Urea	Emulsifiable concentrates

FACTOID: Colloidal clay and bentonite additives are used to prevent crystallization in liquid fertilizers during long storage.

What are Concentrated Liquid Fertilizers?

Concentrated liquid fertilizers dissolve and mix with water more rapidly than powders or other dry forms and therefore work more effectively. These are best for hydroponic plants.

What are Natural Extract Fertilizers?

Extracts or natural concentrates are a subtype of liquid fertilizers that are more concentrated through processes such as pressing and straining. Ideally, the excess water content must be removed, often by evaporation.

What are Emulsion Fertilizers?

Liquid emulsion fertilizers often come with complimentary A and B solutions. When the two solutions are combined, the nutrients and elements react with each other.

What are Gel Fertilizers?

Gel fertilizers such as liquid gel, starch gel, and seaweed gel combine the advantages of powder and liquid fertilizers. Slow-release gel fertilizers provide a high ratio of nitrogen, phosphorus, potassium, and other nutrients per liter of the product (yes, they’re completely water-soluble).

Advantages and Disadvantages of Liquid Fertilizers

Here’s a quick summary of the most common pros and cons of liquid fertilizers such as extracts, concentrates, emulsions, and gels.

Subtype of Liquid Fertilizer	Advantages of Liquid Fertilizers	Disadvantages of Liquid Fertilizers
Liquid Extract Fertilizer	Economical: Natural liquid fertilizer extracts can be diluted with water for more use per drop Safe: Natural extracts cannot burn or shock plants. There are no harmful chemicals or toxins. Ease of use: Natural fertilizer extracts can be easily applied by using either foliar or fertigation methods.	Time & effort: Creating natural liquid fertilizer extracts requires much time and effort for mixing, fermentation, pressing, and containing. Storage & preservation: Since they do not contain preservatives, natural liquid fertilizer extracts cannot be stored for a long time. They are best used when fresh. Content precision: There is no way to precisely measure or identify the nutrient or chemical content of natural liquid fertilizer extracts.
Concentrated Fertilizer	Strength control: Concentrates can be diluted with water for starter plants Consistency: Each drop contains the same amount of nutrition and minerals. Adaptability: Will blend with other products (e.g., for crop protection) Absorption: Nutrients are quickly absorbed by plants	Evaporation: Nutrients and minerals may evaporate along with the liquid. Drainage: Nutrients can be washed away by flowing water and can contaminate underground water sources. Storage: Will settle or salt out when stored for long periods. Water content means costlier shipping due to bulk and weight. Leakage is a concern.
Emulsion Fertilizer	Requires mixing: Emulsions are composed of two liquids that must be mixed to activate the fertilizing agent. Cost: Due to special production and packaging requirements, emulsion fertilizers can cost more than commercial fertilizers in liquid or dry forms.	Requires mixing: Emulsions are composed of two liquids that must be mixed together to activate the fertilizing agent. Cost: Due to special production and packaging requirements, emulsion fertilizers can cost more than commercial fertilizers in liquid or dry forms.
Gel Fertilizer	Handling: Gels are handled more easily than liquids; spills are recovered easier and faster. Slow-release: Gel fertilizers are particularly useful when you need fertilizers that slowly release nutrients. This means you can’t over-fertilize your plants. Conservation: Gel fertilizers do not allow volatile nutrients to be wasted through leaching or volatilization.	Unfamiliarity: Most soil fertilizer users are unfamiliar with gel fertilizer products and their proper applications. Cost: Due to specific production, packaging and container handling, requirements, gel fertilizers may cost more than liquid or dry commercial fertilizers. Leakage: Gel fertilizers can leak when containers are subjected to undue pressure.

What NPK Ratios are Used for Indoor Herbs?

Here’s a table of NPK ratios for indoor herb gardening.

Herbs	N (nitrogen)	P (phosphorus)	K (potassium)
Basil	10	10	10
Chives	5	10	5
Cilantro	24	8	6
Coriander	30	10	10
Lemongrass	20	10	10
Oregano	30	20	30
Parsley	30	10	20
Rosemary	12	12	17
Thyme	16	20	0
General fertilizers	8	8	8

You’ll find many resources online regarding recommended NPK ratios for lawn or yard grass, rooting purposes, and specific plants such as tomatoes and other garden vegetables.

Which is better: foliar spray or soil fertigation?

You can use liquid fertilizers either way. Here’s a summary of what you need to know.

Usage	Pros	Cons
Foliar spray	Application: Fertilizers are irrigated for ground absorption (via roots) Supplementation: Can supplement foliar-applied nutrients	Limitation: Rain, wind, heat, or pests limit effectiveness. Short availability: There is short-lived nutrient availability
Soil fertigation	Application: Fertilizers is irrigated for ground absorption (via roots) Supplementation: Can supplement foliar-applied nutrients	Escape: Nutrients can be carried away by water out of reach of plant roots.

PRO TIP: Since nutrient intake is higher when absorbed via roots (compared to the foliar spray) always dilute organic liquid fertilizer before fertigation.

FAQs

Summary of Liquid vs Granular Fertilizer

Fertilizers can be gaseous (not available commercially), liquid (including concentrates, emulsions, and gels), as well as solid (including powders, pellets, sticks, and cakes). Solid fertilizers can be slow-release or fast-acting.

Go for pelleted fertilizer if you buy it in bulk for more savings and easier storage and handling. Pellet fertilizer releases nutrients gradually over the growing season. Use liquid fertilizer for quick absorption of nutrients to correct the severe nutritional deficiency.

Organic fertilizers improve the soil and provide a slower distribution of NPK nutrients and micronutrients. Synthetic or chemical fertilizers feed plants quickly with specific ratios of NPK nutrients. Unfortunately, the need for constant replenishment is bad for the soil and the environment.

Sources

• “Fertigation: A Tool for Efficient Fertilizer” by U. Kafkafi and J. Tarchitzky in the Food and Agriculture Organization of the United Nations
• “The best way to use kinds of oil cakes as fertilizer” by n/a in Hang Xanh Company Limited
• “A History of Human Waste as Fertilizer” by Lina Zeldovich in JSTOR Daily
• “Liquid fertilizer for Plants will Help you Grow Bigger and Healthier” by n/a in Sierra Natural Science, Inc.
• “Fertilizer Types and Calculating Application Rates” by Rory Maguire, Mark Alley, and Webb Flowers in Virginia Tech
• “Horticultural fertigation – techniques, equipment and management” by n/a in the NSW Department of Industry
• “Fertilizing the Vegetable Garden – 7.611 arrow” by C.E. Swift and J. Self in Colorado State University

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