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Botanicare

Botanicare Cal-Mag Plus, A Calcium, Magnesium, And Iron Plant Supplement, Corrects Common Plant Deficiencies, Add To Water Or Use As A Spray, 2-0-0 NPK, Quart

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At a glance

Condition
New
Size
1 qt
Style
Cal-Mag Plus
Model
HGC732110
Weight
8 oz
Item Form
Liquid
Liquid Volume
946 ml
In the box
Gardening^Fertilizer and Soil^fertilizers
Warranty
1 year

Features 5

  • Highly fortified calcium, magnesium, and iron plant supplement formulated to correct common deficiencies
  • Supplement your existing nutrient program with Cal-Mag Plus
  • To Use: Mix well and use with every watering, as needed, for enhanced growth apply as a foliar spray
  • For use in containers, coco, hydrogardens, and when growing in soil

Description

Supplement your existing nutrient programs in reverse osmosis water, or when growing in soil or coco coir-based media, to compensate for a natural calcium draw with Botanicare Cal-Mag Plus. Formulated to correct common deficiencies, Botanicare Cal-Mag Plus is a highly fortified calcium, magnesium, and iron plant supplement. It contains a 2-0-0 NPK and can be mixed in with regular waterings or applied as a foliar spray to further enhance growth.

Specs 17

Brand Botanicare
Item Weight 8 ounces
Item Form Liquid
Liquid Volume 946 ml
Specific Uses For Product Plant Growth, Root Development, Soil Conditioning
Model Number HGC732110
Global Trade Identification Number 27
Manufacturer Hawthorne Hydroponics, LLC

Frequently asked questions

If you place your order now, the estimated arrival date for this product is: Nov 1 – Nov 2

Yes, absolutely! You may return this product for a full refund within 30 days of receiving it.

To initiate a return, please visit our Returns Center.

View our full returns policy here.

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Top Amazon Reviews

The "Insurance Policy" for Your Garden
Size: 1 quart Style: Cal-Mag Plus
Whether you are a hobbyist with a few houseplants or a professional managing a high-output indoor garden, if you are using Reverse Osmosis (RO) water, Coco Coir, or high-intensity LED lighting, this isn't just an "add-on"—it’s a necessity. Here is the professional breakdown of why this 2-0-0 formula is the gold standard. The Engineering: The "Plus" Makes the Difference Most calcium-magnesium supplements stop at the two namesake minerals. Botanicare’s "Plus" refers to the inclusion of Iron (Fe) and other trace minerals. The Iron Factor: In my 10 years of testing, I’ve found that yellowing leaves (interveinal chlorosis) are often misdiagnosed as just a magnesium deficiency when they are actually an iron lockout. The chelated iron in this formula acts as a catalyst for chlorophyll production, giving your plants that deep "forest green" luster that basic supplements can't match. Bio-Availability: This is a highly soluble, plant-available formula. It doesn't "fall out" of solution or clog emitters in hydroponic systems, which is a common failure in budget-brand minerals. The Versatility: Root Drench vs. Foliar Spray The CT-1's flexibility is its greatest asset. Root Feeding: It buffers the "cation exchange" in Coco Coir perfectly, preventing the medium from "stealing" calcium from your plants. Foliar Rescue: This is the "fast-track." If you see a deficiency starting, you can dilute this as a spray. Because it’s so clean, the leaves absorb it almost instantly, often reversing yellowing in as little as 48 hours. PROS Highly Concentrated: A little goes a long way. The standard dose is only 3–5ml per gallon, meaning this quart will treat hundreds of gallons of water. Corrects "LED Stress": Modern LEDs drive plant metabolism so hard that they often "burn" through calcium and magnesium faster than the base nutrients can provide. This bottle is the solution to that specific 2026 growing problem. Stabilized pH: Unlike some organic-heavy supplements, Cal-Mag Plus is relatively pH-neutral, so it won’t cause wild swings in your reservoir. Universal Compatibility: It works seamlessly with any base nutrient brand (FoxFarm, General Hydroponics, Advanced Nutrients, etc.). Clean Formula: It won't cause "salt crust" buildup on your fabric pots or in your irrigation lines. CONS The 2-0-0 NPK Warning: It contains a small amount of Nitrogen. If you are in the "late bloom" or "ripening" stage of a flowering plant and trying to zero out your nitrogen, you have to be careful not to over-apply this. Not for Low-Light Plants: If your plants are in low-light conditions, they likely don't need this level of supplementation. Over-applying can lead to "nutrient burn" in slow-growing species. Price: It is priced as a premium product, but given the concentration and the included iron, the value is actually superior to "cheap" alternatives. Overall Input Botanicare Cal-Mag Plus is the most reliable tool in my garden. It solves the #1 problem in modern gardening: mineral deficiencies caused by purified water and high-intensity lights. It is a rugged, scientifically sound, and battle-tested formula. If your leaves are turning yellow or your fruit is getting "blossom end rot," this is the cure. Reviewer Pro-Tip: If you are a Coco Coir grower, you should "pre-buffer" your medium with a half-strength solution of this before you ever plant. Also, if you’re using it as a foliar spray, apply it when the lights are about to go off or in the early evening. This prevents the "magnifying glass" effect of water droplets burning your leaves under intense light! Who is this for? Hydroponic growers, Coco Coir enthusiasts, LED indoor gardeners, and anyone struggling with yellowing leaves or stunted growth in their house or vegetable garden. ... show more
Reviewed in the United States on January 4, 2026 by Mr. Review
Great product as always
Size: 1 quart Style: Cal-Mag Plus
I recently added Botanicare Cal-Mag Plus to my plant care routine, and I’m really impressed with the results. The product arrived promptly and was excellently packaged, with no leaks or damage to the bottle, which is always a relief when ordering liquid supplements. From the first use, it was clear that this supplement was high quality. It’s easy to measure and mix with my regular nutrient solution. I started using it a few weeks ago, and my plants have shown significant improvement in their overall health and vigor. Cal-Mag Plus is fantastic for addressing common deficiencies in calcium and magnesium, which are crucial for plant growth. Since incorporating it into my routine, I’ve noticed my plants’ leaves are greener and more robust. There are no more signs of yellowing or other deficiency-related issues. This has been particularly beneficial for my tomatoes and peppers, which are heavy feeders and often prone to such deficiencies. Another great aspect of Cal-Mag Plus is its versatility. I use it for both my soil and hydroponic plants, and it integrates seamlessly with my existing nutrient regimen. It doesn’t cause any imbalances or issues, which makes it very convenient. I’ve also observed that my plants are more resilient to stress since I started using this supplement. They seem to handle fluctuations in temperature and light better, and their overall growth has been more vigorous. The added iron in the formula is a nice bonus, contributing to better chlorophyll production and healthier plants. Overall, I’m extremely satisfied with Botanicare Cal-Mag Plus. It’s a reliable, high-quality supplement that has made a noticeable difference in my plants’ health. If you’re dealing with calcium or magnesium deficiencies, or just want to ensure your plants have everything they need to thrive, I highly recommend giving this product a try. It’s become an essential part of my plant care routine, and I’m excited to see continued improvements as I keep using it. ... show more
Reviewed in the United States on June 21, 2024 by rick k
I've used this products for quiet a while and it's a must have.
Size: 1 quart Style: Cal-Mag Plus
Great all around plant nutrient that helps plants stay green and healthy . Of course one can deduce that if you are that far into botany and horticulture you have a grasp on the importance of this nutrient is . Very easy to use I use 5 mills or a teaspoon per gallon weekly . Helps the plants reach their full potential and avoid nutrient lockouts if used correctly. ... show more
Reviewed in the United States on March 9, 2026 by Mike L.
Cal mag
Size: 1 quart Style: Cal-Mag Plus
Worked great
Reviewed in the United States on October 7, 2026 by william robinson
Excellent for big leafy new foliage growth
Size: 1 quart Style: Cal-Mag Plus
Review Image by Derek
Review Image by Derek
Review Image by Derek
Review Image by Derek
I gave this to my 5 year old Meyer lemon tree and it made it produce the biggest leaves I’ve ever seen on it. This is all while overwintering it indoors in my shower. Notice the smaller leaves on it, those are the normal sized ones. Never seen it do this before! Looks much more healthy after 6 months indoors than previous winters, where it would often drop lots of leaves (they haven’t been dropping much). Admittedly I’ve used a little more than I was supposed to than the directions called for and just eyeballed it. I don’t use it every watering, maybe every 3 waterings or so and make it a little stronger than the directions ask. I also put it on my knockout roses and they went crazy with new foliage. One thing to note, this fertilizer seems to work excellent for new LEAF growth only, not for more flowers or bigger flowers. You have to use different fertilizer for that which I’m not sure I’m allowed to mention here. I’ve got a decent green thumb so I’ve been able to combine this fertilizer with other fertilizers for more roses on my knockouts without over Fertilizing. I never measure, I just eyeball it and they seem to love it. The key here is lots of water and well drained soils. One thing to note, with all of this new foliage you’ll get, you’ll be needing to water much more often and in larger amounts so be prepared to pump up your watering schedules and fluid volumes, especially if it’s really hot outside. In Summary, this is an excellent fertilizer if your plant is well drained but still getting yellow foliage. It will help produce new, abundant and possibly supersized leaves with the right amount of sun, water and drainage. ... show more
Reviewed in the United States on April 30, 2022 by Derek
Great for nutrient deficiencies and as an added feed supplement
Size: 1 quart Style: Cal-Mag Plus
Whether I use it as part of my feed schedule or to correct deficiencies it is hands down my favorite product to get the job done. I use with both hydroponic and soil based plants without any issues.
Reviewed in the United States on March 8, 2026 by winds1g1d
Need to do math with it lol
Size: 1 quart Style: Cal-Mag Plus
Has been super useful for my plants and lasts a long time a little goes a long ways make sure you measure it out and calculate what to use
Reviewed in the United States on July 22, 2026 by Kayla
Great Supplement for Plant Health
Size: 1 quart Style: Cal-Mag Plus
I’ve been using this supplement for my garden plants, and it has made a noticeable difference. The mix of calcium, magnesium, and iron is ideal for correcting deficiencies, especially for my tomatoes and leafy greens. I’ve seen improved growth and more vibrant leaves. It’s easy to mix with water, and I’ve had no issues with over-application or burn. My plants seem much healthier and more resilient after incorporating this into my routine. Overall, it's a solid addition to my plant care regimen. ... show more
Reviewed in the United States on November 11, 2024 by ALI EL-KHATIB
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