• Organic Amino Chelated Calcium — 30g kraft pouch with Dr Forest Cal-Mino Soluble Calcium Fertiliser label, 10% Calcium 8-0-0
  • Organic Amino Chelated Calcium — back of kraft pouch with OMRI Organic Approved, Application Rates, Guaranteed Analysis
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Dr Forest

Amino Chelated Calcium

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Cal-Mino — amino acid chelated calcium, 100% water-soluble

10% Chelated Calcium 8% Nitrogen Amino Acid Chelated 100% Water Soluble Plant-Based (Soy) OMRI Certified

Calcium is the nutrient most commonly responsible for blossom end rot in tomatoes, bitter pit in apples, tip burn in lettuce, and hollow heart in potatoes. The problem is rarely that calcium is absent from the soil — it is that calcium is phloem-immobile. Once deposited in a leaf or stem, it cannot redistribute to fast-growing fruit or new tissue. Conventional calcium supplements — lime, gypsum, calcium chloride — rely entirely on root uptake and xylem transport. If the plant is growing faster than the xylem can deliver, the fruit starves.

Cal-Mino addresses this with amino acid chelation. The calcium is bonded to amino acids from soy protein hydrolysate, creating small, organic molecules that the plant recognises as nitrogen-containing compounds. This allows foliar-applied calcium to enter the leaf more efficiently and — critically — to be transported through pathways that free calcium ions cannot access. Combined with 8% nitrogen from the amino acid base, it delivers two essential nutrients in one fully water-soluble powder.

10%Calcium (Ca)
8%Nitrogen (N)
100%Water Soluble
SoyPlant-Based Source

What Cal-Mino is used for in the garden

  • Preventing blossom end rot — the most common calcium-related disorder in tomatoes, peppers, courgettes, and aubergines; foliar calcium applied during fruit development reaches the tissue where it is needed most
  • Improving fruit firmness and shelf life — calcium strengthens cell walls and cross-links pectin in the middle lamella; well-supplied fruit is firmer, stores longer, and resists post-harvest decay
  • Correcting calcium deficiency quickly — foliar application bypasses slow soil-to-root-to-xylem delivery; amino acid chelation improves absorption through the leaf cuticle by 2–5x compared to inorganic calcium salts
  • Tip burn prevention in lettuce and brassicas — fast-growing leaf tips outpace xylem delivery; foliar calcium reaches the growing point directly
  • Strengthening cell walls across all crops — calcium is a structural component of every plant cell wall; adequate supply produces sturdier stems, thicker leaves, and better pest resistance
  • Stress recovery — transplant shock, cold damage, and waterlogging all impair calcium uptake; foliar feeding bypasses compromised root systems entirely
  • Soil biology support — the soy-derived amino acids and peptides are an excellent food source for beneficial soil microorganisms when applied as a root drench

Why amino acid chelated calcium instead of calcium chloride or lime?

Amino Acid Chelated Calcium — Cal-Mino

  • Calcium chelated with plant-derived amino acids — high foliar absorption
  • Small, uncharged organic molecules penetrate the leaf cuticle efficiently
  • Amino acids are metabolised as nitrogen — dual-nutrient delivery
  • Does not alter soil pH
  • 100% water-soluble with no residue — safe for sprayers and drip lines
  • Low salt index — no risk of leaf burn at recommended rates
  • Feeds soil biology when applied as a root drench

Calcium Chloride / Lime / Gypsum

  • Free calcium ions — poor foliar absorption through the waxy leaf cuticle
  • Chloride (CaCl₂) accumulates in tissue and can cause leaf burn at higher rates
  • Lime raises soil pH significantly — unsuitable for acid-loving plants
  • Gypsum is effective but slow-dissolving and not suitable for foliar use
  • All rely primarily on root uptake and xylem transport — the bottleneck that causes blossom end rot in the first place
Handcrafted in Stockport

Every Dr Forest product is made by hand in small batches at our workshop in Stockport, Greater Manchester. We source ingredients for quality, not cost.

The science of calcium delivery: why chelation changes everything

The calcium mobility problem

Calcium is unique among plant nutrients. Once deposited in a cell wall or vacuole, it is fixed in place. Unlike nitrogen, potassium, or magnesium — which can be remobilised from old tissue to new growth — calcium travels only upward through the xylem, pulled by transpiration. It cannot enter the phloem. It cannot move from leaves to fruit. It cannot redistribute to where demand is greatest.

This is why blossom end rot occurs even in calcium-rich soil. The fruit is growing faster than the xylem stream can supply it. Irregular watering, high temperatures, and rapid growth all worsen the imbalance. Adding more calcium to the soil does not solve the problem if the transport system is the bottleneck.

01

Amino Acid Chelation & Foliar Uptake

The leaf cuticle is a waxy barrier evolved to prevent water loss. Charged mineral ions like Ca²⁺ struggle to cross it. When calcium is chelated with amino acids, the resulting molecule is small, uncharged, and organic — properties that dramatically improve cuticular penetration. Research consistently demonstrates 2–5 times greater foliar absorption rates for amino acid chelated minerals compared to inorganic salts. This makes foliar spraying a genuinely effective calcium delivery method rather than a token gesture.

02

Beyond the Xylem — Amino Acid Transport

Free Ca²⁺ ions are restricted to xylem transport. Amino acid chelated calcium may access additional transport pathways because the plant recognises the chelate as a nitrogen-containing organic molecule. Amino acid and peptide transporters exist in both xylem and phloem tissues. While calcium remains inherently difficult to redistribute once deposited, delivering it as an amino acid chelate to the leaf surface nearest the developing fruit gives it the shortest possible distance to travel — bypassing the root-to-fruit xylem bottleneck entirely.

03

Calcium in Cell Wall Structure

Calcium cross-links pectin chains in the middle lamella — the cement between plant cells. This structural role is why calcium-deficient tissue is soft, easily bruised, and prone to collapse. In fruit, adequate calcium supply during development produces firmer flesh, thicker skin, better storage life, and greater resistance to post-harvest pathogens. Research on apples (bitter pit), tomatoes (blossom end rot), and lettuce (tip burn) consistently shows that calcium applied directly to the developing tissue outperforms soil-applied calcium for preventing these disorders.

04

Dual Nutrition — Calcium + Amino Acid Nitrogen

Cal-Mino delivers 8% nitrogen alongside 10% calcium. The nitrogen is entirely organic — present as amino acids and short peptides derived from enzymatic hydrolysis of non-GMO soybeans. This is not urea or ammonium nitrogen. It is metabolised directly by the plant as organic N, supporting protein synthesis, chlorophyll production, and enzyme activation without the osmotic shock of inorganic nitrogen salts.

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Soy Protein Hydrolysate — The Carrier

The amino acid base is produced by enzymatic hydrolysis of non-GMO soybeans. Enzymatic hydrolysis (as opposed to acid hydrolysis) preserves the biologically active L-form amino acids that plants recognise and metabolise. The hydrolysate contains a broad spectrum of amino acids including glutamic acid, aspartic acid, glycine, and proline — each with specific roles in nitrogen assimilation, mineral chelation, stress tolerance, and osmotic adjustment.

06

Soil Biology Benefits

When applied as a root drench, the amino acids and peptides in Cal-Mino serve as a high-quality food source for rhizosphere microorganisms. Published research shows protein hydrolysate applications increase microbial biomass, improve nitrogen cycling efficiency, and enhance the plant's natural nutrient acquisition pathways. The biological benefit compounds over successive applications, building long-term soil health alongside immediate calcium delivery.

Scientific References

  1. White, P.J. & Broadley, M.R. (2003). Calcium in plants. Annals of Botany, 92(4), 487–511.
  2. Halpern, M. et al. (2015). The use of biostimulants for enhancing nutrient uptake. Advances in Agronomy, 130, 141–174.
  3. Colla, G. et al. (2015). Protein hydrolysates as biostimulants in horticulture. Scientia Horticulturae, 196, 28–38.
  4. Saure, M.C. (2005). Calcium translocation to fleshy fruit: its mechanism and endogenous control. Scientia Horticulturae, 105(1), 65–89.
  5. De Freitas, S.T. & Mitcham, E.J. (2012). Factors involved in fruit calcium deficiency disorders. Horticultural Reviews, 40, 107–146.

How to use Cal-Mino: application rates & guide

100% water-soluble — dissolves completely

Cal-Mino is a fine, spray-dried powder that dissolves fully in water with no sediment or residue. Apply as a foliar spray, root drench, through fertigation or drip systems, or added to compost teas. No straining required. Use fresh solution within 24 hours.

Application rates

Foliar spray — blossom end rot prevention

Rate: 2.5–3.5g per litre of water  |  Frequency: Weekly from first fruit set until harvest

Dissolve in water and spray developing fruit and surrounding foliage in early morning or late evening. Target the fruit trusses directly — calcium needs to reach the fruit tissue, not just the upper leaves. Begin at first flower and continue throughout the fruiting period. This is the primary application for preventing blossom end rot in tomatoes, peppers, courgettes, and aubergines.

Foliar spray — general calcium supplementation

Rate: 2.5–3.5g per litre of water  |  Frequency: Every 7–14 days during the growing season

Spray both leaf surfaces. Particularly effective for lettuce (tip burn prevention), brassicas, apples, and soft fruit. The amino acid chelation ensures rapid absorption through the leaf cuticle.

Root drench — soil and container application

Rate: 2.5–3.5g per litre of water  |  Frequency: Every 2–4 weeks during the growing season

Dissolve and apply to the root zone. Suitable for all container and bed-grown crops. The amino acid chelation protects calcium from soil lock-up and the peptide base feeds beneficial soil biology.

Hydroponics and fertigation

Rate: 2.5–3.5g per litre of water  |  Frequency: As part of the regular feed cycle

Fully soluble with no residue — safe for drip lines, NFT, and recirculating systems. Add to the reservoir after mixing main nutrients. Perform a jar test before first use to confirm compatibility with your existing nutrient solution.

Compost tea additive

Rate: 2.5g per litre of tea  |  Frequency: Add during the brew cycle

The amino acids and peptides boost microbial activity in the tea while the chelated calcium becomes part of the biologically active solution.

Step-by-step preparation

  1. Measure the powder. Half a level teaspoon is approximately 2.5g. For a standard 10-litre watering can, measure 25–35g (5–7 level teaspoons).
  2. Dissolve in water and stir. Sprinkle powder onto the water surface and stir until fully dissolved. Dissolves quickly with no sediment.
  3. Apply immediately or within 24 hours. For foliar sprays, use a fine mist sprayer targeting fruit, growing tips, and both leaf surfaces. For root drenches, apply evenly around the root zone.
  4. Time foliar sprays correctly. Spray in early morning or late evening — not in full sun. Cool, still conditions maximise absorption time before the solution dries.
  5. Store dry powder sealed. Keep in a cool, dry place. The powder is hygroscopic and will absorb moisture if left open.
Key timing for blossom end rot prevention

Blossom end rot is set during early fruit development — once the black patch appears, that fruit cannot be saved. Prevention is everything. Begin foliar calcium sprays when the first flowers open and continue weekly throughout fruiting. Consistent watering is equally important — calcium transport depends on steady transpiration. Irregular watering is the single biggest trigger for blossom end rot, even in calcium-rich soil.

Works well combined with…

Use alongside Micro-Amino for a complete micronutrient + calcium programme. Combine with Seaweed Powder for biostimulant activity — the alginic acid improves foliar wetting and mineral uptake. For soil-applied calcium alongside potassium and magnesium, use Yorkshire Polyhalite as the slow-release base and Cal-Mino as the fast-acting foliar top-up.

Frequently asked questions about Cal-Mino

Cal-Mino is a preventive measure, not a cure. Once the black patch appears on a fruit, that fruit cannot be saved — the cells have already collapsed. The purpose of Cal-Mino is to deliver calcium to developing fruit before deficiency occurs. Begin weekly foliar sprays at first flower set and maintain consistent watering. Used this way, it significantly reduces the incidence of blossom end rot in tomatoes, peppers, courgettes, and aubergines.
Most garden soils already contain adequate calcium. Blossom end rot is rarely caused by absent soil calcium — it is caused by the plant's inability to transport calcium fast enough to rapidly developing fruit. Calcium moves only upward through the xylem with water. If watering is irregular, or the plant is growing very fast, the fruit starves even when the soil is calcium-rich. Foliar-applied amino acid chelated calcium reaches the fruit tissue directly, bypassing the soil-to-root-to-xylem bottleneck.
Calcium chloride (CaCl₂) is a common foliar calcium source, but the free Ca²⁺ ion struggles to penetrate the waxy leaf cuticle. Amino acid chelation wraps the calcium in a small, uncharged organic molecule that passes through the cuticle far more efficiently — research consistently shows 2–5x better absorption. Additionally, calcium chloride delivers chloride ions that can accumulate and cause leaf burn at higher rates. Cal-Mino delivers nitrogen instead of chloride — an additional nutrient rather than a toxicity risk.
Yes. Cal-Mino is derived from enzymatic hydrolysis of non-GMO soybeans and calcium carbonate — both natural ingredients. It is OMRI certified for organic agriculture. No synthetic chelating agents, no chemical processing.
Yes. Calcium is required by all plants for cell wall structure, cell division, and membrane stability. Cal-Mino is safe for vegetables, fruit, flowers, shrubs, trees, lawns, and hydroponic crops. It is particularly valuable for tomatoes, peppers, lettuce, brassicas, apples, and soft fruit — all crops with high calcium demand or known susceptibility to calcium-related disorders.
No. The calcium in Cal-Mino is derived from calcium carbonate but is chelated with amino acids — the solution pH is 4–6, slightly acidic. It does not raise soil pH the way lime does. Safe for acid-loving plants like blueberries, azaleas, and rhododendrons.
For blossom end rot prevention, spray weekly from first flower set through to the end of harvesting. Target the fruit trusses and surrounding foliage directly — calcium needs to reach the developing fruit, not just the upper canopy. Spray in early morning or late evening when conditions are cool and still.
Cal-Mino is compatible with most water-soluble fertilisers, seaweed extracts, and fulvic acid. It pairs particularly well with Micro-Amino for a combined calcium + micronutrient foliar programme. Avoid mixing with concentrated phosphate solutions — calcium and phosphate can form insoluble precipitates. Perform a jar test before tank-mixing with any new product.
Yes. 100% water-soluble with no sediment. Safe for drip lines, NFT, and recirculating systems. The slightly acidic solution pH (4–6) is compatible with most hydroponic nutrient regimes. Add to the reservoir after mixing main nutrients and check EC accordingly.
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