By Tate Dooley

In today’s market of legalization, margins on end-products are coming down. This means that growers have to cut costs in any area possible. One of the largest recurring hard expenses is fertilizer. Most growers also realize that the quality of their fertilizer can dictate the quality of their plants and the yield they reap. However, a lot of high-quality fertilizers (powder or liquid) in the industry currently are just too expensive on a commercial scale. In seeking out the magical unicorn of perfection–quality vs. cheapness–where is the perfect balance? If you look at some of the cheapest fertilizers on the market, they are often petroleum-derived and contain many heavy metals and compounds that are very bad for plants, people, and the planet. This leads to high amounts of phosphate runoff and algae bloom, which is toxifying our lakes rivers and streams. Petroleum-based chelates and synthetics have already been proven by the scientific community to negatively effect our environment, atmosphere, and economy. We need to switch to a commercially efficient and tunable carbon-based solution.

Due to recent technological developments, it is much easier to apply organic nutrients much like you would traditionally apply synthetics.

The answer to a mass adoption of organics was not only in making the cost of operation more affordable to achieve a higher profit margin. For commercial growers, the real trick is to make the products able to run in their systems and fall under the traditional “set it and forget it” hydroponic mindset. This would also mean that large amounts of sediment left in the bottom of reservoirs would be a no-no. Traditional organics, unfortunately, fails in most of these basic areas of agriculture.

Traditional agriculture uses predominantly soilless media, drip systems, fertigation systems, inline water treatment and filtration systems, and pressure-compensating drip emitters. Traditional organics does not work in these systems because of the nature of clumpy and chunky non-soluble powders, and thick liquids that leave behind a lot of sediment and cause bio-slime. We now have the technology to make our powders more easily soluble and even use technology to do fun things like nanoparticle enzymatic encapsulation.

We could tell a large-scale commercial cultivation facility, “the only way that you are going to be able to do 100-percent organic cultivation is by completely switching over media, potting systems and size, incorporate composting, top dressing, cover crop, spike layer and zoning into media, and even need to learn how to monitor bacterial versus fungal populations, beneficial nematode population, ciliate vs. flagellate and general soil health.” But, this simply is not feasible when you start talking about hundreds of thousands of square feet of warehouse and acres of greenhouse. They need to have cost-effective, easy to run products that allow them the maximum control for what their plants specifically need. Choosing the right fertilizer for their crop is the first step in this. 

Concentration

Most liquid fertilizers are made up of powder and granular ingredients that are simply watered down. When it comes to fertilizer, if you want the most cost-effective products with the highest amount of control and concentration, powder and granular fertilizers have many advantages over liquid. 

First, higher concentration and higher percentage of active ingredients is the name of the game with powders and granular fertilizers. Depending on the extraction methods, this can yield concentrations of up to 99-percent active ingredient. How does this affect you as a cultivator? Well, effectively, it means you need less product to cover a larger volume of treated water or plants. Depending on the cost of that fertilizer, this should lead you toward a lower fertilizer cost per gallon.

The higher concentration of active ingredient, the lower my cost should be then, right? Well, no. Unfortunately, some manufacturers that realize that they have a high-quality product and a high concentration, are not able to scale production quickly enough, don’t have access to enough material, don’t have an efficient enough manufacturing, packaging, or logistics process, or many other things that can contribute to costs associated with a product that simply is not commercially affordable. Concentration percentage and the type of active ingredient being extracted go hand-in-hand. For me, this is one of the most fun areas to monitor in this industry. People are always finding new ingredients, new extraction technologies, and new processes to make them available to plants.

Versatility

Powdered products can be used in a much more versatile manner than liquid products. They can be used in soil amending, top-dressing, reservoir applications, compost teas, spike layer solutions, and zoning. Liquid products have a much less versatile usage, best used via liquid applications such as root drenching and foliar feeding.

Shelf life

Think about where most products come from. Most are stored in a warehouse that is typically not temperature controlled and shipped in trucks with the same characteristics. This all means a lot of uncontrolled environments and, as it is one of the best temperature conductors, liquid heats up very easily. During transportation and storage, the temperatures most liquid fertilizers need to be kept at are not respected. This dramatically reduces a product’s shelf life. This shelf life may not be accurate even to what is printed on the bottle. Furthermore, I see a lot of growers storing their nutrients in direct light, heat, and, often, without a proper cap or lid. Once the shelf life of a product is being pushed, you can have irregularities in the manufacturer’s formulation for its intended purpose and your plants can start turning yellow.

The shelf life of powder is much easier to control, as powders do not need preservative fillers or stabilizers to keep the product evenly mixed and suspended, and they do not conduct temperature as easily as liquid, the shelf life is extended dramatically. Often, powders and granular products have an unlimited shelf life, as long as you store the product correctly (with the exception of biologicals, which usually have about a two-year shelf life). 

The only thing that can dramatically affect the shelf life of powders is exposure to liquid. It is best to keep them up off the floor in a dark, dry room. Powder pro tip: keep your bulk bags in a storage area and use smaller containers or even Tupperware to have your weekly supply on hand. This will eliminate cross-contamination, water spillage, and anything else from happening to your bulk bags of powder.

Carbon footprint and sustainability

Think about how large the carbon footprint is behind the average bottle of hydroponic liquid fertilizer. Often, these manufacturers buy water in bulk by the truckload. This means the water that they are going to add their powders into to create a stock solution is being shipped to them. Then, they add energy via heat to the water and powder to get them to solubilize and suspend together. Then, there is energy used to store that product in the manufacturer’s warehouse for a short amount of time. Then, there is energy used in the transportation process taking it from the manufacturer’s facility to the distribution facility. Then, there is energy expended taking it from the distribution facility to the retail facility. Then, you as a consumer expend energy to drive to the retail store to pick it up. How many chains of shipping, handling, and carbon footprint do we have behind one product? A lot! 

The container products come in is also important to consider. Did you know that the US throws away 60 million plastic water bottles per day? We are literally killing the planet with single-use water bottles and non-biodegradable packaging. The hydroponic industry is no different. When you walk into a hydroponic store, bottles are all you see. Sometimes, these bottles get used within a week of being opened. I have yet to meet more than a small amount of growers who actually reuse these bottles or who actually recycle these bottles of fertilizer when they are spent. Think about the amount of waste and petroleum-based containers that just the hydroponic and agriculture industry is producing! Then think about all of the petroleum that is used to transport all of those products to the stores. Then, think of the amount of petroleum that you use to get that bottle from the store!

Solubility

This is the one area most liquids have most powders beat. Aside from precipitants, which can be insoluble after mixing into your reservoir solution, liquid nutrients are in a solubilized state already. So there isn’t much argument there. However, we’ve all seen other liquids that leave behind sediment and sludge in your reservoirs and are quite thick in the bottle. We have to applaud these manufacturers’ attempts to increase the concentration levels of these products. This is typical in organics, where they are more of a sludge consistency in concentration form. Hey, at least it’s not 100-percent water, right? As far as powders go, in the market, there are definitely powders that are very difficult to solubilize and, instead, end up suspended in your solution when left for a long period of time without agitation or aeration.

Control

Powders have the most control. Usually, when you buy powdered fertilizer, you are buying either a blend or the ingredients individually. If you have an agronomist onsite, access to a consultant, or are a super mega genius scientist you can fine tune and control each individual ingredient of your nutrient formulation specifically for what your plants need. We would want to do this because, as growers know, there is never one variable in the garden that changes on its own. Everything must be tweaked accordingly. This goes for individual nutrients and their ratio in relationship to other nutrients. Buying amino acid, humic acid, and phosphorus all separately has huge benefits. When you can control your nutrient formula and environment in symbiotic relationship to one another, you can dial in your grow to achieve the best cost efficiencies and production.

Timing

Most often, the finer the powder, the faster it mixes and the faster your plants can consume it. Nowadays, there are a lot of micronized products on the market. This is truly amazing to see because of the high expense to manufacture these products. The really cool part is all the different technologies that are being pushed on top of the micronized process. Some of these processes allow nutrients to homogenize better into a solution, solubilize faster, be taken up faster by plants, and even better work with the biology. A lot of processes in a carbon-based system require biology to break down the nutrient to feed it to the plant. The size of these particles dictates the length of time required for the amount of biology that you have available in your system to break down that nutrient. This is why people are looking for the highest amount of bacteria and species in their inoculants and soil as possible. The higher amount of bacteria in your soil, the faster the nutrients become available, but the really fun thing is that the plant is also sweating out of its roots. The sweat is called an exudation. In a true carbon-based, true living system, your plants exudations are food for the microbes and the microbe’s exudations are food for the plants–it’s a closed-loop system.

It’s important to know that true living systems do not require a lot of input. They should be what I just said: a closed loop system. However, in container gardening, with the high demands we put on cultivation these days, you will need some type of input to be able to achieve maximum results. Traditional organics require a good deal of time to break down. Some rock dusts and other minerals can take anywhere from one to six months before they become available, depending on the amount of biology in your soil. If your planet is only in that soil for 90 days, then you could potentially be wasting money or just calculating the timing of your nutrient availability incorrectly. I am a firm believer in putting your slow breakdown nutrients in a light to medium volume in your soil every time you use it (if you are mixing soil), and feeding micronized carbon-based nutrients through your drip system, which will breakdown quickly and be available to your plans sooner.

Where do liquids come from?

Most liquid fertilizers start as powders and granulars. Using heating, cooling, and other processes, manufacturers are able to solubilize higher amounts of ingredients per volume of water to attain a higher concentration. The problem is, once you achieve a certain concentration, you have what is called “fallout.” A lot of hydroponic fertilizers on the market have fallout already occurring when you buy it off of the shelf. If you’ve ever gotten a liquid fertilizer with clumps and chunks in it already, this is the case. The problem is, once you have precipitants falling out of solution, the formulation of fertilizer is incomplete or missing pieces of what it once was. Most of the time, these precipitants are quite difficult to solubilize unless put back through additional heating and cooling processes. Manufacturers are concentrating their liquids to this extent to try to get a higher concentration. 

THE CHOICE IS YOURS

   What experienced growers have come to find, and newer growers will learn through trial-and-error is that, ultimately there is a time or purpose for which powder is the better choice and a time or purpose for which liquid is the better choice.  It doesn’t necessarily have to be one or the other and most gardeners I know use a combination of the two.  Hopefully, with each passing growing season, you’ll get better at identifying the better choice for your own garden’s ever-evolving acute and longer-term needs.  

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