Hydroponics for beginners: DWC, NFT, wick and ebb-and-flow systems explained

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Hydroponics means growing plants without soil, with the roots taking water and nutrients from a solution instead. It is used on large commercial farms, but the same ideas work in a kitchen. Herbs and salad leaves grown this way can be harvested all year, with no compost and little mess. This guide explains the main systems, what each needs and what to grow first.

What every system has in common

Water with dissolved nutrients: plants still need nitrogen, potassium, calcium and the rest. Without soil, all of it has to come from a hydroponic nutrient made for the purpose.
Oxygen at the roots: roots need air as well as water. Each system's design is mostly about how it gets oxygen to them.
Support: plants sit in net pots filled with an inert medium such as clay pebbles, rockwool or coco coir, which holds the plant up but feeds it nothing.
Light: a bright window or a grow light.

Deep water culture (DWC)

Plants sit in net pots in a lid above a container of nutrient solution, with their roots hanging into it. An aquarium air pump and an air stone bubble air through the water so the roots do not suffocate.

Good for: lettuce, salad leaves, basil and other herbs.
Pros: cheap, simple, fast growth.
Cons: if the pump stops, the roots can suffer quickly. Warm water holds less oxygen, so a container in a hot room is a risk.

Nutrient film technique (NFT)

Plants sit in holes along a slightly sloping channel. A pump runs a thin film of solution along the bottom of the channel, past the roots, and back to a reservoir. Roots get water from the film and air from the space above.

Good for: lettuce, herbs, strawberries.
Pros: uses little water, widely used commercially.
Cons: depends on the pump. If it stops, the thin film dries out fast. Roots can block the channel if plants grow large.

Wick system

Fabric or rope wicks draw solution up from a reservoir into the growing medium. No pumps and no electricity.

Good for: small herbs and leafy plants with modest thirst.
Pros: very simple, silent, cheap.
Cons: wicks cannot move water quickly, so large or fruiting plants go short. Nutrient salts can build up in the medium.

Ebb and flow (flood and drain)

A tray of plants in a medium is flooded with solution from a reservoir by a pump on a timer, then allowed to drain back. As the water drains, it pulls fresh air into the medium.

Good for: a wide range, including larger plants.
Pros: versatile, good oxygen at the roots.
Cons: more parts: pump, timer, overflow. A failed timer can leave roots dry or waterlogged.

Also worth knowing

Kratky: a passive version of DWC with no pump, described in its own guide in this room. Excellent for a first try.
Drip systems: a pump drips solution onto each plant's medium, common with larger crops.
Aeroponics: roots hang in the air and are misted. Efficient but less forgiving.

Easy first crops

Lettuce and other salad leaves: the classic first crop. Quick, compact and forgiving.
Basil, mint, parsley, chives, coriander: grow well, though coriander can bolt in warmth.
Pak choi, rocket, spinach and other leafy greens.
Strawberries and cherry tomatoes: possible, but they need more light, more nutrients and more support. Try them once you have grown a few rounds of leaves.

Starting out

Choose one small system, such as a DWC tub or a Kratky jar.
Start seeds in rockwool cubes or plugs and move them across once roots show through.
Mix a hydroponic nutrient at the strength on the label and check the pH.
Give plenty of light.
Keep notes: dates, how much nutrient you mixed and what you saw.

Share which system you started with, or ask about one you are considering, in the comments.