Skip to main content

Send Us a Message

Search

Botanicare Cal-Mag Plus Supplements

$39.99 USD
  • 3.2% calcium and 1.2% magnesium for consistent mineral delivery
  • Iron and trace mineral blend acts as a catalyst for overall nutrient uptake
  • Concentrated 5 ml per gallon dosage works in soil, coco, and hydro
  • View More Details

Earn 29 points for shopping and get $0.29 off your next order. Join Harvest Club for free.

Questions? Talk to a specialist. Mon–Fri, 9am–5pm PST
Free Shipping On Most Items* To the lower 48
Transparent Pricing Backed w/ price match guarantee
4.8/5 Rating 1938+ verified reviews
Secure Checkout SSL encrypted payments

Send Us a Message

VOLUME PRICING

Commercial & Bulk Purchasing

We support operations & licensed facilities with volume pricing, dedicated account managers, and custom equipment consultation.

Commercial Inquiry

Contact Information
THROUGH THE Cultivator's LENS Hands-On Evaluation

Who This Is For

  • You are switching to coco coir because you want a faster growth cycle but need to compensate for its high mineral demand
  • You are adding a dedicated mineral supplement because your base nutrients alone cannot stop mid-cycle leaf yellowing

What We Found

  • Foliar application is the way to go if you need to stop a deficiency from spreading within 24 hours.
  • This formula stays stable in the reservoir and never leaves that thick residue that clogs small emitters.

What Users Say

  • Growers using RO water say they stopped seeing stunted growth once they added this to their base nutrients.
  • Users who moved to coco coir report fewer leaf spots after making this a permanent part of their regimen.

Botanicare Cal-Mag Plus

Seeing yellowing leaves between veins, stunted growth, or blossom end rot on your fruiting plants? These are telltale signs of calcium and magnesium deficiencies that can devastate yields if left uncorrected. Botanicare Cal-Mag Plus delivers a scientifically balanced blend of calcium (3.2%), magnesium (1.2%), and iron (0.1%) in optimal ratios to prevent these common deficiencies before they impact plant health. This targeted supplement is essential for growers using RO water, coco coir, or other low-calcium media where deficiencies develop rapidly in fast-growing crops.

Cal-Mag Plus functions as both a corrective treatment and preventative measure throughout the entire growth cycle. The fortified trace mineral blend acts as a catalyst, similar to the metabolic boost from Botanicare Liquid Karma Supplements, to enhance uptake of essential nutrients. This formula strengthens cell walls during the vegetative phase when used with Botanicare Pure Blend Pro Grow Nutrients, while supporting heavy fruit and flower development when paired with Botanicare Pure Blend Pro Bloom Nutrients. To maximize final harvest quality, many growers also integrate Botanicare Sweet Carbo Raw Supplement for enhanced aroma and flavor. At just 5 ml per gallon with every watering, this concentrated formula maintains consistent mineral availability without disrupting your base nutrient program.

Compatible with all nutrient lines and growing systems—hydroponics, soil, or containers—Cal-Mag Plus integrates seamlessly into any feeding schedule. Whether you're cultivating heavy-feeding annuals, managing a commercial cannabis operation, or growing vegetables in coco coir, this supplement provides the mineral foundation needed for vigorous vegetative growth and superior flower quality.

Features

🎯
Optimal Mineral Ratios

Precise 3.2% calcium, 1.2% magnesium, and 0.1% iron balance prevents deficiencies in all growth stages.

💧
Essential for RO & Coco

Critical supplement for reverse osmosis water and coco coir where calcium deficiencies develop rapidly.

🍅
Prevents Blossom End Rot

Eliminates calcium-related disorders in tomatoes, peppers, and reduces tip burn in lettuce crops.

Enhanced Nutrient Catalyst

Proprietary trace mineral blend increases uptake of essential nutrients for maximum yield potential.

🔄
Universal Compatibility

Integrates with any nutrient program in hydroponics, soil, or container systems without conflicts.

🌿
Dual Application Method

Use as root drench at 5 ml/gal or foliar spray at 10-15 ml/gal for rapid correction.

Specifications

Specification Value
Guaranteed Analysis 2.0-3.2-1.2 + 0.1% Iron
Nitrogen (N) 2.0%
Calcium (Ca) 3.2%
Magnesium (Mg) 1.2%
Iron (Fe) 0.1%
Available Sizes 1 Quart, 1 Gallon, 2.5 Gallon, 5 Gallon
Application Rate (Root Drench) 5 ml per gallon
Application Rate (Foliar) 10-15 ml per gallon
pH Range 6.2-7.0
Suitable For Hydroponics, Soil, Containers, Coco Coir
Ideal Crops Cannabis, Tomatoes, Peppers, Lettuce, Fruiting Plants

Support & Manuals

Frequently Asked Questions

When should I use Cal-Mag Plus in my feeding schedule?+

Use Cal-Mag Plus with every watering throughout the entire growth cycle, from seedling through harvest. Add 1 teaspoon (5 ml) per gallon of water, mix thoroughly, and adjust pH to 6.2-7.0 before application. For young plants, establishing a strong root system with Botanicare Rhizo Blast Root Stimulator ensures they can efficiently utilize these minerals. Shake the bottle well before each use.

Why is Cal-Mag Plus essential for RO water and coco coir?+

Reverse osmosis water removes beneficial minerals including calcium and magnesium, while coco coir naturally binds calcium, making it unavailable to plants. Without supplementation, fast-growing crops quickly develop severe deficiencies. To maintain a healthy root zone in these conditions, many professionals also incorporate Botanicare Hydroguard Root Inoculant alongside their Cal-Mag regimen.

How does Cal-Mag Plus prevent blossom end rot?+

Blossom end rot in tomatoes and peppers is caused by calcium deficiency during rapid fruit development. Cal-Mag Plus provides immediately available calcium that prevents the characteristic dark, sunken spots on fruit bottoms. Consistent application throughout the flowering and fruiting stages maintains adequate calcium levels for proper cell wall development.

Can I use Cal-Mag Plus as a foliar spray?+

Yes, foliar application delivers rapid correction of visible deficiency symptoms. Mix 10-15 ml per gallon of water and spray directly onto foliage for faster uptake through leaves. This method is particularly effective for quickly addressing interveinal chlorosis or when plants show acute deficiency symptoms between regular feedings.

Will Cal-Mag Plus work with my current nutrient line?+

Absolutely—Cal-Mag Plus is formulated for universal compatibility with any base nutrient program. The low NPK ratio and balanced mineral content complement rather than compete with your existing feeding schedule. Many growers use it alongside Botanicare Pure Blend Pro Grow Nutrients or other preferred programs without experiencing nutrient lockout or imbalances.

How do I know if my plants need Cal-Mag supplementation?+

Common deficiency symptoms include yellowing between leaf veins (interveinal chlorosis), brown spotting on leaves, stunted growth, and weak stems. If stems are weak or brittle, adding Botanicare Silica Blast Supplements can help improve plant rigidity. If you're using RO water, LED lighting, or coco coir, preventative supplementation is recommended regardless of visible symptoms.

Which size should I purchase for my grow setup?+

The 1 quart size covers hobbyist grows with 2-6 plants for several weeks, while the 1 gallon suits medium operations with 10-15 plants. Commercial growers or those running perpetual harvests should consider the 2.5 or 5 gallon options for better value—at 5 ml per gallon per watering, larger sizes significantly reduce per-application costs and reorder frequency.

Happy To Help

Questions About This Product?

Our specialists are happy to help. Call us or send a message and we'll get back to you within one business day (most of the time within a few hours.)

Call (360) 800-5535

Why Trimleaf

Equipping home growers, craft producers, and commercial operations across North America since 2016.

10+
Years of Specialist Knowledge
4.8★
Over 1,900 Verified Reviews
50,000+
Growers Served
120+
Top Equipment Brands in Stock