| Management number | 250719864 | Release Date | 2026/09/17 | List Price | US$4.30 | Model Number | 250719864 | ||
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NPK Industries RAW Calcium/Mag 9-0-0 is a highly concentrated, fully water-soluble plant supplement containing 15% calcium and 3% magnesium. Formulated from calcium nitrate and magnesium sulfate, it helps prevent or correct two of the most common mineral deficiencies encountered in soil, coco coir and hydroponic cultivation.
The balanced formula supplies calcium for strong cell development and root growth, magnesium for chlorophyll production and photosynthesis, and a controlled amount of nitrate nitrogen to support nutrient uptake. Its concentrated powder dissolves rapidly and can be incorporated into nearly any compatible base fertilizer program.
The formula is derived from calcium nitrate and magnesium sulfate. RAW Calcium/Mag is a mineral supplement and does not replace a complete base fertilizer.
Calcium is an essential component of plant cell walls and newly developing tissue. It supports structural strength, healthy root growth and the development of growing tips, flowers and fruit.
Because calcium has limited mobility within plants, deficiency symptoms frequently appear in new growth first. Symptoms may include distorted young leaves, weak growing tips, reduced root development, blossom end rot in fruiting crops or tip burn in leafy vegetables.
RAW Calcium/Mag can help prevent these disorders when insufficient calcium is the underlying cause. Similar symptoms may also result from poor transpiration, high humidity, irregular watering, root damage or improper pH, so growing conditions should be evaluated before increasing the fertilizer rate.
Magnesium is the central element within the chlorophyll molecule, making it essential for photosynthesis and plant energy production. It also activates numerous enzymes involved in nutrient metabolism and cellular energy transfer.
Magnesium deficiency commonly appears as interveinal chlorosis on older leaves, where the tissue between the veins turns yellow while the veins remain green. Excess potassium, improper root-zone pH or mineral imbalance can also restrict magnesium uptake even when magnesium is present in the fertilizer solution.
Add RAW Calcium/Mag to water or a prepared nutrient solution at the following rate:
Begin with the lower rate when using reverse osmosis water, treating sensitive plants or adding RAW Calcium/Mag to an unfamiliar fertilizer program. Increase only when plant response and EC or PPM readings indicate additional supplementation is appropriate.
The NPK Industries RAW soil and coco schedule incorporates Calcium/Mag during vegetative growth and through much of flowering. The chart generally uses the higher 1/8-teaspoon rate during active growth and early-to-middle flowering, then reduces supplementation later in the flowering cycle.
Follow the current chart associated with the selected RAW base fertilizer. The ideal amount may change with source water, plant variety, growing medium and the calcium and magnesium already supplied by other fertilizers.
Never combine RAW Calcium/Mag directly with dry phosphate fertilizers or undiluted nutrient concentrates. Concentrated calcium can react with phosphorus or sulfur-containing fertilizers and form insoluble mineral deposits.
RAW Calcium/Mag may be used alongside RAW Grow or RAW Bloom when plants, source water or growing media require additional calcium and magnesium.
The official RAW all-in-one schedule includes Calcium/Mag at selected stages, even though the base formulas supply a broad range of essential nutrients. Use the appropriate chart rate and consider the mineral content of the source water before supplementing.
During flowering, RAW Calcium/Mag can provide additional calcium and magnesium without adding the heavy nitrogen concentration associated with a full vegetative fertilizer. The manufacturer states that its controlled nitrate content is suitable through bloom and is not intended to trigger unwanted plant stretch.
Coco coir can retain calcium and magnesium through cation exchange, reducing the amount immediately available to plants. Reverse osmosis and distilled water also contain little or none of the mineral content found in untreated water.
RAW Calcium/Mag may be especially useful in these applications. Start at a conservative rate, measure the completed nutrient solution and monitor runoff EC or PPM in coco to prevent mineral accumulation.
More Cal-Mag is not always better. Excess calcium can interfere with magnesium, potassium and other nutrients, while excessive magnesium can compete with calcium or potassium uptake.
Before increasing the rate, inspect:
Correcting the underlying growing condition is often more effective than repeatedly increasing fertilizer strength.
RAW Calcium/Mag is suitable for:
Ensure the powder has dissolved completely before operating fine emitters or irrigation equipment.
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