Hydroponics fertiliser and pH control pack, 3 x 1 L

The pH- in the pack is powdered urea phosphate, inert when dry and strongly acidic once dissolved. You never pour it as it is into the reservoir: first you dissolve 1 g of powder in 5 to 6 litres of water, then you use this solution to correct the pH of your plants' water. The 250 g in the pack therefore make 1,250 to 1,500 litres of acid solution, of which each correction uses only a part, a larger one the harder your tap water is. Kitchen scales accurate to the gram are enough for weighing, and the container should be closed again straight afterwards, because the powder absorbs moisture from the air and forms lumps that are difficult to weigh.

Take three pepper plants in a 50-litre hydroponic tank, where you renew the solution every week. During 5 weeks of growth at 1.5 ml per litre, you pour in 75 ml of NovaMax Grow per week, i.e. 375 ml. Pre-flowering lasts 2 weeks at 1 ml of each NovaMax per litre, which amounts to 100 ml of each fertiliser. Next come 6 weeks of flowering at 2.5 ml of Bloom per litre, i.e. 750 ml, then 2 weeks of ripening at 5 ml of FinalPart per litre, i.e. 500 ml. Bloom is therefore the bottle used most, with 850 ml consumed out of 1 litre, while you have about 525 ml of Grow and half of the FinalPart left to start the next crop.

These mineral fertilisers must not be poured into the water of a pond stocked with fish. The powdered pH- contains urea, which turns into toxic ammonia in a coupled system, and the phosphorus it adds feeds algae. The pack does, however, have its place on a decoupled loop, where the plants receive their own nutrient solution, separate from the fish water. The pH test is useful in both circuits, with a higher target in aquaponics, 6.8 to 7.0, which looks after the plants, the fish and the nitrifying bacteria alike. To feed a system with fish directly, you should choose the Aquaponic Mix instead, formulated for that purpose.

The parcel contains the three 1 litre bottles, the powdered pH-down and the 30 ml bottle of reagent with its colour chart, for a weight of about 4.7 kg. Liquid fertilisers keep for 5 years after opening, stored upright with the cap screwed tight, between 5 and 35 °C and out of direct sunlight, and you shake them before each measurement, as a deposit may form at the bottom. The pH-down is kept dry, tightly closed and out of reach of children, while the test reagent is stored away from light with its chart. When one bottle runs out before the others, you can buy it again on its own in 1 litre or in a 5 litre container, such as the NovaMax Bloom, which is the first to go on a crop of fruiting vegetables.