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Cal-Mag® 2-0-0

Cal-Mag® Plus is a specialized calcium, magnesium & iron, plant supplement designed to compensate for deficiencies in some commercial and hydroponic nutrient programs. Cal-Mag Plus also compensates for the natural calcium draw of coco coir fiber.

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Cal-Mag® Plus provides a precise balance and optimal ratios of the calcium, magnesium, and iron that are critical throughout all stages of growth, especially in heavily fruiting plants and fast blooming annuals. Cal-Mag Plus is fortified with a proprietary blend of select trace minerals to help maximize yields in fruiting and flowering plant varieties, prevent blossom end rot in tomatoes and peppers, and reduce tip burn in lettuce. When used in combination with nutrient solutions Cal-Mag Plus functions as a catalyst to increase the uptake of essential minerals.

Cal-Mag Plus contains: calcium, magnesium, iron, boron, zinc, manganese, molybdenum, copper, cobalt, iodine, beneficial vitamins, twenty essential amino acids and select botanical plant extracts.

To view a video about the benefits of using Cal-Mag Plus click on the usage application tab below.

  • Inhibits blossom end rot by providing additonal calcium and increasing nutrient uptake.
  • Strengthens plant cells and tissues for increased resistance to stress.
  • Prevents interveinal chlorosis, stunted growth rates, and upward leaf curl.
  • Increases cell division and plant tissue development.
  • Increases flower and fruit sets.
  • Increases water, nutrient, and carbon dioxide uptake.
  • Increases growth rates and crop maturity.
  • For hydroponics, soil and container gardens
  • Tomatoes, Peppers, Lettuce, fruit and flower bearing plants
  • Use with Botanicare® Nutrients or preferred nutrient program
  • Always use to supplement reverse osmosis water
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Q: Will the iron in Cal-Mag Plus be affected by my magnetic pump?
A: The chelated form of iron present in Cal-Mag (iron EDTA) is non-magnetic, and will not be removed from the nutrient solution by the pump. You won’t need to purchase a grounding probe, and if you follow the recommended application rates, you should not notice any iron deficiencies in the plants.

Q: Why is it recommended to use Cal-Mag Plus with R.O. Water?
A: Reverse Osmosis (R.O.) water filtration forces water through a series of fine mesh screens removing all contaminants that are too large to pass through the screens. Large Calcium and Magnesium molecules commonly found in tap water are included in this filtration and are also removed from the filtered water. Cal-Mag Plus is therefore recommended for any grower who utilizes R.O. water to return these essential elements back into the water.

Q: Why is it recommended to use Cal-Mag Plus when growing in Coco Coir based media?
A: Coco’s high cation exchange draws calcium away from plants. Therefore using Cal-Mag Plus with these mediums will offset this effect which prevents deficiencies from occurring.

Q: Can I foliar spray with Cal-Mag Plus?
A: Yes you can foliar spray with Cal-Mag Plus and it is a great way to quickly correct deficiencies during the vegetative and transition phases. We do not recommend applying any product via foliar spray late into the flower cycle when growing tight flowers, as excess moisture can lead to mold and mildew. Apply at the rate of 5 ml (1 tsp) per gallon a maximum of twice a week.

Q: Will the iron EDTA in Cal-Mag Plus harm beneficial microbes?
A: There are no components in Cal-Mag Plus that are inherently toxic to any beneficial microbes or fungi. EDTA is technically toxic to fungi, but has only been shown to act as a fungicide at extremely high concentrations exceeding 10,000 parts-per-million. Using enough Cal-Mag Plus to provide this level of EDTA would easily kill the plants before the fungi or beneficial would be effected. At the listed application rates, Cal-Mag Plus provides a level of iron EDTA far below the level of toxicity, and is perfectly safe to use with beneficial microbes and fungi.

Q: What does the ‘Plus’ in Cal-Mag Plus mean?
A: The ‘Plus’ refers to the iron, organic acids, vitamins, and over 72 trace minerals also contained in the formula. These elements not only help overall growth but also help to enhance uptake of macro nutrients such as calcium and magnesium.

Q: What application rate should I use during flowering? More or less than the vegetative phase?
A: You should use 5 ml/gallon of Cal-Mag Plus during the vegetative and early bloom stages. During the halfway point of the flowering stage, you might want to reduce the application to 3 ml/gallon, to avoid adding excess nitrogen to the nutrient solution based upon your plant specific needs.

Q: What is the ideal grow room temperature?
A: Most plants do well between 65˚F - 80˚F (18˚C - 26˚C) for light and dark cycles. Having a lower temperature during the plant’s dark cycle is common. When temperatures are higher than the recommended range, you may experience more pest problems, reduced dissolved oxygen in the nutrient solution, and increased plant transpiration which can increase humidity and irrigation demand. Cooler than recommended temperatures may slow growth.


Q: What is the ideal nutrient water temperature? Should it be cooler than the grow room?
A: The ideal water temperature in hydroponics is from 68°F - 75°F (20°C - 24°C). There is less dissolved oxygen available in water at higher temperatures.


Q: How often should I change my reservoir water? 
A: We recommend changing your reservoir water completely every 10 - 14 days. Even though you can top off your reservoir with water to make up for water lost by evaporation and plant transpiration, you can’t accurately measure the nutrients left in the water after plants have taken up some of the nutrients. (For instance, plants may need / deplete more nitrogen during some growing stages.) The only way to ensure optimal growing success is to know the exact ration of NPKs you’re feeding by starting fresh with a new batch of nutrient solution.


Q: Are your products organic?
A: We have many certified/listed organic products and use many organically derived ingredients in our formulations. Organic certified compounds are naturally occurring compounds like bat guano or alfalfa meal, rather than mineral compounds that are mined or synthesized. While not all of our products are CDFA, OMRI, NOP certified organic we strive to use natural and organic inputs whenever possible.


Q: Which nutrients or supplements should I use to increase flower size?
A: Our bloom booster, Hydroplex, contains high levels of phosphorus and potassium which are beneficial for flower initiation and structure. Phosphorus will increase the number of flowers and potassium will increase the weight of flowers.


Q: I’m having a problem with scum in my reservoir, what do I do?
A: We recommend covering your nutrient solution reservoir to decrease light and therefore decrease the likelihood of unwanted algae, bacteria or fungal growth. These organisms need nutrients, light, and water to multiply and thrive. Keeping your room and water cool will slow the potential growth of these organisms. Clean your reservoirs between crops and plant stages of growth. You can use bleach or hydrogen peroxide to clean them, but rinse well to remove all cleaning product residue before refilling with nutrient solution.


Q: Which Botanicare nutrient system would be best for me to use?
A: We’ve created 4 different base nutrients for different uses and purposes. CNS17 is the simplest mineral base with all of the necessary macro and micro nutrients included in one bottle. Pure Blend Pro is our natural and organic one-part nutrient that contains natural and organic based ingredients. KIND is a three-part mineral based nutrient which requires no Calcium/Magnesium supplementation and allows the grower the most flexibility in application. Growilla is a dry organic nutrient formulation (OMRI listed/CDFA) which delivers excellent results outdoors in soil and in large containers.


Q: Should I use all the supplements you manufacture?
A: The short answer is, no. We make a wide variety of supplements that can be used for different purposes. Some products like Pure Blend Tea and Liquid Karma are fairly similar, but they were developed for different reasons. We recommend Pure Blend Tea be used with KIND to add flavors and aromas, and Liquid Karma be used with Pure Blend Pro base nutrients to add additional bio-stimulants. Check our website or product pages and information sheets for clarification--our website has some excellent Pre-Developed Recipes to guide you.


Q: Which grow medium do you recommend?
A: We were one of the first companies to recommend coco coir for growers, and we do think it delivers excellent results. We have 3 premium coir based formulas to choose from - Cocogro, Readygro Aeration and Readygro Moisture. Cocogro can be blended with your favorite amendments or you can chose our Readygro Aeration or Moisture depending on your irrigation needs.

Q: Are your plastics food-safe?
A: Our trays and reservoirs are made of BPA-free plastic, but they are not rated for food storage. Plastic pots are used to grow all kinds of food and are rarely food grade because the plant roots are not eaten. Food grade plastics are used to store, prepare, or serve food. Our trays are made from extra thick, high-impact, BPA-free ABS plastic and have a smooth finish for easy cleaning.

Q: How and when do I check my pH and PPM levels?
A: You should check the pH and PPMs of your nutrient solution after mixing the nutrient solution and periodically throughout the usage of the solution (if using a recirculating system). You should use a pH meter, colorimetric pH solution, or indicator strips to test the nutrient solution or the runoff from the plants. You can use a PPM or EC meter to test the concentration of the nutrient solution.

Q: When should I adjust my pH levels and what should pH level be?
A: Check and adjust pH after you have mixed your nutrient solution and periodically during the usage of the nutrient solution if using a recirculating system and the pH becomes out of range. We recommend a pH level between 5.5 - 6.5 for maximum nutrient availability.


Q: Do you have a nutrient or supplement that is pH stable so that when I adjust my pH, it won’t change?
A: The pH of the nutrient solution will vary depending on the source water, the nutrient concentration, and the uptake of nutrients by the plant if using a recirculating system. You should always check your pH and adjust it to ensure best availability of nutrients to the plant.


Q: What is the difference between PPM, EC and TDS?
A: TDS stands for total dissolved solids, PPM stands for parts per million, and EC stands for electrical conductivity; which are acronyms used to quantify the concentration of nutrients as positive or negatively charged salts in the solution or growing substrate. Meters measure the electrical conductivity (EC) of the salts and can convert to PPMs or TDS.

Q: What conversion factor does Botanicare use for nutrient calculations to convert EC to PPMs?
A: Botanicare uses the 700 ppm to 1.0 EC factor. This is standard for most EC or ppm meters as well, but check the specifications of your meter to be sure.

Q: What should my PPMs or ECs be at each stage of growth?
A: The concentration of nutrients that plants require depends on their stage of growth, i.e. smaller plants need less food. See our nutrient calculator, or more information in our Hydro 101 section.


Q: When should I add nutrients?
A: You should add nutrients as soon as the first true leaves emerge if growing from seed or when the plant has developed roots if growing from cuttings. You can find detailed information on our website using the nutrient calculator, feed sheets, or on the back of the bottle of our base nutrient formulations.


Q: Should I top off with straight water or water with nutrients added? 
A: If you are growing in a system that re-uses nutrient solution, like with the ebb and flow method, you should top off with straight water if the reservoir level is lowered by evaporation or plant uptake. Remember that you will have no way of knowing how much of each nutrient (like nitrogen) has actually been used by the plants (and is therefore depleted in the reservoir water.) We recommend completely changing out and replacing all the nutrient solution every 10 - 14 days so you know the exact ratios you are feeding the plants.


Q: Do I need to use humic or fulvic acid with Liquid Karma or Pure Blend Pro?
A: No, both of these products contain these naturally occurring organic acids.   


Q: Can I use hydrogen peroxide with your nutrients and supplements?
A: We do not recommend using hydrogen peroxide in application to plants as this may kill off beneficial microorganisms that live in the substrate surrounding root zone of the plant. Hydrogen peroxide is an environmentally friendly product for cleaning and sterilization, but is not recommended in nutrient solution mixtures.


Q: What is the difference between Pure Blend Tea and Pure Blend Pro?
A: Pure Blend Tea is an organically derived compost tea supplement which can be used with many base nutrient systems to increase flavors, aromas and terpene production. Pure Blend Pro is a premium, complete, one-part base nutrient system that contains the same natural and organic compounds which add flavors and aromas found in Pure Blend Tea. It is not necessary to use Pure Blend Tea if using the Pure Blend Pro nutrient line.


  • Soil Container Gardens: Use 1 tsp (5 ml) per gallon (4 l) of water.
  • Accelerated formula: Use 2 tsp (10 ml) per gallon (4 l) of water.
  • Hydrogardens (Aeroponics, NFT, Soilless Mix):
Use with preferred hydroponic formula. Desired range of nutrients are:
  • Nitrogen (N): 160-250 ppm
  • Calcium (Ca): 160-280 ppm
  • Magnesium (Mg): 45-75 ppm
  • Iron (Fe): 2-7 ppm
For best results:

Use with every watering with standard fertilizer program. This recommended application rate is normally sufficient to make up for any deficiencies in most soil or hydroponic formulas.

***Note - In hydroponics, iron falls out of the solution relatively fast due to use of magnetic driven pumps without grounding probes and high levels of dissolved oxygen from air stones and pumps.

Guaranteed Analysis:

  • Total Nitrogen (N): 2.0%, 2.0% Nitrate Nitrogen
  • Calcium (Ca): 3.2%
  • SMagnesium (Mg): 1.2%, 1.2% Water Soluble Magnesium (Mg)
  • Iron (Fe): 0.1%, 0.1% Chelated Iron (Fe)

Derived from: Calcium Nitrate, Magnesium Nitrate, Iron EDTA