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Calcium, Magnesium & Boron for Plants

Name: Calcium, Magnesium & Boron for Plants
Brand: GrowScripts
SKU: CMB9
Price: 12.99 USD
Availability: OutOfStock

$9.99

$8.99

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Size: 8-pack pre-measured packets

Product variants

When tomatoes, peppers, or squash get a sunken brown patch on the bottom of the fruit, that is blossom end rot, and it is a calcium problem. This Calcium supplement is the fix and the prevention: calcium plus magnesium and boron that strengthens cell walls, supports fruit set, and keeps calcium available to the plants most prone to running short. It comes two ways, so you can pick what suits you: a concentrate bottle you dose yourself for regular feeding across a collection, or pre-measured packets for grab-and-go simplicity with no measuring. Either way, use it alongside your regular fertilizer through the growing season.

Key features

Stops and prevents blossom end rot: supplies the calcium fruiting plants like tomatoes, peppers, and squash need.

Calcium, magnesium, and boron together: structure, fruit set, and green foliage in one supplement.

Fast uptake: nitrate-form calcium and magnesium the plant absorbs quickly.

Two formats, your choice: a dose-it-yourself concentrate bottle, or pre-measured grab-and-go packets.

Spray or drench, and a supplement: apply to soil or foliage, alongside your regular fertilizer.

Ingredients

Calcium (1.00%), from calcium nitrate, for cell walls and firm fruit.
Magnesium (0.10%), for chlorophyll and green foliage.
Boron (0.01%), which works with calcium for cell walls and fruit set.
Nitrate nitrogen (0.58%), which helps carry the calcium into the plant.

Same formula in both the bottle and the packets.

How to use

Choose your format, then apply to the soil as a drench or as a foliar spray, in addition to your regular fertilizer.

Concentrate bottle: shake well, mix 1 capful (5 mL, about 1 teaspoon) into 16 oz of water, or 2 capfuls (10 mL) into 32 oz. Apply monthly through the growing season, and more often during heavy fruiting.

Pre-measured packets: mix one packet (15 mL) into 64 oz, about half a gallon, of water. Apply every 2 to 4 weeks through the growing season.

For blossom end rot, apply through the fruiting period, and pair it with steady, even watering, which is the other half of the fix.

Why?

Blossom end rot and other calcium-deficiency symptoms often appear even when the soil has calcium, because the plant cannot move enough of it into the fruit fast enough, especially during heavy fruiting or uneven watering. A targeted calcium supplement puts calcium where and when the plant needs it, and the magnesium and boron round it out, magnesium for green foliage and boron for the cell walls and fruit set calcium supports. Because it is a supplement, it works alongside your main fertilizer rather than replacing it.

Makes how much?

The 8 oz concentrate bottle makes many gallons of finished feed when diluted to the label rate. The 8-pack has eight pre-measured packets, each making about half a gallon. Both provide regular calcium supplementation through a growing season.

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Frequently Asked Questions

What does calcium do for plants?

Calcium builds strong cell walls and firm tissue, which supports healthy growth and good fruit quality. When calcium runs short in the fruit, plants develop problems like blossom end rot on tomatoes and peppers, so keeping calcium available helps prevent them.

Will this help prevent blossom end rot?

Yes, it addresses the calcium side directly. It is worth knowing that blossom end rot is usually a calcium-uptake problem driven by inconsistent watering rather than a lack of soil calcium, so for the best results, pair this feed with steady, even watering, which is the other half of the fix.

Should I get the bottle or the packets?

Same formula, different format. The concentrate bottle lets you measure your own dose from a capful, the more economical and flexible choice if you feed calcium regularly or across many plants. The pre-measured packets are the grab-and-go option for occasional use with no measuring. Pick your format at the top of the page.

Why does it contain magnesium and boron?

Because the three work together. Boron helps calcium build cell walls and supports fruit set, and magnesium is central to chlorophyll and green foliage. Together they give more complete support than calcium alone.

What plants can I use it on?

Container fruit trees, tomatoes, peppers, squash and other vegetables, herbs, houseplants, and ornamentals, anywhere you want to prevent calcium-deficiency symptoms or support fruit set.

Can I use it with my regular fertilizer?

Yes, and you should. This is a calcium supplement meant to be used in addition to your normal fertilizer, not in place of it.

All about calcium, blossom end rot, and your plants

What blossom end rot really is

Blossom end rot shows up as a sunken, leathery brown patch on the bottom of tomatoes, peppers, squash, and other fruit, and it is a calcium problem, but usually not the one people expect. Most soil has plenty of calcium. The issue is that the plant cannot move calcium into the fruit fast enough, and the most common reason is uneven watering, since calcium travels with water through the plant. That is why the reliable fix has two parts: supply calcium, which this does, and water consistently so the plant can carry it to the fruit.

Why calcium, magnesium, and boron together

Calcium is the structural nutrient, building the cell walls that make tissue and fruit firm. Boron works right alongside it, helping form those walls and supporting flowering and fruit set, which is why the two are so often paired. Magnesium plays a different role, at the center of the chlorophyll molecule, keeping foliage green while the calcium and boron handle structure and fruit. Feeding them together covers more than calcium alone.

A supplement, used with your regular feed

This is not a complete fertilizer and is not meant to replace one. It is a targeted supplement for calcium, magnesium, and boron, used on top of your normal feeding during the season when fruiting plants are working hardest. If your main fertilizer already includes calcium, use this to top up during heavy fruiting or to correct a deficiency.

Bottle or packets: which format

Choose the 8 oz concentrate if you feed calcium regularly, across a collection, and want to control the dose and get more per dollar. Choose the pre-measured 8-pack if you want grab-and-go simplicity with no measuring for occasional use. Same formula, two ways to buy it, selectable at the top of the page.

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