Calboost ( Micronized Calcium Carbonate)

CalBoost (micronised calcium carbonate)

CalBoost is ultra fine micronised calcium carbonate, a powdered lime ground so small it can be suspended in water for a soil drench or foliar spray. It supplies calcium to living soil and media between dressings of lime.

At a glance

• Type: amendment (calcium carbonate, water suspendable)
• Analysis: calcium carbonate; pure calcium carbonate is 40% calcium (no batch sheet published yet)
• Use for: calcium by drench, foliar spray or in the feed line
• Rate: 15 g (one tablespoon) per 4 L of water as a soil drench, every 2 to 4 weeks
• Form: micronised powder

What it is

CalBoost is pure calcium carbonate milled to a very fine particle size. Fine particles have far more surface than ordinary lime, so they dissolve sooner in soil and can be held in suspension long enough to pour or spray. Pure calcium carbonate is 40% calcium by weight.

What it does

• Calcium builds cell walls and root tips. It is immobile in the plant, so a shortage shows first as twisted or burnt new growth and as blossom end rot in fruit.
• The carbonate part reacts with acid, so CalBoost also nudges soil or media pH upward. Used by drench it is a gentle way to hold pH in a mix that is drifting acid.
• Finer is faster: the same mineral at a smaller particle size acts sooner and runs out sooner.

How to use

• Foliar spray: mix 5 g (one teaspoon) of CalBoost per 4 L of water. Apply as a fine mist to the foliage for thorough coverage. Use every 1 to 2 weeks during the growing season, or as needed.
• Soil drench: mix 15 g (one tablespoon) per 4 L of water. Apply to the soil around the base of the plants. Use every 2 to 4 weeks for continuous calcium availability.
• Hydroponic and feed systems: add 5 g (one teaspoon) per 4 L of nutrient solution as part of the regular feeding schedule.
• Shake well before use and keep the mix agitated. Apply in the early morning or late afternoon when temperatures are cooler, and avoid peak sunlight to prevent leaf burn.
• Compatible with most fertilisers and pesticides, but always run a jar test before mixing with other products.
• Calcium carbonate does not dissolve in water. It stays as a suspension, settles fast and can block fine nozzles and drippers. Keep it agitated and flush lines after use.
• Carbonate raises pH. Watch the pH of your feed and media, and do not use it where pH is already at the top of the range.
• Foliar calcium stays on the leaf it lands on. It is a fast fix for a visible shortage; the soil is where to correct it.

Learn more in fifteen seconds

• Calcium: what it does
• Foliars: fast fixes, then the soil
• Particle size sets the clock

Handling and storage

• Wear a mask to avoid inhaling particles and open the container in a well ventilated area.
• Wear gloves and eye protection, and wash hands after use.
• Once opened, keep sealed, dry and out of direct sunlight.
• Not for human consumption.