Phosphorus Corrector – 1 Litre

Solution for correcting phosphorus in the nutrient solution; contains 20% P2O5.

Phosphorus is known for activating root activity and plant flowering. Phosphorus also plays a role in forming cellulose membranes and is a molecular building block of DNA and the energy carriers ATP and ADP. Phosphorus also supports good sugar metabolism and enzyme formation.

Phosphorus deficiency shows as slow growth, purple discolouration of the veins on the leaf underside and purple stems caused by anthocyanin build-up. Excess phosphorus results in a plant growing with induced zinc deficiency.

• P 20 is absorbed quickly and has no side effects.
• P 20 is free from chlorides and other excess ingredients.
• A 1:1000 dose raises total P by 3.5 mmol.

Dosage

To stimulate root development and/or flowering, add 1–5 ml per 10 litres of nutrient solution. Caution: too high a dose can affect the uptake of other nutrients.

1 unit = 1 litre

How do you control these parameters?

Nutrient solution

The plant consumes the solution, and every day the volume in the tank drops. This volume should be topped up every day with water, not with nutrient solution. Plants absorb much more water than nutrients, and since the nutrient solution is saline, topping up with solution every day salinises it until the dissolved salts exceed what the roots can tolerate. If this happens, plants stop growing – not from a lack of nutrients, but because of an excessively high osmotic potential at the roots.

Control the pH of the nutrient solution

As they take up nutrients, plant roots change the pH of the nutrient solution. The pH indicates how acidic or alkaline the nutrient solution is. Plants develop best between pH 5.5 and 6.5, and as they grow they change the pH of the solution. That is why the pH should be measured every day after topping up the solution with water. If it is outside the 5.5–6.5 range, adjust it with acid if above 6.5, or with base if below 5.5.

Control the electrical conductivity of the nutrient solution

As plants grow, the nutrients in the solution are used up and the solution becomes depleted. Eventually the solution can no longer supply the nutrients the plants need. At that point the solution should be replaced. One of the biggest problems is knowing when to change it.

A solution containing salts (nutrients) can conduct electric current. The higher the concentration of dissolved salts, the greater this conductivity. So a drop in electrical conductivity tells you when the nutrient solution needs changing. The easiest way to know the nutrient concentration is to use a conductivity meter.

One of the main reasons growers choose water-culture systems is that growth and maturity are usually 15–25% faster. Growers can still reach the desired plant size with a short vegetative period. So to get optimal early production from these systems, using the right nutrient mix and having the right conditions matter far more.