Flood table pack with 10 pots: system, grow medium and nutrients

The ten pots included are 4-litre fabric pots, and the material allows air to pass through the sides. Your root balls breathe across their entire surface rather than receiving air only from the top, which reduces root circling against the edges. The trade-off is that they also dry out through the sides: on a breezy terrace in midsummer, keep an eye on the grow medium rather than following a watering frequency you've read elsewhere. They can be machine-washed on a cold cycle between crops, without fabric softener, and fold flat for winter storage. Across the 86 x 86 cm of usable surface on the tray, the ten pots leave room between plants; you can fit up to 22 if you're growing lettuce or herbs, provided you keep them all at the same stage, as they all share the same reservoir and therefore the same solution.

The TriPart range, available in mains and solar versions, splits nutrition into three parts. Micro, at NPK 5-0-1, supplies calcium, iron and trace elements and is used from seedling to harvest. Grow, at 3-1-6, delivers the nitrogen and potassium needed during the growth phase. Bloom, at 0-5-4, delivers the phosphorus and potassium needed during flowering. During active growth, allow 1.8 ml of Grow, 1.2 ml of Micro and 0.6 ml of Bloom per litre in your tank; during flowering, Bloom increases to 2.4 ml. Pour each bottle separately into the water in your tank, never add one concentrate directly to another. These doses are based on soft water; with water that already contains significant levels of calcium and magnesium, reduce Micro slightly, otherwise the starting conductivity will be too high before the plants have had a chance to take up anything.

Offered as the third version, Pro Organic comes in two bottles rather than three and replaces mineral salts with ingredients of plant and animal origin. The maximum dosage is 2 ml per litre: Grow ranges from 0.25 ml at start-up to 2 ml during vegetative growth, and Bloom holds at 2 ml during flowering. The fundamental difference lies in the process: these materials must be mineralised by micro-organisms before they become available to plants, which makes nutrition slower and more buffered beneath your crops. This also means more regular maintenance of the reservoir and pump is required. The range complies with European organic farming regulations. In practice, this mineralisation requires a solution that does not drop below 18 °C; if it does, the micro-organisms slow down and nutrition lags behind the plants' needs.

100 litres circulate in a closed loop for two to three weeks. Plants take up ions unevenly, evaporation concentrates what remains, and pH shifts without warning. Outside the useful range, elements that are present in your reservoir become unavailable, and you see your plants stall despite a correctly dosed solution. Aim for 5.5 to 6.5 up to pre-flowering, then 6.4 to 6.8, and always adjust last, once the nutrients have been added. The powdered pH corrector is dosed at around 1 g per 5 to 6 litres, dissolved before being poured in. Our article on pH regulation covers measurement and correction in detail. With a volume like this, a correction takes around an hour to distribute evenly, so take your control reading after that delay rather than immediately after dosing.

The number of flood cycles is something you settle through observation, not by following a ready-made table. With the coco fibre supplied, start with three cycles during the day, then watch: a grow medium that never dries out at the surface needs one cycle removed; a pot that dries out by late afternoon needs one added. The season shifts this setting, a plant in full summer heat drinks noticeably more than in March, and a table placed outdoors also responds to the wind. At night, the cycles stop: transpiration is almost nil, and a grow medium that stays permanently saturated will eventually suffocate the roots. One last pointer is worth more than a timer: lift a pot at the end of the day, and its weight tells you in an instant whether the grow medium has dried out as much as it should, that one action replaces any frequency table.

A residue of solution remains in the tray between cycles, and it is this that must be kept in the shade, algae can establish themselves within a few days on any lit surface. Cover the exposed surface with empty pots or a board. At the end of a growing cycle, drain the reservoir, rinse it with clean water, and rinse the pump strainer under the tap; a clogged filter slows filling time without giving any indication that it is doing so. Check that the tray is level before restarting, as a tray on a slope will leave one side dry at every flood cycle. Once a season, if your water is hard, circulate diluted white vinegar, then rinse twice before making up a fresh nutrient solution, limescale reduces pump flow well before it becomes visible on the walls.