ENVY CalMag+ Fe (4-0-0) Professional Grade Liquid Plant Food

In this review of ENVY CalMag+ Fe (4-0-0), the bottom line is simple: growers using reverse osmosis water, coco-coir, or hydroponic systems will appreciate a concentrated, plant-friendly calcium source that avoids calcium chloride. The reviewer found this formula especially useful for preventing blossom end rot in tomatoes and peppers and for correcting nutrient lock up in coir, making it a practical supplemental product for growers who need reliable calcium, magnesium and iron without upsetting their base nutrient program.

Key Features

• Superior Cal-Mag source: Calcium is supplied as calcium nitrate rather than calcium chloride, which reduces the risk of chloride buildup and is gentler on hydro systems.
• Formulated for R.O. water: Designed to replenish minerals stripped by reverse osmosis, restoring calcium and magnesium levels for healthier plant growth.
• Prevents blossom end rot: Provides highly absorbable calcium to tomatoes and peppers to reduce the leaf yellowing and fruit rot caused by calcium deficiency.
• Corrects coir lock up: Concentrated formulation helps replace nutrients that become bound in coco-coir fibers so plants can access them again.
• Compatible with nutrient lines: Works alongside hydroponic, soil and coir nutrient systems and performs best when paired with ENVY A & B base nutrients.

Who It's For

This product is aimed at hobbyist and professional growers who use reverse osmosis water, hydroponic systems, or coco-coir and need a dependable supplemental source of calcium, magnesium and iron. Home gardeners growing tomatoes, peppers or other fruiting crops will benefit from its ability to prevent blossom end rot and correct nutrient lock up.

Growers who already have balanced mains water and do not see signs of calcium deficiency may not need a concentrated CalMag supplement. Those seeking a complete base nutrient should treat this as a supplement rather than a replacement for core A & B nutrient lines.

Pros & Cons

Pros

• Provides calcium as calcium nitrate, which is gentler on plants and hydro systems.
• Effective at preventing blossom end rot in tomatoes and peppers when deficiency is the cause.
• Replenishes minerals removed by R.O. water and helps free nutrients locked in coco-coir.
• Customers report good value, ease of use and measurable plant health improvements.

Cons

• Sold as a supplement, so growers still need a compatible base nutrient regimen for complete feeding.
• Concentrated formula requires careful dosing to avoid over-application.

Specifications

Product type	Liquid CalMag supplement
N-P-K	4-0-0
Key minerals	Calcium (as calcium nitrate), Magnesium, Iron
Intended use	Hydroponic, soil and coco-coir supplementation
Compatibility	Works with all nutrient lines; optimal with ENVY A & B
Primary benefit	Prevents blossom end rot and corrects nutrient lock up

Our Verdict

ENVY CalMag+ Fe (4-0-0) is a focused supplemental product that delivers plant-friendly calcium and supporting minerals without calcium chloride, making it a smart choice for R.O. users, coir growers and anyone fighting blossom end rot. It pairs best with a complete base nutrient system and offers solid value for growers who need a reliable CalMag boost.

Frequently Asked Questions

Can this be used with reverse osmosis water?
Yes. It is formulated specifically to replace minerals stripped by R.O. systems and restore calcium and magnesium levels.

Will it prevent blossom end rot in tomatoes?
When blossom end rot is caused by calcium deficiency, supplying absorbable calcium as in this formula helps prevent and correct the condition.

Is it compatible with other nutrient brands?
Yes. It works with most hydroponic, soil and coir nutrient lines but is recommended as a supplement alongside a complete base nutrient program.