Penn State University- Department of Agricultural Science has a great article on the essential nutrients for healthy plant growth. It is written for hydroponic systems which is not the focus of Greenbridge's products but there is still great information to help you.
Let's summarize their work on a few key points and then I'll provide some ideas for how to you can monitor and provide nutrients to your plants.
Plants, like any living organisms, require a balanced diet to flourish. This diet consists of 17 essential nutrients that serve as the building blocks for growth and development. These nutrients can be broadly categorized into macronutrients and micronutrients, each playing a unique role in the plant's health.
| Nutrient | Approximate content of plant (% dry weight) | Roles in plant | Source of nutrient available to plant |
| Carbon (C), hydrogen (H), oxygen (O) | 90+% | Components of organic compounds | Carbon dioxide (CO2) and water (H2O) |
| Nitrogen (N) | 2–4% | Component of amino acids, proteins, coenzymes, nucleic acids | Nitrate (NO3-) and ammonium (NH4+) |
| Sulfur (S) | 0.50% | Component of sulfur amino acids, proteins, coenzyme A | Sulfate (SO4-) |
| Phosphorus (P) | 0.40% | ATP, NADP intermediates of metabolism, membrane phospholipids, nucleic acids | Dihydrogen phosphate (H2PO4-), Hydrogen phosphate (HPO42-) |
| Potassium (K) | 2.00% | Enzyme activation, turgor, osmotic regulation | Potassium (K+) |
| Calcium (Ca) | 1.50% | Enzyme activation, signal transduction, cell structure | Calcium (Ca2+) |
| Magnesium (Mg) | 0.40% | Enzyme activation, component of chlorophyll | Magnesium (Mg2+) |
| Manganese (Mn) | 0.02% | Enzyme activation, essential for water splitting | Manganese (Mn2+) |
| Iron (Fe) | 0.02% | Redox changes, photosynthesis, respiration | Iron (Fe2+) |
| Molybdenum (Mo) | 0.00% | Redox changes, nitrate reduction | Molybdate (MoO42-) |
| Copper (Cu) | 0.00% | Redox changes, photosynthesis, respiration | Copper (Cu2+) |
| Zinc (Zn) | 0.00% | Enzyme cofactor-activator | Zinc (Zn2+) |
| Boron (Bo) | 0.01% | Membrane activity, cell division | Borate (BO3-) |
| Chlorine (Cl) | 0.1- 2.0% | Charge balance, water splitting | Chlorine (Cl-) |
| Nickel (Ni) | 0.000005-0.0005% | Component of some enzymes, biological nitrogen fixation, nitrogen metabolism | Nickel (Ni2+) |
Macronutrients
Including carbon, hydrogen, oxygen, nitrogen, phosphorus, potassium, sulfur, calcium, and magnesium, are required in relatively larger quantities. These nutrients contribute to various aspects of plant life, from structural integrity to energy production.
Micronutrients
Such as iron, manganese, zinc, boron, molybdenum, copper, and nickel, are equally vital, albeit in smaller quantities, for enzymatic reactions and overall metabolic processes.
**pH: The Balancing Act for Nutrient Availability**
Achieving the right pH balance is crucial. pH, a measure of acidity or alkalinity, directly affects the availability of nutrients to plants. The optimal pH range for hydroponic vegetable growth usually falls between 5.0 and 7.0, a slightly acidic to neutral environment. This range ensures maximum nutrient uptake and utilization.
The relationship between pH and nutrient availability is graphically depicted in the pH-nutrient availability chart. The chart illustrates how different pH levels influence the relative availability of nutrients. Nutrient uptake is most efficient when pH is within the sweet spot for each nutrient, highlighting the delicate balance that hydroponic cultivators must maintain.
A great option for monitoring your overall pH level of your soil or water is with alkaline strips or a digital pH meter.
**Nutrient Antagonism: Needing Equilibrium**
Maintaining nutrient balance is not as straightforward as providing an ample supply of each essential element. Plant uptake of essential nutrients can experience "nutrient antagonism". This phenomenon is when an excess of one nutrient interferes with the uptake of another, leading to unforeseen deficiencies. For instance, an excess of potassium might hinder the absorption of nitrogen, even if adequate nitrogen levels are present in the nutrient solution.
Regular monitoring of nutrient levels, coupled with a keen awareness of potential antagonisms, allows growers to fine-tune their nutrient solutions and prevent deficiencies.
Agribio Systems has a useful chart to help show the relationship between each nutrient. The chart is known as a Mulders Chart.
The chart shows all positively charged cations on the left. On the right you will find all the negatively charged anions. The top half of the chart contains all of the macronutrients and the bottom contains all of the micronutrients or trace elements. The macros, with the exception of calcium, are mobile within a plant. Nutrients in opposing quadrants have synergistic relationships, while nutrients in neighboring quadrants have antagonistic relationships.
**Navigating Nutritional Challenges **
Different systems offer different benefits and challenges. In any case prompt action and accurate diagnosis are essential for maintaining a healthy garden.
**Soluble Salts Damage**: Excessive accumulation of soluble salts, often stemming from over-fertilization or poor water quality, can lead to visible damage in hydroponic plants. Symptoms include wilting, dark green foliage, burned leaf margins, and root death. Regular monitoring of electrical conductivity (EC) and proper leaching practices can help mitigate soluble salts damage.
**Nitrogen Deficiency**: Inadequate nitrogen levels can result in stunted growth, light green foliage, wilting, and yellowing leaves. Monitoring and adjusting EC levels in nutrient solutions are vital preventive measures against nitrogen deficiency. For tomato plants the leaves will turn purplish in color from a nitrogen deficiency.
**Calcium Deficiency**: Calcium deficiency is characterized by brown leaf margins and fruit issues like blossom end rot. Proper pH control, moisture management, and ensuring adequate airflow can help prevent calcium deficiency.
**Iron and Magnesium Deficiency**: Yellowing between leaf veins is a telltale sign of iron and magnesium deficiencies. Monitoring media pH and nutrient balance is key to addressing these issues.
**Boron Toxicity**: Excessive boron can lead to leaf discoloration and reduced root growth. Accurate fertilizer calculations and water source analysis can help prevent boron toxicity.
**Conclusion: Nurturing Growth Through Precision Nutrition**
The success of any method or systems lies in the mastery of plant nutrition. Striking the right balance of essential nutrients, maintaining optimal pH levels, and understanding nutrient interactions are all pivotal for cultivating thriving gardens.
As we evolve the methods of growing plants, so too will our understanding of plant nutrition. Keep experimenting and taking notes of your plant production to unlock the full potential of plant cultivation. As with any endeavor, knowledge and vigilance will be the cornerstones of success.
You can find their article here: Penn State- Hydroponic Essential Nutrients