Growing consistent, high-quality cannabis at scale has evolved from an art to a science. The mysteries of “too much or too little” have essentially all been solved, giving growers who invest in precision a competitive edge. Modern nutrient formulas require a base of purified water for mixing, as they use pure water to calibrate and measure formulation.
In this article, we take a hard look at the top ten compounds found in water that need strict regulation for consistently optimal growth. Too much or too little can severely damage a crop, and should an operation go live without fully understanding the chemicals involved, the results could be disastrous.
While boron toxicity isn’t particularly common, when in excess, it happens to be one of the most expensive compounds to remove from source water. Small amounts of boron are critical for healthy stems, leaves and roots. However, at levels over 0.5 ppm, boron causes leaves to yellow and drop. Water with excess boron is typically related to past or active underground volcanic activity.
Calcium is one of the most important nutrients for a healthy cannabis plant. However, the carbonate form of calcium commonly found in tap/well water, is a much larger molecule than calcium used in nutrient formulas. The larger version can inhibit root uptake, delivering too little calcium and resulting in a stunted, slow to mature plant. Too much calcium can act the same way, monopolizing root pores creating deficiencies in potassium, magnesium and manganese.
Just like in humans, iron is a necessary nutrient for proper metabolic function in plants. Too little iron results in smaller plants, buds, and lower weight yields. Leaves develop interveinal chlorosis, a condition where the vascular tissue in a leaf remains green but the rest turns yellow. Too much iron in source water is characterized by brown leaves with even darker spots.
Magnesium is what makes green plants green, as it is the center of the chlorophyll molecule. Too much magnesium, aside from creating very dark green leaves, inhibits plant growth and can result in lower yields. Too little magnesium can be hard to identify as symptoms do not immediately appear, typically. When they do, the plant will become sick, with yellowing and brown spots on the leaves.
Manganese is a trace element that supports several basic but important functions critical to plant health. Interestingly, manganese also protects roots by creating root zones that are less hospitable to unnecessary or harmful microbes. Too much manganese can appear as tissue damage to new growth. Too little manganese shows up as yellowing leaves with brown spots, leaf drop and plant death.
Nitrogen is essential for the main growth function of cannabis, photosynthesis. When properly calibrated, nitrogen makes healthy babies and robust mothers. Too much nitrogen causes weakness across the plant, especially in the stems. Too little nitrogen is a primary cause of low yield and low potency. Cannabis low in nitrogen typically turns yellow.
Like nitrogen, phosphorus is essential for plant photosynthesis and growth. In fact, plants deficient in phosphorus can present coloration symptoms like purple stems and blue-ish leaves. Usually, this is an indication of a weak plant that easily succumbs to pests and disease. Too much phosphorus blocks micronutrient uptake leading to several deficiencies; leaves grow thin and burn at the tips.
Out of all the different chemical compounds that are both needed but can also be toxic, potassium is the one most responsible for water uptake and distribution through the plant. Consequently, it is primarily responsible for delivering energy where the plant needs it most, in the form of sugars and carbohydrates. Plants low in potassium show leaf burn symptoms and produce smaller, weaker flowers. Too much potassium results in burnt, damaged roots and numerous micronutrient uptake deficiencies.
Among the many outcomes of having a proper amount of sulfur uptake is higher quality oils and terpenes. Low sulfur typically results in unhealthy buds, weak in potency and volume. Excess sulfur can result in smaller plants and lower yields.
Zinc is only required in trace quantities but is important for chlorophyll production and healthy plant tissue. In great excess, zinc poisoning can interfere with iron uptake and kill plants quickly. Plants lacking in zinc will show symptoms like smaller buds, burnt leaves and smaller yields.