FoxFarm Bush Doctor 1-0-0 Cal-Mag Supplement | 16oz - 3% Calcium - 0.9% Magnesium - OMRI Listed - (Case of 12)

OMRI-Listed Calcium and Magnesium Supplement for Heavy-Feeding Crops, 16oz

Heavy-feeding crops in fast-draining soilless mixes or high-EC hydroponic programs can pull through calcium and magnesium reserves faster than a base nutrient line replaces them, showing up as blossom end rot on fruit or tip burn on new leaves. FoxFarm Bush Doctor Cal-Mag 1-0-0 is a 3% calcium, 0.9% magnesium supplement built to close that gap, and it carries both OMRI Listing and CDFA registration for certified organic programs.

The 16oz case of 12 is a compact retail size for shops offering Cal-Mag.

Key Features & Benefits

• 3% calcium, 0.9% magnesium — targets the two secondary macronutrients most likely to run short under heavy feeding.
• OMRI Listed and CDFA Registered — eligible for use in certified organic cultivation programs.
• 1-0-0 formula — calcium-forward with no phosphorus and no added potassium, so it layers onto an existing feeding program without skewing the base NPK.
• Deficiency-targeted — aimed at correcting symptoms like blossom end rot and tip burn rather than general-purpose feeding.

Who Should Use Bush Doctor Cal-Mag

Growers running heavy-feeding crops in coco, rockwool, or other fast-draining media, or anyone seeing blossom end rot or tip burn symptoms, are the fit for a dedicated calcium-magnesium supplement like this one.

About Fox Farms

FoxFarm's Bush Doctor line, produced out of Humboldt County, California since the company's 1984 founding, covers targeted supplements like Cal-Mag alongside the brand's broader soil and liquid feeding programs.

Frequently Asked Questions

What calcium and magnesium levels does Bush Doctor Cal-Mag provide?

It supplies 3% calcium and 0.9% magnesium in a 1-0-0 formula with no added phosphorus or potassium. That leaves it free to layer onto whatever base feeding program is already running.

Is this Cal-Mag supplement certified for organic growing?

Yes, it carries both OMRI Listing and CDFA registration, making it eligible for certified organic cultivation programs. That holds across all three package sizes.

What deficiency symptoms does Cal-Mag address?

Blossom end rot on fruiting crops and tip burn along leaf margins are the two most common signs of a calcium or magnesium shortfall that this supplement is built to correct. Both tend to show up under heavy feeding in fast-draining media.

How does Cal-Mag fit into my existing nutrient program?

It's designed to be added into an existing feeding schedule rather than replace it, since the 1-0-0 ratio doesn't add phosphorus or potassium that could throw off an established program. Check the FoxFarm feeding schedule for suggested rates.