Top 10 Cal-Mag for Hydro Gardens in 2026: Healthy Growth

General Hydroponics CALiMAGic is a concentrated calcium and magnesium supplement with an NPK of 1-0-0. It is designed for hydroponic, coco coir and soil growers feeding fast growing plants, especially tomatoes, peppers and leafy greens.

The formula delivers readily available calcium and magnesium to prevent secondary deficiencies before they stunt growth. In real world use, it helps stop blossom end rot and tip burn while supporting stronger stems, healthy foliage and better fruit formation.

The solution is clean, fully soluble and reservoir friendly, so it will not clog spray lines or drip emitters. It mixes smoothly with many base nutrients, which makes it easy to add to existing feeding schedules without extra hassle.

As a supplement, it is not a complete fertilizer and needs a base nutrient program to work correctly. Dosing also requires care, since over application can interfere with uptake of potassium and other key elements.

For indoor and outdoor growers battling calcium issues, CALiMAGic is a reliable, easy to use fix. It is concentrated, versatile and ideal for anyone growing calcium intensive vegetables in hydroponics or coco.

Brand: General Hydroponics, Model: HGC733525, Form: Liquid concentrate, NPK 1-0-0.

Size: 32 fluid ounces quart, Mixing ratio 1:1000, Use: Hydroponics, coco coir and soil.

Target crops: Tomatoes, lettuce and other calcium intensive vegetables, System safe for reservoirs, drip emitters and spray lines.

Use CALiMAGic as a supplement alongside your base nutrient program, not as a standalone fertilizer. Start with the label rate and adjust based on plant response and water quality.

It can be added to reservoirs or applied as a foliar spray, and it stays soluble without clogging equipment. Shake well before use and monitor EC and pH for best results in hydroponic systems.

TPS Nutrients Cal Mag for Plants is a liquid calcium and magnesium supplement enhanced with iron and micronutrients. It is designed for indoor houseplants, hydroponic systems, coco coir and outdoor vegetable gardens, especially tomatoes.

Its standout formula delivers readily available calcium and magnesium to support strong structure and steady development. Growers report greener leaves, less yellowing and noticeably vigorous growth when used regularly in coco and soil.

The liquid concentrate mixes easily at a 1:100 ratio and fits cleanly into existing feeding schedules. Made in the USA, it offers consistent quality and full coverage feeding for containers, soil beds and hydro reservoirs.

The main limitation is the 8 fluid ounce size, which is best for small grows and trial use. Like all supplements, it needs consistent application and correct measuring, as it will not instantly correct long term deficiencies.

For anyone growing in coco, hydroponics or nutrient hungry vegetables, this is a simple and effective addition. It supports balanced nutrition, stronger plants and more resilient growth with minimal effort.

Brand: TPS NUTRIENTS, Model: GARDCALMAG8OZ, Form: Liquid concentrate for plant growth.

Size: 8 fluid ounces, Mixing Ratio: 1:100, Coverage: Full, Target: All plants.

Use: Soil, coco coir, containers, indoor plants, garden beds and hydroponic systems.

Highlights: Calcium, magnesium, iron and micronutrient formula to help reduce yellowing leaves, ideal for tomatoes and vegetables.

Athena Blended CaMg is a liquid cal-mag supplement with NPK 2-0-0, combining calcium, magnesium, iron and nitrogen for soilless growing. It is built for hydroponic, coco coir, rockwool and RO water gardeners, plus container and indoor growers of vegetables and flowers.

Its standout benefit is continuous replenishment of calcium and magnesium that hydro systems and coco deplete quickly. In real world use, growers report greener foliage, stronger stems and cleaner fruit set, with fewer signs of blossom end rot, tip burn and chlorosis during flowering.

The formula uses a balanced calcium to magnesium ratio to improve nutrient uptake and stress resistance without complicating your feed schedule. As a liquid concentrate, it mixes cleanly and works alongside any base nutrients through hand watering, drip irrigation, Dosatron and automated dosing.

The main limitation is that it is a supplement, not a complete fertilizer, so base nutrients are still required for full growth. The 32 fluid ounce bottle suits tents and small gardens well, but larger operations will need to reorder often and measure carefully.

Overall, Athena CaMg is a professional grade, simple to use solution for preventing deficiencies that stall growth in soilless systems. If you grow tomatoes, peppers, berries or other fruiting plants in hydro, coco or RO water, it is a reliable addition for healthier plants and more consistent harvests.

Brand: Athena, Line: Blended CaMg Cal-Mag Fertilizer, NPK 2-0-0

Form: Liquid concentrate, 32 fluid ounces, with calcium, magnesium, iron and nitrogen

Use: Hydroponic gardening, coco coir, rockwool, RO water, container and indoor growing

Application: Drip feed, hand watering, Dosatron and automated dosing, use alongside base nutrients

Crops: Tomatoes, peppers, vegetables, berries, flowers and other heavy feeding fruiting plants

Use Athena CaMg throughout the vegetative and flowering stages when calcium and magnesium demand is highest. It is especially helpful for RO water and coco grows that lose these elements quickly.

Add to water before base nutrients to ensure even mixing and availability, then pH as needed for your system. Follow label directions and adjust frequency based on plant response.

Watch for tip burn, leaf chlorosis, weak stems or poor fruit development as signs to supplement. Consistent low dose use often works better than correcting a severe deficiency later.

Compatible with hand watering, drip lines and automated dosing for steady feeding in hydro, coco and rockwool setups.

FoxFarm Bush Doctor Cal Mag is a liquid calcium and magnesium supplement designed for organic gardeners, indoor growers, and fruit and vegetable producers. It is ideal for anyone seeing signs of deficiency or wanting to prevent blossom end rot and tip burn before they start.

The 1-0-0 formula delivers 3% calcium and 0.9% magnesium to strengthen cell walls and support healthy fruit development. Used weekly at 1 tsp per gallon starting before bud development, it helps keep plants resilient through heavy growth and fruiting stages.

As a liquid concentrate in a 16 oz pint, it measures easily, mixes cleanly, and fits well in small grow rooms and home gardens. Being OMRI listed and greenhouse tested by FoxFarm since 1984, it offers consistency growers can rely on for organic programs.

It is a supplement, not a complete fertilizer, so it works best alongside your base nutrients and with pH kept between 5.6 and 6.8 for uptake. Large gardens will go through the pint quickly, and weekly applications require a consistent routine.

For gardeners who want stronger plants and cleaner fruit without synthetic additives, this is a simple and trusted solution. If you grow tomatoes, peppers, or calcium hungry plants, Bush Doctor Cal Mag is an easy addition worth keeping on hand.

Brand: FoxFarm, Model Number: FX17010, Size: 16 Fluid Ounces (1 Pint)

Analysis: 1-0-0 with 3% Calcium and 0.9% Magnesium, Form: Liquid concentrate

Use: Supplement for calcium and magnesium deficiency in organic gardening, Mix Rate: 1 tsp per gallon weekly

General Hydroponics GH5312 CaMg+ is a liquid calcium and magnesium supplement designed for hydroponic growers, coco coir users and anyone using RO water. It is made for plants showing signs of deficiency or for heavy feeding varieties that need extra support during growth and bloom.

Its standout feature is the biologically catalyzed blend of fermented calcium and magnesium with organic acids and sugar chelates. In real world use, this focus on transport and uptake helps maintain green, healthy foliage and supports more robust flowering and fruiting.

The formula comes as a clean mixing liquid in a 32 oz quart bottle that fits easily into most feeding schedules. Build quality is consistent with General Hydroponics standards, with a stable concentrate that blends well with base nutrients without excess residue.

As a targeted supplement, it will not replace a complete nutrient program and dosing needs attention. Beginners may need to start low and monitor EC and pH, especially in small reservoirs where minerals can build up quickly.

Overall, CaMg+ is a reliable, grower trusted solution for preventing common calcium and magnesium issues. If you grow in hydroponics or coco and want healthier plants with better blooms, it is a smart addition to your lineup.

Brand: General Hydroponics, Model: GH5312, Form: Liquid concentrate, Volume: 32 fluid ounces (946 ml).

Use: Hydroponics and plant nutrition, Target: Calcium and magnesium supplementation for flowers, fruits and vegetative growth.

Includes: 1 quart bottle of CaMg+ Hydroponic Plant Supplement, Item Weight: 1.2 pounds.

TPS Nutrients Cal-Mag Complete is a liquid calcium and magnesium supplement made for soil, coco and hydroponic growing. It is built for indoor gardeners, hydro growers and outdoor vegetable gardeners who want stronger, more balanced plants.

Its standout benefit is improved nutrient uptake efficiency to support steady growth and stability. In real world use, it helps correct common micronutrient deficiencies and supports tomatoes and peppers prone to blossom end rot.

The formula comes as an easy to mix liquid concentrate with a 1:200 mixing ratio for full coverage feeding. The 32 ounce bottle is compact, lightweight and simple to measure, pour and store.

As a targeted supplement, it does not replace a full fertilizer program and needs accurate dosing. Larger gardens may go through the bottle faster than expected with regular feeding.

Overall, Cal-Mag Complete is a reliable, USA made solution for preventing deficiencies and supporting healthy development. If you grow tomatoes, peppers or hydroponic plants, it is a smart addition to your routine.

Brand: TPS Nutrients, Form: Liquid concentrate, Size: 32 fluid ounces

Use: Soil, coco, hydroponics and indoor plants, Target: General plants, tomatoes and peppers

Mixing Ratio: 1:200, Item Weight: 2 pounds, Part Number: TRUECMC1Q

Botanicare Cal-Mag Plus is a liquid calcium, magnesium and iron supplement with a 2-0-0 NPK, made to fill nutritional gaps in modern growing methods. It is built for indoor and outdoor growers using reverse osmosis water, coco coir, containers, soil or hydroponic systems.

In real world use, it excels at preventing and correcting classic deficiency signs like interveinal yellowing, weak stems and slow growth. Growers appreciate that it can be added to every watering for maintenance or used as a foliar spray for faster uptake when plants show stress.

The formula comes as a concentrated liquid in a 32.36 fluid ounce quart bottle that mixes cleanly at a low dilution ratio. It blends easily without heavy residue and layers well with most existing nutrient programs, which makes routine feeding simple and consistent.

It is not a standalone fertilizer, so you will still need a complete base nutrient for flowering and overall nutrition. As with any concentrated supplement, dosing accuracy matters since too much calcium or nitrogen can lock out other nutrients.

Overall, Cal-Mag Plus remains a go to staple for coco, hydro and RO growers who want healthier roots, stronger vegetative growth and fewer deficiency surprises. If you grow in calcium hungry media, this is a practical and proven addition to your routine.

Shake well and mix Cal-Mag Plus with water according to your plant stage and base nutrient schedule. It is designed for use with every watering as needed to maintain healthy calcium and magnesium levels.

For faster correction, it can also be applied as a foliar spray to deliver minerals directly to leaves. Always mix thoroughly, apply evenly for full coverage, and monitor plants for improved color and vigor.

Brand: Botanicare, Model: HGC732110, Part Number: BCCMQT. Item Form: Liquid concentrate, Volume: 32.36 fluid ounces quart, NPK: 2-0-0.

Supplements: Calcium, magnesium and iron for plant growth, root development and soil conditioning. Application: Drench with watering or foliar spray. Use Sites: Containers, soil, coco coir and hydrogardens.

Botanicare Cal-Mag Plus 2-0-0 is a fortified calcium, magnesium and iron supplement designed to correct common nutrient deficiencies. It is made for indoor, hydroponic and coco coir growers, especially those using reverse osmosis water that strips essential minerals.

Standout performance comes from its fortified 2-0-0 blend that supports vigorous growth in veg, transition and bloom. Growers report greener foliage, stronger stems and faster recovery from yellowing, with noticeable results when buffering coco or recharging depleted soil.

The liquid concentrate mixes easily into existing nutrient programs and can also be applied as a foliar spray for rapid uptake. The quart bottle is sealed for freshness, lightweight for handling, and simple to measure for consistent feeding.

It is not a standalone fertilizer, so you will still need base nutrients for complete feeding. Large gardens may go through the quart quickly, and overuse can throw off nutrient balance, so careful dosing is important.

For anyone growing in coco coir, RO water or intensive containers, this is a must have supplement. It delivers reliable deficiency correction, flexible use and expert backed quality that helps produce healthier, more productive plants.

Brand: Botanicare, Model: HGC00023, Formula: 2-0-0 calcium, magnesium and iron liquid supplement.

Size: 1 quart liquid concentrate for root drench or foliar spray use.

Best for: Coco coir media, reverse osmosis water systems, and container plants in veg through bloom.

TPS Nutrients Organic Cal-Mag OAC is a liquid calcium and magnesium supplement designed for soil, coco coir and hydroponic growers. It is built for indoor plants, gardens and heavy feeding programs where deficiencies show up fast, especially in coco and high intensity setups.

Its standout feature is a nitrogen-free formula with added iron and micronutrients for better uptake. Growers report steady growth, stronger structure and quick correction of calcium and magnesium issues, with many calling it more effective than standard synthetic cal mag options.

The 32 oz liquid concentrate mixes cleanly at 5 to 10 ml per gallon and fits easily into existing feeding schedules. Made in the USA for organic growing, it pours smooth, dilutes well and works alongside other nutrients without adding extra nitrogen.

The main tradeoff is a distinct vinegar-like smell from the organic formulation, which fades once mixed with water. Some users also find they need the higher end of the dose range when using it as a standalone source of calcium and magnesium.

For coco, hydro and heavy feeders that need clean calcium plus micros, this is an excellent pick. If you want an organic, versatile and nitrogen-free cal mag that performs consistently, it earns a strong recommendation.

Brand: TPS Nutrients, Model: TPSCMOAC1Q, Form: Liquid concentrate for soil, coco coir and hydroponics.

Size: 32 fluid ounces, Mix Rate: 5 to 10 ml per gallon, Use: Organic growing for all plant types.

Highlights: Nitrogen-free calcium and magnesium with iron and micronutrients, Made in USA.

The VIVOSUN Cal+Mag+Iron (2-0-0) is a targeted calcium, magnesium and iron supplement made for gardeners dealing with nutrient deficiencies. It is designed for indoor tent growers, hydroponic users, and outdoor vegetable and houseplant enthusiasts who need stronger foundational nutrition.

Its standout benefit is the 3-in-1 blend that tackles yellowing between veins, tip burn and poor fruit development in one step. The added nitrogen supports leafy vegetative growth, while magnesium and iron help maintain deep green color and efficient photosynthesis.

The product comes in a sturdy 32oz bottle that is compact, easy to pour and simple to store with other nutrients. At just over 2.5 pounds, it feels substantial without being bulky, and the concentrated formula allows for small, controlled doses.

As with most Cal Mag products, results depend on correct dosing and it will not replace a full base fertilizer program. Growers with very large gardens may find the bottle size limiting, and beginners should start light to avoid over application.

Overall, VIVOSUN Cal+Mag+Iron is a practical, high performing supplement for anyone growing in coco, hydro or depleted soil. If you want greener leaves, stronger stems and better resilience, this is a smart addition to your feeding routine.

Brand: VIVOSUN, Model: VSN-CAMGIR32, Size: 32oz Cal Mag Iron supplement with 2-0-0 formula.

Package Dimensions: 7.44 x 5.2 x 2.2 inches, Weight: 2.56 pounds for easy handling and storage.

Category: Fertilizers and Plant Food for soil, coco coir and hydroponic use.