Let me preface what I am about to say with this: I am not an expert in cannabis, nor do I try to be. However, I am an expert in water treatment and cannabis does require water to grow. In fact, there is no cannabis without H2O. This happens to be my 50th year in water treatment. I have always been involved in agricultural water treatment since my very first year in the business, but in the last five to six years, water treatment for agriculture has declined compared to water treatment for Cannabis or Marijuana and Hemp. Just a couple of years ago the Number One Vertical Market at US Water Systems was craft beer brewing. We dominate that market and have for years. We are proud of the fact that no one has provided more water treatment systems for craft beer brewing than US Water Systems in the USA.

However, for the first time, in 2021, craft beer brewing and distilled spirits were no longer our Number One Vertical. That vertical is now Number Two. Cannabis, almost seemingly overnight, surged to the Pole Position and it looks like it will stay that way for quite some time. It was surprising to me that water for cannabis would surpass Water For Craft Beer Brewing and Distilled Spirits, Laboratory and Deionized Water and Water for Agriculture, but it happened and we decided that if we could do it accidentally, we could do it on purpose, so 2022 marks the first year that US Water Systems has exhibited at a Cannabis Trade Show.

Before I continue, it is widely established that water is the key component of any agricultural endeavor, as no plant can grow without water. Therefore, proper water treatment and pure water is also vitally important to ensure that any plant is fit for human consumption as well as meeting various regulatory standards. This is especially true for the cannabis industry. Given its meteoric growth in the United States—with medical marijuana now legal in most states and recreational marijuana legal in a growing-number of states—the cannabis industry is showing no signs of slowing down.

To All Growers

If you are looking to join the cannabis industry as a grower, it is vitally important that appropriate care be given in order to produce a crop that outshines the competition. In the cannabis industry, where growers aim to produce a refined, boutique-quality product, water quality and other specialized growing practices are especially important. This article focuses on the water side of that equation.

Too often we see water treated as an afterthought. All the focus is on the facility, energy usage, lighting, seeds, cultivation practices and drying, but the single most important ingredient required for growing cannabis is neglected. It becomes an “afterthought” and plenty of growers have learned this the “hard way.”

Several years ago, Marijuana Venture: The Journal of Professional Cannabis Growers and Retailers published this:

It's the challenge on every expanding grower's mind: how to reliably scale premium, boutique cannabis to commercial volume. The answers are complicated and, to a large extent, highlight the struggle most small- to medium-sized growers face as they branch out to the big time. And many expanding businesses overlook a basic, fundamental element that can leverage the success or failure of a growing company: water.

Water as a monitored input is almost unheard of in typical commercial agriculture operations. After all, the goal of industrial farms is typically volume, not quality. As big players from traditional agriculture step in to mentor the emerging cannabis industry, serious caution should be taken, as irrigation methods that have worked for decades with other crops simply do not apply to cannabis. As a matter of fact, many of these methods can actually inhibit proper growth, undermining an otherwise perfectly engineered operation, because of water chemistry's effect on nutrient bioavailability.

Tap and well water, though plentiful and cheap, are typically high in total dissolved solids (TDS), particularly magnesium and calcium carbonates. On the surface, this might actually sound like a benefit — after all, plants need calcium for healthy connective tissue and magnesium for robust photosynthesis, right? Absolutely true. However, it's the carbonate form of these compounds and their large molecular weight that's the problem. The molecule size is simply too large to be absorbed by the plant at an optimal rate. Regardless of how dialed-in nutrient formulas might be, there's no overcoming sluggish nutrient uptake due to clogged root pores, commonly referred to as “nutrient lockout.” The solution requires two steps: strip everything out and then add back what is necessary for optimal plant nutrition.

The most cost-effective way to generate pure, low-TDS water at a large volume is commercial reverse osmosis. The largest, top-shelf cannabis growers in the world use this method, creating a massive, pure-water nutrient formula base, at a volume of up to 1 million gallons a day. Since every location's water will have a unique chemical profile, these systems must be custom built. But the return on investment for these systems — typically a fraction of overall buildout costs — comes quickly once the results are realized.

Using reverse osmosis for growing cannabis is nothing new. The process of osmosis using a semipermeable membrane was discovered in a laboratory in 1748 by Jean-Antoine Nollet. He used a pig's bladder as a membrane, and proved that a solvent could pass selectively through a semi-permeable membrane using that process.

However, Reverse Osmosis occurs when you apply a pressure in excess of the osmotic pressure against a semipermeable membrane, and it was not until 1949 that the University of California at Los Angeles attempted to remove salt from seawater using this process. In the mid-1950s, both the University of California and the University of Florida researchers began to produce fresh water from seawater… and so it started.

In the early 1960s, Donald Bray, started Desalination Systems, Inc., and Nimbus Water Systems, Inc. He patented the first commercial spiral-wound RO membrane configuration. He and several of his colleagues were responsible for many RO patents and innovations, including the first commercial/residential RO system, the first multi-layer RO membranes, and new membrane manufacturing techniques. I bought my first Reverse Osmosis System from Don Bray in 1982, not knowing that someday I would help found a company that would be one of the major players in manufacturing reverse osmosis systems.

Water Quality for Improved Product Quality

There are many “best practices” when it comes to growing cannabis successfully and profitably. However, we are here to discuss what growers can do to increase their yields and profitability by growing cannabis with high quality water.

As I mentioned earlier, water is frequently overlooked as a critical component of growing cannabis. After all, many people feel that if water is safe to drink, it must be safe for growing plants. Before we can decide how to treat the water, we must first understand the role that water plays in growing any plant, and especially cannabis. Cannabis is approximately ninety percent (90%) water, so it would be difficult to overstate the important role water serves in growing the plant.

I can't write it any better than the Royal Queen Seeds Blog, so here is how they phrased it:

“Water transports nutrients, gives the plant its stiffness and lushness or "turgor," and plays a major part in photosynthesis. During the day, water travels up the stem to the leaves where it evaporates through tiny holes called stomata and is then exchanged for carbon dioxide. This is called transpiration. The exchanged carbon dioxide is then used to in combination with light to create sugars which are the plant's food; this is called photosynthesis.”

Poor water quality means that these natural processes may be impeded greatly or even stopped altogether which greatly affects the production, and ultimately impacts the bottom-line profitability. While marijuana grows without treated water in many places, those looking to cultivate a high-quality, thriving crop for commercial purposes will want to use treated water. Untreated water can contain chemicals and minerals that can stunt plant growth even in small concentrations.

An example is calcium and magnesium, which are commonly found in hard tap water. Calcium and magnesium can benefit plants as nutrients at the correct levels, but too much can be detrimental to plant growth. Other chemicals like chlorine and bacteria can have adverse effects. Cannabis growers also have to take into consideration the pH and temperature of the water.

Untreated water can also have cations and anions that can hinder the growth of the plant. To remove these chemicals and salts and get water to the right composition for proper cannabis growth, reverse osmosis (RO) is really the only economical and sustainable process. Growers can use RO-treated water as a base before adding in the right nutrients for their crop. Calcium and magnesium at the correct levels and broken down to the right size for plant uptake are often added, along with other nutrients like nitrogen and potassium.

Ultimately, water quality is a key concern for marijuana growers using soil and hydroponic methods alike. With consistent water quality, cultivators can get the most out of their crop and produce a high-quality, commercially viable product. Without treating their water appropriately, growers may see variations in their yield and find they need to take time and effort to diagnose the cause. Proper treatment means growers can eliminate water as a factor when harvest issues arise.

As the marijuana industry continues to grow in the U.S., successful cannabis producers are paying close attention to controlling conditions including lighting, humidity, soil quality, and air circulation— water treatment is just one piece (albeit a HUGE piece) of the puzzle.

What a Cannabis Water Treatment System Looks Like

As I mentioned earlier, a reverse osmosis system is a vital piece to the cannabis growing puzzle. I could argue that it is the most vital piece, because no one leaf of cannabis can be grown without water. The importance of water to successful cannabis growing cannot be ignored or over estimated. I believe the science of treating water for cannabis is settled. Reverse osmosis is unquestionably the best method for treating water that is used for growing cannabis. Reverse osmosis removes the widest spectrum of contaminants of any water treatment process and typically produces water with a pH that is slightly acidic, although after sitting in a storage tank for a period of time it becomes neutral.

However, a reverse osmosis system is actually a whole lot more than just the reverse osmosis process. A sustainable and economical system utilizing reverse osmosis utilizes several other technologies including (but not limited to) Oxidation, Filtration, Absorption, and Disinfection (including ultraviolet, quantum, and ozone).

The Importance of Water Testing

A grower should NEVER, EVER, EVER, NEVER plan a cannabis growing facility without a good detailed Laboratory Water Analysis from an accredited Laboratory. US Water Systems provides a Laboratory Test which we recommend to all growers. You don't have to buy it from us, but you probably won't find it at a lower price. Water Testing is not a profit center for us. We offer it as a convenience. We buy in bulk and pass the savings on to you.