Hydroponic growing systems are becoming increasingly important in fruit, vegetable and ornamental production. In these systems, plants grow without soil, using substrate or water instead. This allows growers to control water and nutrient supply with high precision but also leaves little room for mistakes. Because root volume and buffering capacity are limited, the composition of the nutrient solution directly affects root-zone pH, nutrient uptake and crop performance.
This is where ammonium-free liquid calcium nitrate becomes relevant. It provides nitrogen in nitrate form and calcium in a liquid fertiliser that can be dosed accurately, without automatically adding ammonium to the nutrient solution. These benefits are also highlighted in an independent assessment by horticultural consultant Geerten van der Lugt, who identifies ammonium-free calcium nitrate as an important option across hydroponic cultivation systems.
Geerten van der Lugt’s two-page assessment can be downloaded below.
Plants can take up nitrogen as nitrate or ammonium, but ammonium has a stronger acidifying effect around the roots. In hydroponic systems, where buffering capacity is limited, too much ammonium can lower the pH in the root medium and make crop steering more difficult.
The advantage of ammonium-free calcium nitrate is that growers can apply nitrate and calcium without automatically adding ammonium. Ammonium can still be used when needed, for example to steer crop growth or correct pH, but it can be managed as a separate tool.
As greenhouse grower Kristian Solberg explained during an interview with Horti Daily: “Now we have more control over whether we want to add ammonium or not. Over the last two weeks I see the pH in the slabs (the hydroponic growing medium around the roots) going down and then I can reduce the ammonium individually, so it's a tool we've never had before.”
Calcium is one of the most important nutrients in high-value horticultural crops, but it is also one of the most difficult nutrients for the plant to take up and transport. High ammonium levels can reduce calcium uptake because ammonium competes with other positively charged nutrients, including calcium and magnesium.
This is particularly relevant in crops such as tomato and pepper, where limited calcium uptake can contribute to physiological disorders such as blossom end rot. By supplying calcium nitrate without ammonium, growers can apply calcium and nitrate without increasing the ammonium load in the root zone.
Liquid calcium nitrate also offers practical advantages. Water-soluble fertilisers are commonly supplied in 25 kg bags and must be manually opened, lifted and dissolved in fertiliser tanks. For a standard A+B tank preparation, this can involve several bags and repeated manual handling.
Liquid fertilisers reduce this labour requirement. They can be stored in tanks and dosed with pumps, improving accuracy and reducing the risk of mistakes when preparing nutrient recipes. This is especially relevant for larger greenhouses, where labour efficiency, dosing precision and operational reliability are increasingly important.
Today, the use of liquid fertilisers is often limited by logistics. Transporting liquid products over long distances is less efficient than transporting solids. This is one reason why liquid fertilisers are already well established in markets such as the Netherlands and Belgium, but less common in more distant regions.
Local plasma-based production can help overcome this barrier. By producing ammonium-free liquid calcium nitrate closer to where it is used, N2 Applied enables a more flexible model for hydroponic fertiliser supply.
For hydroponic growers, ammonium-free liquid calcium nitrate offers greater flexibility in nutrient management while simplifying fertiliser handling. Combined with local production, it also opens the possibility of shorter supply chains and improved security of supply.