Finally, a garden amendment focusing on plant available Calcium & Magnesium! Blended from only premium, (majority) ocean derived ingredients, growers can now provide their plants with a fast & slow release source of Cal Mag! Perfect for adding to Living Soils & for Cactus & Succulent Gardening.
Calcium is a vital nutrient that is responsible for providing plants with the ability to build strong and healthy cell walls. This is especially important for young plants, as they need sturdy cell walls to support their growth and development. In addition, calcium helps to regulate the movement of other nutrients within the plant, which ensures that they are distributed evenly throughout the plant's tissue.
Magnesium is another essential nutrient that plants require in order to thrive. This nutrient is responsible for the production of chlorophyll, which is necessary for photosynthesis. Photosynthesis is the process by which plants convert sunlight into energy, so it is clear that magnesium plays a critical role in the plant's ability to harness the power of the sun. Additionally, magnesium helps to regulate other important processes within the plant, such as the activation of enzymes.
Ocean Grown Calcium Magnesium Blend can be use in place of garden lime to add MANY more trace elements to your soil! It will raise the pH of your soil.
Usage guide
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Existing Soils - Use 1 tablespoon per 10L of soil. Make sure to turn into the soil and water in immediately. Use monthly.
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Making a Liquid Extract - Use 1 tablespoon per 5L of water. Prefferably bubble overnight using a compost brewer.
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New Soils - Use 1/2 to 1 cup per 30L of new potting soils.
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Garden Beds - Use 1-2 cups per m2 once per year.
Ingredients - Black Basalt Rock Dust, Glacial Rock Dust, Fish & Bone Meal, Kelp Meal, Fish Meal, Oyster Shell, Leonardite
FAQs:
What is Ocean Grown Cal-Mag?
It’s a dry, ocean-inspired calcium and magnesium amendment for soils. Think of it as a slow + steady mineral top-up for living soils, raised beds, pots, and even cactus/succulent mixes.
What’s in the Ocean Grown Cal-Mag?
It’s a dry, ocean-inspired calcium?
Black basalt rock dust, glacial rock dust, fish & bone meal, kelp meal, oyster shell, and leonardite.
What does the Ocean Grown Cal-Mag actually do for my plants?
Calcium builds strong cell walls and supports nutrient movement; magnesium sits at the core of chlorophyll (photosynthesis). Together they help prevent weak stems, tip burn, blossom end rot, interveinal chlorosis (yellowing between veins), and general “tired” growth.
Is the Ocean Grown Cal-Mag just “garden lime” with a fancy label?
No. You can use it instead of garden lime, but this blend brings extra trace minerals and both fast + slow release forms, not just calcium carbonate.
Will the Ocean Grown Cal-Mag raise my soil pH?
Yes—moderately and over time. Oyster shell and other alkaline inputs nudge acidic soils upward. Don’t overdo it if your soil is already neutral to alkaline.
How fast does the Ocean Grown Cal-Mag work?
You’ll get some quicker release from fish/bone and kelp, with long-tail release from oyster shell and rock dusts. Expect a gentle climb in plant vigor over weeks, not an overnight miracle.
How do I use the Ocean Grown Cal-Mag on existing pots or beds?
Top-dress 1 tablespoon per 10L of soil, scratch it in lightly, and water in. Repeat monthly if needed.
How do I use the Ocean Grown Cal-Mag when mixing new soil?
Blend ½–1 cup per 30L of fresh potting mix at build time.
How much for garden beds?
1–2 cups per square meter, once a year, worked into the top layer and watered in.
Can I make a liquid “tea” with the Ocean Grown Cal-Mag?
Yep. 1 tablespoon per 5L of water, ideally bubbled overnight for extraction. Water in well.
Is the Ocean Grown Cal-Mag safe for living soil and microbes?
Yes. It’s designed for living soils and won’t nuke your biology. It’s a mineral/organic blend, not a harsh salt.
Will the Ocean Grown Cal-Mag mess with my EC like bottled Cal-Mag can?
Much less. This is a dry amendment that integrates with the soil food web. It’s not a high-salt, immediate EC spike like many liquids.
I grow succulents and cacti—worth using?
Definitely. Calcium and magnesium support firm tissue and balanced growth. Use sparingly and watch pH in gritty, alkaline mixes.
Can I overdo the Ocean Grown Cal-Mag? What does “too much” look like?
Yes—especially in already alkaline media. Signs can include stalled growth, leaf tip issues, or induced Mg unavailability if calcium is over-supplied. If you’ve gone heavy, pause further liming inputs, add compost, and water normally.
Does the Ocean Grown Cal-Mag fix blossom end rot in tomatoes/peppers?
It helps address the calcium availability side of that problem. Still keep watering consistent—fluctuating moisture is the other major cause.
What deficiency symptoms suggest I should add Cal-Mag?
For magnesium: yellowing between leaf veins (often on older leaves first).
For calcium: twisted new growth, weak stems, tip burn, blossom end rot, poor flower set. Confirm pH and watering before you blame nutrients.
Do I still need dolomite lime?
Usually no. This blend covers calcium and provides mineral-derived magnesium. Avoid stacking multiple liming agents unless a soil test tells you to.
Is the Ocean Grown Cal-Mag okay with coco or hydro?
This product is a soil amendment. In coco/hydro, you generally use a liquid Cal-Mag in the feed. If you’re running soil-less mixes with organics, use it sparingly and monitor pH.
Can I use the Ocean Grown Cal-Mag with my usual organic amendments and compost teas?
Yes. It plays nicely with composts, worm castings, and most organic feeds.
Will the Ocean Grown Cal-Mag burn my plants?
Not when used at the listed rates. It’s gentle compared to soluble salts.
When in the plant cycle should I apply the Ocean Grown Cal-Mag?
Anytime in veg or early flower for most annuals. For perennials/houseplants, monthly light top-dressings are fine. Avoid big pH-shifting applications late in flower.
How often do I reapply?
For pots: monthly light top-dress is the simple rule. For beds: 1–2 cups/m² once a year is plenty unless a soil test says otherwise.
Can I foliar spray the Ocean Grown Cal-Mag?
No—this isn’t a foliar product. If you want a fast magnesium bump via foliar, use a light Epsom salt spray (in soil grows). Keep Ocean Grown Cal-Mag in the soil.
Does the Ocean Grown Cal-Mag help heavy feeders (tomatoes, brassicas, peppers, flowering annuals)?
Yes. Those crops all pull significant calcium and benefit from steady magnesium.
Any interactions I should know about?
Don’t stack with other liming minerals (dolomite, oyster shell, hydrated lime) unless you know your soil pH and base saturation. Too much calcium can make magnesium less available.
What about houseplants and tropicals?
Use lightly (1 tbsp per 10L soil, monthly). Great for long-term resilience, but keep an eye on pH in premium potting mixes.
Is the Ocean Grown Cal-Mag pet-safe?
It’s a soil amendment made from natural mineral/organic inputs. Keep out of reach of pets and children, and store sealed—standard common sense.
What’s the shelf life?
Indefinite if kept dry and sealed. Minerals don’t expire; they just clump if they pick up moisture.
How should I store the Ocean Grown Cal-Mag?
Cool, dry place, bag sealed. If it clumps, break it up before applying.
I already added a bunch of lime this season—can I still use the Ocean Grown Cal-Mag?
If you’ve limed heavily, hold off. Get a simple soil pH test first. If you’re already at ~6.5–7.2, skip more liming inputs until next season.
Will the Ocean Grown Cal-Mag change the taste or quality of my fruit/veg?
Balanced Ca/Mg usually improves texture (fewer watery/bland fruits), reduces physiological disorders, and supports consistent yields.
Is the Ocean Grown Cal-Mag certified organic?
It’s made from natural and mineral inputs. If you require a specific certification mark, check the bag or product page before purchase.
Any quick application tips?
Top-dress, scratch in lightly, and water to activate. Go light and frequent rather than heavy once. In new mixes, pre-blend thoroughly.
My soil pH is low (acidic). Should I use the high end of the rate?
Yes—start closer to the higher end for new soils/beds. Re-test after a few weeks before adding more.
My soil is already alkaline. Should I use the Ocean Grown Cal-Mag?
Use sparingly or skip it. You’ll get more mileage from compost and balanced feeds; only add Ca/Mg if a test shows you’re short.
Can I combine the Ocean Grown Cal-Mag with Epsom salts?
If you specifically need a fast magnesium hit, you can use a light Epsom foliar or drench. Don’t stack big soil doses of Epsom and this product repeatedly—balance matters.
Does the Ocean Grown Cal-Mag help with nitrogen fixation in legumes?
Adequate calcium supports healthy root nodules, which is good news for peas/beans. It won’t replace inoculants or proper soil biology, but it sets the stage.
What size bags does the Ocean Grown Cal-Mag come in and what do they cover?
1kg and 2.5kg. As a rough guide:
• Pots: 1 tbsp per 10L of soil per month goes a long way.
• Beds: 1–2 cups per m² annually means 1kg covers ~6–12 m², depending on rate.
Bottom line: who is the Ocean Grown Cal-Mag for?
Soil growers who want a calmer, steadier Cal-Mag supply that plays nice with living soil—veggies, flowers, fruiting crops, houseplants, succulents. If you’re in coco/hydro, use a liquid Cal-Mag instead. 
