Choosing a system is the first step in a successful hydroponic gardening experience. Consider your available space, lighting, budget, and time constraints before purchasing any equipment or settling on a unit to build yourself. Also think about what you want to grow, whether you may want to expand, and recurring costs.
The simplest way to start is with a passive system. These use a wicking material to draw nutrients up to the roots, or the root tips are suspended in a stationary solution with the main portion of the rootball hanging in the air. Passive systems are affordable and easy to build yourself. They are best suited for smaller plants. Active systems are best for larger plants and gardens. An active system uses a pump and timer to flow nutrients around the plant’s roots and to provide aeration. It costs more, but is more efficient and requires less attention, since the pump and timer handle everything automatically. Once you’ve looked at passive vs. active systems, you’ll need to choose between media-based and water culture systems.
Media-based systems such as ebb-and flow (flood-and-drain), top-feed (drip), or bottom-feed systems rely on a growing medium to support the plants and hold nutrient solution around their roots. Most operate on timers, alternately wetting the medium to wash out salts and replenish nutrients and then draining so the plants can draw in atmospheric oxygen. Setup is more complex, costs are higher, and media needs to be replaced occasionally. These systems need to be protected from power outages, which can leave vulnerable roots high and dry if the pump stops functioning. On the other hand, these systems are super efficient, since nutrients are recycled back into the reservoir, and use of timers means they need less attention from you.
Water culture systems usually operate without media. Plants are anchored in a plank that floats on the reservoir, suspending the roots in the nutrient solution. This kind of system is simple and inexpensive to set up and is great for water-loving plants, though special care must be taken if you want to use it with large plants. You can use rockwool cubes or small amounts of gravel to anchor plants like tomatoes and cucumbers that get top heavy when they start to bear fruit. You can also use plastic flaps, foam rings, fiber cups, or plastic collars for plant support, or tie plants to a trellis.