Hydroponics is a cultivation technique that replaces the traditional soil medium with a solution of water and mineral nutrients delivered directly to the plant roots. By eliminating soil, growers gain precise control over the plant’s environment, allowing for optimized growth cycles and resource efficiency. This approach is used for cultivating various plants, including cannabis.
Hydroponics: The Science of Growing in Water
Growing plants in a soilless system requires a fundamental shift in how the roots receive necessary elements. Instead of spreading through dirt to seek out moisture and nutrients, roots are suspended directly in a dynamic, oxygen-rich environment. This allows the plant to focus its energy on upward growth rather than developing an extensive root structure.
One common water-based system is Deep Water Culture (DWC), where the roots are fully submerged in a reservoir of nutrient solution. Plants are held in place by net pots filled with an inert medium like clay pebbles. Because the roots are constantly underwater, the solution must be heavily oxygenated to prevent drowning and root rot.
Aeration is achieved using an air pump connected to air stones, which constantly bubble oxygen into the reservoir. This continuous oxygen supply ensures the roots can respire while simultaneously absorbing water and nutrients.
The Nutrient Film Technique (NFT) is another popular method. In this setup, a thin film of nutrient solution flows continuously over the roots, which are housed in a slightly sloped channel. The thinness of the film ensures that part of the root mass is exposed to the air above the water line, providing necessary oxygen. This system relies on a pump to constantly recirculate the solution from a reservoir up to the channels and back down via gravity.
Essential Nutrient Management
Removing the soil means losing its natural ability to buffer changes in chemistry, shifting the responsibility for nutrient delivery entirely to the grower. The nutrient solution must be meticulously measured and maintained to ensure plants have access to all necessary elements. The two most important parameters to monitor are pH and Electrical Conductivity (EC).
The pH level, which measures the acidity or alkalinity of the water, dictates nutrient availability. Cannabis plants absorb nutrients most efficiently when the solution is slightly acidic, typically maintained between 5.8 and 6.2. If the pH drifts too high or too low, certain nutrients will chemically bind and become “locked out,” making them inaccessible to the roots.
Electrical Conductivity (EC) or Parts Per Million (PPM) measures the total concentration of dissolved mineral salts (nutrients) in the water. An EC meter provides a reading that indicates the strength of the nutrient solution. For instance, a young seedling may require a low EC of 0.8 to 1.2 mS/cm, equivalent to a PPM of 400 to 600.
As the plant matures into the vegetative phase, its nutrient demands increase, requiring a higher EC, often in the range of 1.2 to 1.8 mS/cm. The flowering stage sees the highest demand, with EC levels often peaking between 1.8 and 2.5 mS/cm, before being reduced near harvest time. Constant monitoring of EC ensures the plant is not underfed, leading to deficiencies, or overfed, which can cause nutrient burn and damage the sensitive roots.
Water vs. Soil: Key Differences in Cultivation
The choice between water and soil cultivation methods results in fundamentally different growing experiences and plant outcomes. Hydroponics offers a significant advantage in growth rate and overall yield due to the direct, constant access to nutrients and oxygen. Since the roots do not expend energy searching for food, the plant can channel that energy directly into developing foliage and flowers.
A soil medium acts as a natural buffer, absorbing and slowly releasing nutrients, which makes the system much more forgiving of minor errors in feeding or watering. Conversely, hydroponics is a high-precision method that requires greater technical input and attention to detail. Growers must perform daily pH and EC checks and execute complete reservoir changes approximately every one to two weeks.
While soil cultivation may require more frequent, smaller watering adjustments, hydroponics demands rigorous, technical monitoring of the solution chemistry. This intense control is a double-edged sword, as a hydroponic system is less forgiving of mistakes. A sudden failure in the air pump, for example, can rapidly lead to root suffocation, or a pH crash can cause widespread nutrient lockouts in a matter of hours.
The higher potential for faster growth and larger yields in hydroponics is balanced by the increased vulnerability to system failures and the necessity for a steep learning curve. Soil provides a more stable, buffered environment that is easier for beginners, while water-based growing offers maximum control for experienced cultivators willing to manage the technical complexities.