Magnesium Corrector – 1 Litre

This product is used to correct a magnesium shortage in the nutrient solution and contains 20% K2O.

Besides the basic elements N and P, K (potassium) is also crucial for every crop. Potassium makes cells robust (water balance) and induces flowering. Potassium also plays an important role in cell formation, osmosis regulation and carbohydrate metabolism. Potassium is also important for opening and closing the stomata, which allow excess heat to be released.

This product contains 10% MgO. One of the essential elements in the liquid mineral fertiliser line. Magnesium forms the reactive centres of chlorophyll, which converts light energy into chemical energy (ATP and ADP). Magnesium deficiency shows as chlorosis (slight discolouration) between the veins of older leaves and early leaf drop. An excess results in small leaves. This product has the same features as the other liquid mineral fertilisers offered by GroHo:

• MgO 10 works very quickly.
• MgO 10 is economical and contains no unnecessary ingredients.
• A 1:1000 dose raises total Mg by 2 mmol.

Dosage

In case of deficiency, add 2.5–10 ml per 10 litres of nutrient solution.

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.