Calnesium: Calcium & Magnesium Supplement

Brand: Future Harvest

Product Code: 0700073

Availability:In stock

$18.99 18.99

Available Options


Calnesium 2-0-0 is a powerful calmag booster that'll increase both Calcium and Magnesium availability to your plants when added to your feed program.

Calnesium's calmag formula is a strong blend of Nitrogen, Calcium, and Magnesium that is specifically designed to provide an additional nutrient boost to our Future Harvest Holland Secret 3 Part fertilizer. Also, it is an excellent calmag additive to prevent end rot on tomatoes and peppers.

Calnesium is 100% compatible with all high quality nutrients as it's calmag formula mixes quickly and easily. Calcium, Magnesium, and Iron are incredibly important to photosynthesis (making energy from light) and maintaining the structure of the plant. Calnesium works as part of your feed program and as a foliar spray



Available sizes shown from 500mL, 1L, 4L, 10L, 20L, 208L, totes of Calnesium

Key Features: 

  • Calnesium's calmag formula is designed to be used with Holland Secret Grow and Micro.
  • Inhibits blossom end rot by providing additional Calcium and increasing nutrient uptake. 
  • Strengthens plant cells and tissues for increased resistance to stress
  • Increases cell division and plant tissue development. 
  • Increases flower and fruit sets. 
  • Increases water, nutrient, and carbon dioxide uptake. 



Future Harvest Calnesium Guaranteed Analysis

Product Comparison

  • General Hydroponics: CALiMAGic
  • Green Planet: Pro Cal
  • GroTek: Cal-Max
  • Emerald Harvest: Cal-Mag









    Customer Reviews

    Based on 5 reviews Write a review


    The Future Harvest online store ships all over Canada and the United States from Canada. We also have a distributor in the United Kingdom, The Growers Wholesale. CLICK HERE for a list of our distributors. 

    All orders are processed within 1 business day.

    Your order will be marked as fulfilled from the moment it’s been boxed up in the warehouse awaiting for the courier to pick it up. Once your order has been fulfilled, you will receive an email with your tracking number. Your tracking details will appear once the courier has processed the package.

    We deliver packages through the following couriers: Canada Post, UPS, Canpar, and Purolator. The courier will be chosen based on the fastest estimated shipping time. 

    We currently only ship to PO Boxes across Canada via Canada Post. If you enter a PO box for a US order, we will contact you to provide an alternative delivery address.





    In Canada, we offer free shipping over $100 CAD before tax. In the United States, we offer free shipping over $150 CAD. 



    All Future Harvest online orders will be shipped out in branded boxes. If you would like discreet shipping, simply request for it in the shipping notes section on the cart page. 



    Shipping Times
    British Columbia 
    2-3 business days 
    & Manitoba 
    3-5 business days 
    Ontario, Quebec,
    Newfoundland & Labrador,
    & PEI 
    3-7 business days 
    USA 7-15 business days 



    Nutrients can freeze when exposed to cold temperatures. We protect your packages by shipping liquid nutrients with heat packs and faster shipping methods during the winter months. Depending on courier, your package may not be sent out until the following Monday to ensure it does not sit in a cold warehouse over the weekend. If your nutrients freeze, simply mix the entire bottle with an equal amount of hot water (preferably reverse osmosis or distilled water) and double your dosage. For detailed information CLICK HERE

    Occasionally, our online inventory is inaccurate. In the case we cannot fulfill your order due to an item being out of stock, we will contact you within 24 hours whether to cancel the order or wait for the item to be back in stock. 

    We reserve the right to cancel & refund any order where we cannot economically ship to. If this happens you will be refunded in full and notified of the issue. 


    Refund Policy


    Our policy lasts 30 days. If 30 days have gone by since your purchase, unfortunately we can’t offer you a refund or exchange.

    To be eligible for a return, your item must be unused and in the same condition that you received it. 

    To complete your return, we require a receipt or proof of purchase.

    Once your return is received and inspected, we will send you an email to notify you that we have received your returned item. We will also notify you of the approval or rejection of your refund.

    If you are approved, then your refund will be processed, and a credit will automatically be applied to your credit card or original method of payment, within a certain amount of days.

    Late Refunds
    If you haven’t received a refund yet, first check your bank account again.
    Then contact your credit card company, it may take some time before your refund is officially posted.
    Next contact your bank. There is often some processing time before a refund is posted.
    If you’ve done all of this and you still have not received your refund yet, please contact us at

    We only replace items if they are defective or damaged. If you need to exchange it for the same item, send us an email at and send your item to: 725 Evans Court, Kelowna, British Columbia, CA, V1X 6G4.

    To return your product, you should mail your product to: 725 Evans Court Kelowna British Columbia CA V1X 6G4

    You will be responsible for paying for your own shipping costs for returning your item. Shipping costs are non-refundable. If you receive a refund, the original cost of shipping will be deducted from your refund, unless you the customer paid the original shipping.

    Depending on where you live, the time it may take for your exchanged product to reach you, may vary.

    If you are shipping an item over $75, you should consider using a trackable shipping service or purchasing shipping insurance. We don’t guarantee that we will receive your returned item.



    Ask a Question
    • I see some sites saying you should add your calcium 15 minutes first to your res or the calcium will say in suspension & not mix with the other chemicals. What are your thoughts on this as it is put in after micro, grow & bloom

      Hi Brewster,


      It depends on the nutrients and how they react to calcium. For our nutrients we recommend mixing the micro, grow and bloom (micro first) and then adding the calcium. We've tested our nutrients, and based on our results you want to mix them in descending order (top to bottom) in accordance with our feed schedule ( Otherwise you risk them not reacting in the ideal manner.


      Thanks for reaching out and have a great day!

    • How much Ppms should 200ml in a 100liter Rez add ? It feels like it goes up a lot for the Amount used of the product.

      Hello. Thanks for reaching out to us.
      By itself Calnesium will raise ppm by 320 at 2ml/l. 
      Keep in mind that mixing it with other fertilizers will
      have a significant impact on this number since the
      other salts can increase or decrease the conductivity of the solution.

      Best regards


    • Hi There, why are you not able to use calnesium in the transplant stage?

      Hey Olivia, technically you could use Calnesium during the transplant stage, your plants would be fine.
      However if your plant is quite young we would recommend taking caution in adding too much ppm with the Calnesium.

      We just recommend it during early flower as that is when it will require it the most.

      Best regards

    • So wen I mix I only use 2 ml per litre right doesn’t seem like it’s a lot so I was just wondering

      Hey Jordy, hope you are having a good day.
      Our current calculator is recommending 1.5ml of Calnesium per 4L of water while your plant is in Veg growth.
      Once you flip your plants you could then bump the dosage of Calnesium to 2.5ml per 4L for the first 2 weeks of flower, followed by 5ml per 4L of water at week 3 of flower.
      ( please note this is for soil / coco, not Hydro feeding dosages )
      As the plant flowers it will want more Cal Mag and that is when Calnesium truly shines. Prior to that it is an essential nutrient recommended through out its life cycle.
      If you have anymore questions please let me now.

    • The label says " WARNING: Never combine the nutrients full strength. This can cause lock up. What does that mean? Do I lower my nutrient strength to 1/2 and use calnesium full strength?, or dont use calnesium at full strength? This is very confusing, I bought it on the recomendation of the shop keeper. I went there for calmag, he said this was better.

      Hello! What we mean by not mixing the nutrients full strength, you should always have a resivour with water to mix the nutrients. You don't want to mix the nutrients and addivties together in a small cup(without water) then pour it into the resivour.

      If you are confused on our feeding dosages please look to our nutrient calculator on our website.

      Going 1/4 strength is great for foliar spraying only or bare miminum feeding.
      Every feed/dosage should follow our calculator for best results.
      This is the same for calnesium 

      If you have anymore questions please feel free to message me on here or give us a call at 
      1 250 491 0255

      Thanks happy growing