Water, the essence of life on Earth, plays an undeniably vital role in cultivating brilliant plants. The choices we make regarding the type of water used can significantly influence a plant's health, nutrient uptake, and overall yield. Understanding this watery realm and exploring the nuances of various water sources can be a levelling-up effort for some cultivators, so here we look at water types leading onto the modern marvel of reverse osmosis. Whether you are a beginner or someone who usually treats/deals with tap water, slap on a life jacket, inflate your dinghy and let’s jump into the deep waters of sourcing and treating your H20!
Sources of Water
Rainwater is to plants what make-up is to the Kardashians– essential to life! Falling, evaporated water is often free from many salts, minerals, and chemicals in other water sources. A notable aspect of rainwater is its lack of cleansing chemicals, such as chlorine or chloramine, commonly found in municipal sources. These chemicals, while crucial for purifying urban water supplies, can sometimes be detrimental to plants and the beneficial microbes dwelling in the soil serving the roots. Moreover, rainwater's naturally slightly acidic pH can be advantageous for nutrient absorption. However, in an area with significant pollution, rainwater can also be ‘unclean’ for human and plant consumption; therefore, filtering or treating rainwater before use might be a good idea.
Distilled water is a product of human ingenuity, essentially copying what nature does with the rain. Instead of natural evaporation, distilled water is achieved by boiling and condensing the steam into a liquid. So, like rainwater, distillation effectively rids the water of contaminants and minerals as these do not evaporate into steam; instead, they get left behind. While this purity is its strength, paradoxically, it could also be its weakness. Using distilled water consistently might strip the soil of essential minerals over time. Hence, if distilled water is your choice, ensuring the plants receive these vital minerals through other channels, such as feed and nutrients, becomes crucial.
Spring water, sourced directly from nature's underground reservoirs or hillsides, is another excellent source of water for plants. As the water journeys through the underground water systems, passing through various rock formations, it undergoes a natural filtration process, emerging relatively free from contaminants. However, the mineral profile of spring water is influenced by the types of rocks that filter it, and the outcomes can be as varied as the springs themselves. While many of these minerals are beneficial, it's wise to be aware of the specific makeup of the water at the spring to avoid any unintentional harm to plants.
Reverse osmosis water is a technological advancement in water purification. This process forces water through a semi-permeable (selective) membrane, resulting in a product almost entirely free of salts, minerals, and contaminants. This mechanism catches all the salts and minerals on one side of the membrane, and only pure water gets through to populate the other side. Much like the natural filtration of spring water, the RO process filters all the unwanted material from the water. But unlike spring water, no residual elements are leached from the rocks or, in this case, the membrane. For those aiming for precision in their cultivation practices, reverse osmosis provides unmatched control over the water's content. This way, growers can tailor their nutrient solutions meticulously, ensuring their plants get precisely what they need when they need it.
Advantages Of RO Water
Using reverse osmosis (RO) water to grow plants offers several advantages, especially in controlled environments like hydroponic systems or when tap water has many contaminants or additives, like heavy metals, chloramines, and other harmful chemicals that can be detrimental to plant health. Some plants are particularly sensitive to specific minerals or contaminants in tap water. Using RO water eliminates these concerns. Over time, using hard water (water high in minerals) can lead to salt/mineral buildup, harming plant roots and microbes and inhibiting growth. RO water helps prevent this buildup, promoting long-term root/soil health.
In soil, the pure nature of RO water can sometimes allow for better soil penetration and root absorption. With the reduction in harm to microbes, it has become more common for growers to use RO water when providing nutrients or feeds to plants in soil. Although some combinations of soil types and water types can be more harmonious than others, a crude example, for instance, slightly alkaline soil and somewhat acidic water, can result in a balanced pH for the plant roots.
For hydroponic systems or soilless mediums, RO water provides a "blank slate." This means growers can precisely add and control the amount and type of nutrients the plants receive. This ensures optimal nutrient uptake and avoids nutrient imbalances or toxicities. Many municipal water sources treat water with chlorine or chloramine to kill bacteria and other pathogens. While these are safe for humans, they can be harmful to plants, inhibiting the uptake of water and nutrients and potentially harming beneficial microbes in the soil. RO water removes these additives, leaving only pure water.
However, it's essential to note that while RO water removes harmful contaminants, it also eliminates beneficial minerals – again, depending on the source. If using RO water for plants, reintroducing some basic minerals (like calcium and magnesium) is often essential to ensure your plants get all the nutrients they need.
When To Use RO Water
Utilizing reverse osmosis (RO) water throughout the growing season offers specific benefits, especially during the crucial final two weeks before harvest, commonly known as the "flush." Despite its name, the flush isn't about flushing out built-up nutrients in the plant - this is impossible. Rather, it is about withholding nutrients and providing only water. RO water's purity is especially advantageous during this stage because of osmotic processes, potentially leading to a purer end product. While there are still unknown aspects surrounding the science of the flushing process, the primary idea is that water-only nourishment helps process the accumulated sugars from photosynthesis, resulting in fewer undesired compounds in the final yield. For those hesitant about adopting RO water for the entire growth cycle, a practical approach might be introducing it solely during the flushing phase to discern any qualitative differences in the harvest.
How Is RO Water Generated?
Reverse Osmosis (RO) is a water purification process that uses a semi-permeable membrane to remove ions, molecules, and larger particles from water. The Semi-permeable Membrane is a thin layer of material capable of separating substances when a driving force is applied across the membrane. It acts like an ultra-fine filter, allowing only small water molecules to pass through while blocking out larger substances, like salts, bacteria, and contaminants.
Osmosis is a natural phenomenon which allows water molecules to move from an area of low concentration to an area of high concentration through a semi-permeable membrane. With RO water, we're essentially "reversing" this natural process. We apply pressure to push water from an area of high concentration (like dirty water) through the membrane to an area of low concentration (clean water). This is why it's called "reverse" osmosis. The pressure is applied to overcome the natural or osmotic gradient.
Water on the "dirty" or "salty" side gets pushed through the membrane, leaving the contaminants behind so only pure water can pass through. The result is two separate pools; one is purified water (called the permeate), and the other contains concentrated contaminants (often referred to as brine or reject water).
Most RO systems include multiple stages of filtration. Before water hits the RO membrane, it typically passes through a sediment filter (to remove large particles like dirt) and a carbon filter (to remove chlorine and other chemicals that can damage the RO membrane).
After the RO stage, water may pass through another carbon filter to polish the water, making it more palatable and pure. The efficiency of RO systems varies, but they're generally effective at removing a wide variety of contaminants, including salts, sugars, proteins, particles, dyes, and bacteria.
Disadvantages Of RO Water
Using reverse osmosis (RO) water for home plant cultivation has advantages and pitfalls. While the purity of RO water offers unparalleled control over nutrient content, the high initial costs of quality RO units and their installation can be daunting, especially for hobbyists or those on tight budgets. The units themselves are expensive and may require professional installation. This could mean more pipes, digging up floorboards and more upheaval than expected.
Additionally, the efficiency of RO systems can lead to a significant rise in wastewater generation, raising environmental concerns, especially in water-scarce areas. This can also lead to increased ongoing costs due to larger monthly water bills. Finally, as mentioned above, stripping the water of all its minerals and salts can be dangerous if not balanced with the correct counter-dose of essential nutrients.
Conclusion
Although there is a high upfront expense and the potential for higher ongoing costs with larger water bills, RO water still offers more benefits than drawbacks. The precise control over the plants' feeding can result in a greater yield, cannabinoid production, and overall vigor of the plants. Learning the system correctly and the adjusted feed regime is essential, but doing this will undoubtedly help garner a more productive plant and better product quality.
