Introduction to hydroponics

What is hydroponics?

Hydroponics is a method of growing plants without soil, instead using a water-based nutrient solution to deliver essential minerals directly to plant roots. In a hydroponic system, plants are often supported by an inert medium—such as rockwool, clay pebbles, or coco coir—that holds them in place while the nutrient-rich water circulates around their roots. By bypassing traditional soil, hydroponics allows for precise control over nutrient concentrations, pH levels, and water delivery, often resulting in faster growth rates and higher yields. Because the plants receive everything they need through the solution, growers can avoid many soil-borne pests and diseases, use water more efficiently, and cultivate crops in diverse environments, from indoor setups to commercial greenhouses.

Your first hydroponic system

One of the simplest ways to start your first hydroponic system is to take a clean glass bottle—such as a recycled juice or soda bottle—fill it about two‐thirds full with fresh water, and then place a healthy cutting of a herb like rosemary, basil, or mint into the bottle so that its lower stems and nodes are submerged. Position the bottle in a bright spot with indirect sunlight (a windowsill works well), and change the water every few days to keep it fresh and oxygenated. Within one to two weeks, you should begin to see fine white roots developing from the cut end of the herb, signaling that your plant is successfully adapting to a water‐only environment. And that's it - you’re witnessing how easy and effective hydroponics can be (the technique used here is also called "water culture", or "deep water culture (DWC) in large commercial setups").

Next steps

Although the cutting may continue to produce roots and survive for a short time in plain water, without added nutrients it won’t be able to sustain long‐term growth or thrive. Initially, the herb relies on stored food reserves in its stem and leaves, but as those reserves are depleted, you’ll begin to see slow or stunted growth, pale or yellowing leaves, and weaker stems. Over a few weeks, essential elements like nitrogen, phosphorus, and potassium—which are not present in sufficient quantities in plain water—become limiting, so the plant won’t develop new healthy foliage or sturdy roots. In other words, the herb may stay alive for a while, but without a balanced nutrient solution, it will gradually weaken and fail to flourish as a mature, productive plant.

To ensure your herb cutting thrives beyond those initial rooting stages, you’ll need to source a basic hydroponic nutrient mix—remember, a little goes a long way. First, measure the exact volume of water in your bottle (for example, 500 mL or 1 liter) so you can calculate the correct nutrient dosage. Most beginner nutrient bottles include a recommended ratio, such as 2 mL of concentrate per liter of water; simply multiply that ratio by your measured volume. After adding the nutrients, gently swirl the water to dissolve the solution fully, and then top up to your original water mark if needed. To maintain optimal conditions, replace the nutrient solution every one to two weeks: drain the bottle, rinse it lightly to remove any sediment, and then refill with fresh water and the calculated amount of nutrients. By staying consistent with measurement and replacement, you’ll provide the precise balance of nitrogen, phosphorus, potassium, and trace elements your herb needs to grow vigorously.