Calcium is an often neglected plant food essential to plant growth. Calcium (15% N, 25% Ca0) combines quick acting Calcium and Nitrogen. Calcium deficiency shows as poor growth and specifically blossom end rot in tomatoes, heart rot in celery, tip burn in lettuce and bitter pit in apples. Used also in hydroponic formulations and as a bulking agent for potatoes and root crops. Rate of use 50g in 5 litres of water or 100g per sq.m for root crops.
Total Nitrogen (N) 15.5% Nitric Nitrogen 14.5% Ammoniacal Nitrogen 1% Calcium Oxide (Cao) 26.6% soluble in water.
A pure product containing 15% nitrogen and 19% calcium, is one of the most useful liquid feeds, the soluble calcium used to correct calcium imbalances, the nitrogen to keep growth moving steadily. The nitrogen is almost 100% in the nitrate form. Ammonical nitrogen should be avoided on seedlings. Calcium nitrate is recommended as a first feed on seedlings, the soluble calcium and nitrogen keep them safely growing. Rapidly expanding leaves need calcium to retain cell structure. Internal browning or tip burn in cabbage, lettuce and celery is attributed to shortages of soluble calcium. Other vegetable disorders, which can be corrected with calcium nitrate, are cavity spot in carrots and parsnips, and blackheart or heart rot in celery. Calcium nitrate is used in hydroponic systems not only to provide calcium but also because of its lack of ammonical nitrogen, which can be toxic in water culture. Two physiological disorders caused by lack of calcium are Blossom End Rot in tomatoes and Bitter Pit in apples. These can be corrected with soluble calcium supplied by calcium nitrate. Blossom End Rot (B.E.R.) shows as blackened fruit due to the plant not taking up calcium, particularly if insufficient water is given in hot weather. Remove all affected fruit and feed with 1oz. calcium nitrate to a gallon of water every week for four weeks. Bitter Pit in certain varieties of apples, particularly Bramley and Cox, shows a dark skin blemish which on storage goes brown. This also caused by lack of calcium. Commence spraying with 1 lb. of calcium nitrate to 10 gallons of water (plus peat and compost wetting agent) from mid June, and repeat at three week intervals. Avoid use in hot weather as this may result in leaf damage. Further sprays can be given later in the season to fully charge the fruit with calcium. Picked fruit can be soaked in the same strength solution for a few hours before storage as a final precaution