DWC (deep water culture): the common entry point
A net pot holding the plant sits in the lid of a reservoir, with the roots hanging directly in oxygenated nutrient solution below. An air pump and air stone keep the water saturated with dissolved oxygen, which is what keeps roots from drowning. A 5-gallon bucket kit is the standard single-plant starter setup, usually $30 to $60 for bucket, net pot, and air pump.
Growth is fast because roots have direct, constant access to nutrients and oxygen with none of the resistance a solid medium adds. The tradeoff is temperature sensitivity: reservoir water above about 70°F starts losing dissolved oxygen and becomes a much friendlier environment for Pythium (root rot). Keeping reservoirs at 65 to 68°F, with an aquarium chiller if your grow space runs warm, is the single biggest factor in DWC success.
Heads upA DWC air pump failure is a same-day emergency, not a next-week one. Roots in still, unoxygenated water start suffering within hours. Keep a spare pump or battery-backed air pump on hand if you're running DWC unattended.
Ebb and flow (flood and drain): the forgiving middle ground
Plants sit in an inert medium, usually clay pebbles (hydroton), inside a tray. A pump on a timer floods the tray with nutrient solution from a reservoir below, then drains it back after a set period, several times a day. The medium holds some moisture between floods, which buffers short pump or timer problems that would be fatal in straight DWC.
This is the more forgiving hydro method for someone coming from soil or coco, since the clay pebbles act like a small safety margin instead of roots sitting directly in water with zero buffer. Build cost for a small home setup runs $80 to $200 depending on tray size and pump quality.
NFT (nutrient film technique): built for smaller, faster plants
A thin, continuously flowing film of nutrient solution runs through a sloped channel, with roots partially exposed to air above the film and partially in the flow. It's efficient with water and nutrients and is common in commercial lettuce and herb operations, less common for full-size cannabis plants because a mature root mass tends to outgrow and clog a standard NFT channel.
Where NFT does work well for cannabis is smaller, faster-cycling plants: clones being rooted, or compact autoflower strains grown at higher density. For a full-size photoperiod plant taken to harvest, ebb and flow or DWC scale better.
Aeroponics: highest ceiling, least room for error
Roots hang in an enclosed chamber and are misted with nutrient solution on a timer, often seconds on and several minutes off. Maximum oxygen exposure to the roots produces the fastest growth rates of any of these four methods when it's running correctly.
It's also the least forgiving. A clogged mister nozzle or a pump failure can dry out and damage exposed roots in well under an hour, since there's no standing water or moist medium to buffer the gap. This is generally an advanced or commercial-grower method, not a first hydro system.
Which one to actually start with
If you've never run hydro before: start with ebb and flow or a single DWC bucket, not NFT or aeroponics. Both give you real hands-on experience with pH and PPM management and reservoir temperature control, and both have enough of a buffer that a missed check-in for a day doesn't kill the plant.
Move to NFT or aeroponics only after a full successful cycle or two on DWC or ebb and flow, once daily pH/PPM checks and reservoir temperature control are already a habit rather than a chore.
What all four have in common
Every hydro method needs daily pH checks (target 5.5 to 6.5) and EC/PPM monitoring, since there's no soil buffer to absorb a mistake. Budget for a decent pH pen and TDS meter, $30 to $70 combined, before building any of these systems. Nutrient solution should be fully changed every 7 to 14 days even if levels look fine, since nutrient uptake is uneven across the ion balance and stale solution drifts out of range in ways a simple PPM reading won't catch.