Hydroponic gardening require the management of nutrient concentrations in water, and the management of nutrient concentrations in water is measured in parts per million (PPM). Parts per million (PPM) are a measurement of how much nutrient food is dissolve in the water. If you provide too little nutrient food in the water, the plant will appear stunted and the plants will not grow proper.
If you provide too many nutrient food in the water, the salt concentration in the water become too high, and high salt concentrations causes nutrient burn. Nutrient burn occurs because high salt concentrations pull moisture out of the plant roots. Because you are growing plants in water instead of soil, you must manage the nutrient levels because soil act as a buffer that water does not provide.
How to Manage Nutrients and pH in Hydroponic Water
The nutrient requirements of a plant change as the plant grows, so you must change the nutrient levels as the plant grows. When a plant is in the vegetative stage, the plant need nutrients to build leaves and stems. When a plant transition to the flowering or fruiting stage, the plant needs different nutrients to produce energy and fruit.
Therefore, the recommended parts per million (PPM) levels must increase as the plant age. You must adjust the nutrient levels to match the metabolic demand of each stage of the plant life cycle. Different types of plant require different levels of nutrients.
For example, leafy greens like spinach require a light nutrient regimen, but heavy-feeding plants like peppers or cucumbers require a much richer nutrient solution. Because different plants has different requirements, you cannot use the same nutrient concentration for every plant. Additionally, even plants of the same species has different requirements if one plant is a microgreen and the other plant is a fruiting vine.
Nutrients consists of several different element that serve different function for the plant. Nitrogen is an element that promotes green growth, and phosphorus is an element that promotes root and flower development. Potassium is an element that manage the quality of the fruit, and secondary elements like magnesium and calcium are element that keep the internal processes of the plant running smooth.
If you do not provide the correct amount of one element, the plant will show symptom on the leaves. For example, a plant might show purple undersides or scorched edges if a plant is missing a specific nutrient. The pH level of the water is as important as the parts per million (PPM) level.
Even if the parts per million (PPM) level is correct, an incorrect pH level can cause nutrient lockout. Nutrient lockout is a condition where the nutrients are present in the water, but the plant roots is unable to absorb the nutrients because the pH level is incorrect. If you notice yellow leaves, you might think the plant need more nutrients, but an incorrect pH level might actualy cause the yellow leaves.
Adding more nutrients when the problem is an incorrect pH level will not fix the yellow leaves and may make the problem more worse. You must monitor the hydroponic system using tools such as digital meters to read conductivity and tools to adjust the pH level. You must also keep the nutrient solution clean and maintain the nutrient solution proper.
You should not let the reservoir sit for too long because stale salt can build up in the reservoir. Additionally, you must prevent light from hitting the nutrient solution because light cause algae to grow in the nutrient solution. Algae will consume the resources intend for the plants.
Finally, you must keep the water cool and well-oxygenated because the roots need oxygen to breathe and the roots needs nutrients to eat.