What it is
Hydroponics is growing without soil: the roots live in water with dissolved nutrients and lots of air. The plant sits in a net pot (a mesh pot) filled with expanded clay pebbles, which don't feed it: they just hold it up.
What an rdwc is
The game's system is an rdwc ("recirculating deep water culture"). Each plant has its own bucket of water. The buckets are connected by pipes to a tank, and a pump keeps the water circulating all the time. An air pump with air stones fills the water with bubbles.
The bubbles are key: the root breathes. In soil the air stays between the grains; in water you have to put it in.
Why it yields more
The root always has water, food and air, without searching for them. The plant spends less on building roots and more on growing: it usually goes faster and yields more than in soil, with the same care.
What you have to control
pH: it's measured every day and kept between 5,5 and 6,5 (most commonly 5,8 to 6,2). In water the pH moves fast, and out of range the root can't take up some nutrients.
Ec: it measures how much fertilizer is in the water. Little is used for seedlings (0,6 to 1 MS/CM), more in veg (1,2 to 1,6) and more in flowering (1,6 to 2,2). Hydro fertilizer comes in two parts, a and b, because mixed in the bottle they spoil.
Water change: every 7 to 14 days the tank is emptied and refilled with new water and nutrients: over time it gets unbalanced and builds up residue.
The water temperature
The ideal water is between 18 and 22 °C. The warmer it is, the less oxygen it can hold, and above 24 °C fungi like pythium thrive: root rot. A healthy root is white and firm; a rotten one turns brown, slimy and smelly, and the plant droops even though it has water.
To cool it, people use water chillers or, in a pinch, frozen bottles inside the tank. It also helps if the tank gets no light or heat.
The weak spot
Everything depends on electricity. If the power goes out, the pump and the air stop, and in a few hours the root runs out of oxygen. That's why many growers have a backup battery for the air pump. In soil, a power cut doesn't kill anyone.
▲ Pros
- +15 % grams and +10 % speed
- No watering: the water is always there
▼ Cons
- Very expensive, and the pumps use power all day
- Needs a pH meter and an EC meter
🎮 Practice it in UnderGrow
It's an optional add-on (shop › add-ons) for the corner, the tent, the grow room or the breeding room, and it needs the pH meter and the EC meter. It gives +15 % grams and +10 % speed. Instead of watering, you change the water every 12 game days (12 real h) with the dose for the stage (it uses a+b nutrients), you fix the pH every 36 game h, 1.5 real h (it uses pH down, or you add the pH doser) and you keep the water from going above 24 °C. All the numbers are in rules › add-ons.
▶ Play free