What nutrients do plants need? The 17 essential elements
Hydroponics means growing plants without soil. Hydroponic nutrients give plants everything they need to grow. This guide covers what nutrients plants need, how much, how to measure them and what else matters when you start a hydroponic garden.
What nutrients do plants need?
Without a mix of essential nutrients plants cannot grow, just like people need food. In total there are 17 essential elements: 14 minerals (3 macronutrients and 11 micronutrients) plus three non-mineral elements. Some sources group calcium, magnesium and sulfur as secondary macronutrients, but the total of 17 is the same.
Macronutrients
Macronutrients are needed in large quantities. They are nitrogen (N), phosphorus (P) and potassium (K), commonly called NPK on soil fertilisers. Nitrogen and phosphorus are integral to plant growth: they are used to build and copy DNA and to produce sugars and energy. Without them the plant cannot make new cells, which means no new growth or fruit. Potassium works in the parts of the plant that control the rate of photosynthesis by regulating water and carbon dioxide intake. It also helps the plant make starches and sugars, which makes it hardy and less susceptible to changes in the weather.
Micronutrients
Micronutrients are needed in tiny quantities but are just as important as macronutrients. There are 11: calcium, magnesium, sulfur, boron, chlorine, iron, manganese, zinc, copper, molybdenum and nickel. They are included in hydroponic nutrients so plants can use them in a range of processes, and they are essential if you want productive plants.
Non-mineral elements
The three non-mineral elements are oxygen and hydrogen, which the plant mostly gets through water, and carbon, which it gets from the air.
How much nutrient do my plants need?
The amount of nutrients in a liquid solution is measured with an electrical conductivity (EC) meter. The meter has two metal probes and runs a small electric current between them. The more dissolved salt in the water, the higher the EC reading. Hydroponic nutrients are essentially dissolved minerals, so an EC meter is a good way to measure them.
Each plant has different nutrient needs. Our plant nutrient chart shows the ideal EC, PPM and pH for each plant.
Other factors in hydroponics
pH
The pH of a nutrient solution matters because different minerals dissolve at different pH levels. A plant that needs a lot of one mineral may prefer a higher or lower pH. You can measure pH with a pH meter and adjust it with pH adjusters to get the most out of your nutrients.
Do not stress, though. For the average home grower, most plants grow well without worrying too much about pH.
Temperature
Plants grown hydroponically need similar conditions to plants grown in soil. Most prefer temperatures between 20 and 30 degrees Celsius, with humidity of 40 to 60%.
Oxygen
High oxygen levels promote growth and reduce the chance of root rot. In most hydroponic systems, oxygen reaches the roots through an aeration pump, a circulation pump or a flood and drain system that exposes roots to air.
Shop nutrients
Browse our hydroponic nutrients, or keep learning:
Sources
What we would use
Our herbs and leafy greens nutrients and indoor plant nutrients cover the full profile, and a pH meter helps you check your solution.
Written by the gathera team. Last reviewed October 2026.