Figure 1. Cannabis in a healthy state.
Nutrients Needed By Plants; the N+P+K
Humans need nutrients in order to be healthy and productive. Plants are no different, indoor plants in particular need nutrients provided for them to produce their own food and develop well. While we do not want to write a chemical thesis or overwhelm anyone with detailed scientific data, we do want to provide an explanation of the basic chemistry that will help your plants grow and give you enough information to understand and decide on your nutrition plans and approach. If this seems like too much information/detail, then skip to the article “Cannabis Feeding Formula” and use the formulas presented in that article.
When we discuss nutrients we mean the materials that must be provided to plants for them to thrive, and we are talking about the 16 chemical elements known to be help plants grow. They can be categorized as either mineral nutrients or non-mineral nutrients. There are 3 non-mineral nutrients found in nature, namely hydrogen (H), oxygen (O), and carbon (C). Non-mineral nutrients are important in producing the energy that plants need through photosynthesis.
The other 13 chemical elements beneficial to plant growth are known as mineral nutrients. There are two types of mineral nutrients: micronutrients and macronutrients. Micronutrients are chemical elements that only need to be absorbed by plants in small quantities in order to encourage plant growth. Organic matter such as bark and fallen leaves are excellent sources of micronutrients. There are 7 known micronutrients in nature. They are boron (B), chloride (Cl), copper (Cu), iron (Fe), Manganese (Mn), molybdenum (Mo), and zinc (Zn).
Macronutrients, on the other hand, are elements that need to be absorbed by plants in larger quantities in order for them to be beneficial to plant growth. Macronutrients are further categorized into two groups; the primary nutrients, nitrogen (N), phosphorus (P), and potassium (K), and the secondary nutrients magnesium (Mg), sulfur (S), and calcium (Ca). Secondary nutrients are commonly found in substantial amounts in soil, as well as in decomposing organic matter.
The Primary Nutrients – Yes, it’s a tomato plant picture, almost identical to cannabis in soil, water, and nutrient requirements
Nitrogen naturally occurs in soil, water, and air. It is also found inside every living organism on the planet, in amino acids that make up proteins, in nucleic acids that build the hereditary materials inside living cells, and in many other organic and inorganic compounds. It is a chemical component of chlorophyll, which is the green pigment responsible for photosynthesis. Nitrogen helps plants grow faster and produce more fruits and seeds. In cannabis cultivation, nitrogen is an important component of many nutrient systems.
Another primary nutrient that is important for plant growth is phosphorus. It is one of the chemical elements that play a major role in the formation of starches and sugars through photosynthesis, and helps convert solar energy into chemical energy. Commonly absorbed from fertilizers, bone meal, and superphosphates, phosphorus encourages proper maturation, blooming, and root growth, and helps make plants more resilient to stress. In cannabis plants, high levels of phosphorus assist in the production of buds.
The third primary nutrient is potassium. Absorbed by plants in larger amounts than any other nutrient except nitrogen, potassium is responsible for building protein and distributing water throughout the different parts of the plant. It helps plants develop strong, thick stems, while also increasing their resistance to disease. Too much potassium in marijuana plants, however, results in the leaves exhibiting a yellowish or white streak in between the veins. Conversely, a potassium deficiency can cause your plants to grow smaller leaves with brown or tan edges, develop necrotic spots, and eventually die.
Acidity level of the Soil (pH Level)
Choosing the right type of soil can give you good and greener plants both indoors and outdoors. The availability of nutrients in the soil depends on the soil’s acidity level. Too much pH on your soil can lead to plant poisoning. On the other hand, low pH level serves as a hindrance to the nutrient intake of the plant and will also greatly affect the roots itself, consequently affecting the entire plant.
Maintaining the right pH level in soil is a crucial task, especially for indoor plants. Using potassium nitrate and calcium as fertilizers (when you already have natural alkaline soil) can acidify the soil while materials such as ammonium nitrate and ammonium sulphate push the pH level lower.
Growing Cannabis Indoor with Hydroponic
A common misconception about growing cannabis includes the myth that growing indoors must be associated with a complete hydroponic system: a technique for growing plants without soil. However, this is not always the case. A simple grow light system in a conducive indoor environment is already enough. Simply put, having the best media, nutrients, and grow lights is the key to an effective cannabis development.
Studies and researches on plant metabolism have proven that plants get their nutrients in the form of simple organic ions. The soil is the primary source that delivers water-soluble nutrients which the plants absorb. When using soilless media it is important that the nutrients be delivered through the media to the plants for them to florish. We recommend using a modified “Lucas Formula” mix of the General Hydroponics nutrient system, which is discussed in our article “Cannabis Feeding Formula”.