Hydroponics at home: the basics
Grow herbs and greens with their roots in water, not soil
How it works
In hydroponics, soil is replaced by water with nutrients dissolved in it. Coconut coir, perlite, vermiculite, rockwool or expanded clay pellets hold the plants up.
It can use up to 90% less water than growing in soil, there's no weeding, and leafy crops grow quickly.
Simple systems
Home setups range from a jar to a pumped system.
- No-pump jar or tub, often called the Kratky method: as plants drink, an air gap opens where the upper roots take in oxygen.
- Wick system: a wick draws solution up to the plants, with no electricity needed.
- Deep water culture: plants float over the solution, with an air pump and air stone keeping roots supplied with oxygen.
- Ebb-and-flow and nutrient film systems use a pump, and often a timer.
Start with greens
Lettuce, kale, spinach and other leafy greens, plus herbs, are the best plants to start with. Fruiting crops like tomatoes and cucumbers take much longer and need more space, and they don't suit simple no-pump kits. In a simple kit, lettuce can be ready to pick in 5 to 6 weeks.
Feed and check
Without soil, the water supplies everything.
- Use a complete hydroponic nutrient, with the secondary and micronutrients plants need, at the rate on the label.
- Keep the pH around 5.5–6.5, the range most plants prefer; lettuce copes up to about 7.0. A simple test kit tells you.
- Replace the solution every 2 to 3 weeks, and clean the system before replanting.
- Keep light out of the reservoir, or green algae will grow and slow the crop.
Light, air and power
Indoors, most food crops need grow lights; herbs usually get 14 to 16 hours a day. Roots need oxygen too, so aerate the solution and keep it between 65 and 80°F (18–27°C). Waterlogged roots starve for air and can rot.
Systems with pumps stop working in a power cut, so check them after outages. Keep cords and connections away from water.
Related plant problems
Sources
- University of Illinois Extension: Growing without soil: Getting started with hydroponics at home
- University of Hawaii CTAHR: A Simple Hydroponic Growing Kit for Short-Term Vegetables
- UF/IFAS Extension: Growing Lettuce in Small Hydroponic Systems
- University of Illinois Extension: Home Hydroponics
General guidance, not a diagnosis. Written by PlantWiz in our own words from the sources above.