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Botanicare
Botanicare Cal-Mag Plus

Botanicare Cal-Mag Plus

Best price now

$18.99at AmazonObserved at 9:57 PM

45% under what the other stores charge

Compared across 3 stores. Prices are checked against each store and labelled with when.

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Our take on the Botanicare Cal-Mag Plus

Botanicare Cal-Mag Plus is a liquid calcium, magnesium and iron supplement for plants, with a 2-0-0 NPK analysis. It is used in hydroponics, coco coir and container gardens to head off calcium and magnesium deficiencies, especially when plants are fed with soft or filtered water. The 1-quart bottle is the common size; the best new price is $18.99 at Amazon as of November 6, 2026, with three stores listing it.

Best forCoco coir and hydroponic growersGrowers using soft, filtered or RO waterContainer and indoor gardenersCorrecting calcium or magnesium deficiency
Pros
  • Supplies calcium, magnesium and iron in one liquid
  • 2-0-0 adds no meaningful nitrogen load
  • Mixes easily into reservoir or watering can
  • Works in coco, soil and hydroponic systems
  • Widely used, so dosing advice is easy to find
Cons
  • Not OMRI listed, so not for certified organic grows
  • Iron can stain surfaces and reservoirs
  • Overdosing can lock out other nutrients
  • 1-quart bottle is small for large reservoirs

Botanicare Cal-Mag Plus prices at every store

  • Cheap and Easy Hydro StoreNew

    In stock

    $34.50+ $12.90 shippingObserved at 9:57 PM
    Visit Cheap and Easy Hydro Store
  • HTG SupplyNew

    In stock

    $35.98+ $22.20 shippingObserved at 9:57 PM
    Visit HTG Supply
  • AmazonNew

    Availability unknown

    As an Amazon Associate, Deal.ai earns from qualifying purchases.

    $18.99Observed at 9:57 PM
    Visit Amazon

Also available at

  • Garden Dominion SupplyCheck price at Garden Dominion Supply

Botanicare Cal-Mag Plus price history

Lowest price we've seen: $18.99 on Nov 7 at Amazon. Tracked across 4 stores since Nov 7.

What reviewers say

Growers rate Cal-Mag Plus as a reliable fix for calcium and magnesium problems in coco and soft-water setups. Most complaints are about dosing and about it not being organic-certified.

What people mention
  • Deficiency fixPraisedGrowers say it corrects calcium and magnesium deficiency symptoms within a week or two.
  • MixingPraisedUsers report it dissolves cleanly into water with little sediment.
  • DosingMixedSome find the label rate too strong and cut it, while others follow it as written.
  • Organic useCriticisedOrganic growers note it is not OMRI listed and cannot be used in certified organic programs.
  • ResidueCriticisedA few owners report staining or buildup in reservoirs and on equipment.

Specifications

Type
Plant Supplement
Primary Use
Fertilizer
Use
Hydroponics, Container gardens
Soil Type
Soil, Coco, Coco coir
Form
Liquid
NPK Ratio
2-0-0
Micronutrients
Iron
Quantity

Questions and answers

What is Cal-Mag Plus used for?
It adds calcium, magnesium and iron to plants grown in coco, hydroponics or soft water, where those nutrients run short. It has a 2-0-0 NPK ratio, so it adds almost no nitrogen.
Can I use it in soil?
Yes. It is labeled for soil, coco coir and hydroponic systems, though it is most often reached for in coco and RO-water grows.
Is it organic?
No. Botanicare lists it as inorganic based and it is not OMRI certified, so it does not fit certified organic programs.
How much do I add per gallon?
Follow the bottle label for your system and water type. Many growers start at a low rate and raise it only if deficiency symptoms persist.
Is $18.99 a good price for the quart?
That is the best new price among three stores as of November 6, 2026. Cal-Mag Plus is a commodity supplement, so compare per-quart cost if you buy larger sizes.
Can I mix it with other nutrients?
Yes, but add it to water separately and stir before adding other nutrients to avoid precipitation. Do not mix concentrated calcium and phosphate products directly.
Where is the Botanicare Cal-Mag Plus cheapest?
At Amazon, for $18.99, 45% under what the other stores charge, as of our latest check.
Where can I buy the Botanicare Cal-Mag Plus?
4 stores we checked sell it, including Cheap and Easy Hydro Store, HTG Supply, Amazon, Garden Dominion Supply.
1
Size
5 Gallon
Item Volume
1 Quart
Item Weight
2.2 lbs (1 kg)
Coverage Area
Full
Dimensions
7.5 INH (height)
Effect Speed
Promoting faster growth
Active Ingredients
Calcium, Iron, Magnesium
Ingredients
Magnesium, Calcium, Iron
Inactive Ingredients
Proprietary blend of select trace minerals
Container Size
2.5 Gallon
Container Type
Bottle
Packaging Size
1 Quart
Packaging Type
Bottle
Organic
No (Inorganic Based)
Eco-Friendly Certifications
Not OMRI certified
Sustainability Free Of
Non-GMO