Fertilizer Science: Nutritional Basics of Hydroponic Gardening

One of the fundamental tenets of hydroponics is the exclusion of soil from the growing equation. While this factor allows for a 90% reduction in water usage compared to traditional agriculture, it also requires that 100% of plant nutrients be supplied by you, the grower.

Hydroponic fertilizers are available in dry and liquid form. Water-soluble powders are easy to use -- just measure, pour, stir, repeat. Meanwhile, some fluid nutrient solutions are pre-mixed and others are concentrated, and must be diluted.

As in indoor gardener, you can fine-tune the nutrient recipe for your operation based on the specific plants you choose to cultivate. Some of the most popular are edible fruits and vegetables such as strawberries, lettuce, bell peppers and spinach as well as herbs including rosemary, parsley, sage, thyme, mint, chives, chicory and basil among others.

Plant nutrition involves 16 elements, three of which -- oxygen ,hydrogen and carbon -- are readily available in the air and water inherent in any hydroponic habitat. The other 13 are categorized as primary macronutrients, secondary plant nutrients and micronutrients.

Primary Macronutrients

These include nitrogen which is essential for protein creation and photosynthesis; phosphorus which is key to healthy cell membranes; and potassium -- a crucial signaling element for all stages of plant development. All can be found in the main nutrient mix of most hydroponic fertilizers.

Secondary Plant Nutrients

These include calcium, magnesium and sulfur. Calcium must be mixed into your water separately due to how it reacts with other nutrients and is essential for stabilizing plant cellular structure. Magnesium helps with photosynthesis and sulfur plays an important role in the forming of peptide bonds. Both can be found in the main nutrient mix of most fertilizer products.


These are boron, chlorine, copper, iron, manganese, molybdenum and zinc. While they play an overall lesser role in plant nutrition, these seven elements are crucial to the long-term health of a plant that would otherwise atrophy and die after the first or second generation.

Complete the Connection

Introducing nutrients into your hydroponic mix is the first half of the delivery equation. The second half is ensuring your plants can absorb these nutrients by maintaining proper pH (power of Hydrogen) levels. Hydroponic pH levels are a measurement of hydrogen ion concentration -- the acidity or alkalinity of the water flowing through your system. All mineral nutrients are salts, essentially, and when they dissolve into water they become ions. Optimal pH levels depend on your specific crop, but on the pH scale of 0 - 14, most occur in or near the 5 to 6 range.

Determine Your Ratios

Nutritional ratios in hydroponic fertilizers are measurements of the primary macronutrients (nitrogen, phosphorus and potassium). These are three numerical values separated by a dash such as the recommended ratios for bell peppers which is 10-5-10 -- meaning 10% nitrogen, 5% phosphate and 10% potassium. Most plants have specific optimal ratios which should be determined before choosing the fertilizer product that is ideal for your grow.

X Hydro Supply is the premier online hydroponic equipment supplier specializing in plant nutritional products. Take a look at our massive selection of fertilizers for every size and type of hydroponic operation.











By Luke Schmaltz

Fertilizer scienceHydroponic fertilizersHydroponic gardeningHydroponic micronutrientsHydroponic ph levelsHydroponic plant nutrientsIndoor gardening plant nutrients