Optimal Calcium Delivery from Engage

Do you often wonder which is the best calcium to use at root level or as a foliar nutrient?
Do you sometimes feel that foliar calcium fertilisers don’t work or don’t give the results you expected?

If so, then please read on.

When it comes to root calcium for both tree and soft fruit, calcium nitrate is almost always the best option as it delivers a primary nutrient source with the calcium you need.

In tree fruit, if calcium is required from your soil analysis and pH is low, calcium can be best applied from granulated lime, however this is strongly bonded to its anion of carbonate. This is also true if applying gypsum, as again the calcium is strongly bonded to sulphate. This reduces the availability of the calcium as it is left to the roots or soil microorganisms to aid its release.

In soft fruit production calcium nitrate has to be the primary source due to lack of other options. Calcium chloride is not acceptable for soft fruit production as the adverse anion of chloride has negative effects in the rootzone especially to chloride sensitive species such as strawberries. Other products can help; indeed our calcium chelate Bio-Chel has a strong following in the UK to replace up to 20% calcium to aid nitrogen balancing.

Traditional calcium nitrate comes ammonia which is not ideal for optimal berry production. That is why at Engage Agro we strive to support optimal calcium delivery at root level with Calci-Pure calcium nitrate.

Calci-pure comes in a fine chip form with zero anti-caking agent and only 0.3% ammonia compared to standard calcium nitrate at 1.1% ammonia. Also it is 27.5% Calcium making it the
strongest calcium nitrate available with the highest level of solubility.

New for 2020, we release Calci-Pure liquid, our most advanced liquid calcium nitrate. It has a massive 20% calcium (CaO w/w), 11% N and most importantly 0% ammonia.

For foliar calcium, a plethora of products are available and all purporting to be the best. Most are based around calcium nitrate or calcium chloride or have technologies attached to aid assimilation or penetration. Other versions are available but sell at lower volumes due to price.

Key points to know when choosing a foliar calcium for fruit crops:

  1. Calcium use in fruit development is only from early bud through to end of cell division. Once fruit starts to swell, calcium delivery to fruit slows and eventually stops and then calcium only serves the growth of the plant.
  2. Calcium is xylem mobile only, so don’t spray it on leaves thinking the plant is going to move it around the vascular system to the fruits – this doesn’t happen.
  3. Calcium is a huge molecule and is extremely difficult to get into leaves; it needs support to open the pores on leaves to allow absorption. Ideally organic materials are the best option.
  4. Cations such as calcium will enter leaves at 1000 times the volumes of anions such as nitrates and chlorides. So if your calcium is strongly bonded in these salts the calcium is massively slowed down from entering the plant.
  5. Calcium is a highly reactive so cannot be mixed with many plant protection products or nutrients containing sulphates or phosphates/phosphites due to insoluble precipitates being formed in the spray tank or on leaf.
  6. Calcium nitrate sprays drive apical growth which stimulates transport of calcium to the growing tips, away from fruits. During early development is it best to avoid foliar sprays containing with calcium nitrate.

For all of the above reasons Engage Crop Solutions developed the Bio-Chel Calcium chelate. It is pure calcium so it ensures optimal delivery via roots and most importantly, leaves, flowers and fruits.

Bio-Chel Ca is only calcium and has no anions to slow its progress into the leaves, flowers and fruits.
It is organically chelated and contains natural spreaders and other organic materials to stimulate higher calcium acceptance.

It is totally safe on crops and can be used at any point during the growing season even on open flower. As Bio-Chel is chelated it is non-reactive so sits perfectly in spray tanks with plant protection products and all nutrients.

The Bio-Chel range encompassed three products:

Bio-Chel Ca Powder

At 22% CaO, the powder is designed to be used as a supplement to irrigation systems to aid nitrogen balance and to provide a fully bioavailable source of calcium which will optimise fruit and crop support.

See Product

Bio-Chel Ca Liquid

At 10% CaO, it is the worlds’ most concentrated calcium chelate liquid designed for use as a full season foliar calcium which can be used through to optimise fruit quality and shelf/storage life. It is pure calcium and is fully tank mixable.

See Product


Opti-Cal is Bio-Chel Ca plus Engage’s PAP technology. Designed for later season use, Opti-Cal contains a concentrated package of calcium signalling proteins which we call PAP technology. When applied Opti-Cal delivers calcium into the leaf and signals the cells to accept it into calcium depleted areas. Opti-Cal is proven to have the ability to elevate the outer calcium levels of fruit tissues which is so important as harvest approaches.

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