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Grow Gear


MassBoost is an organo-mineral plant booster that prevents Calcium (Ca) and Magnesium (Mg) deficiencies while stimulating powerful fruit set and development.

Calcium and magnesium are very active molecularly and are easily locked up or combined with other minerals in the growing medium. Both minerals are extremely important for floral and fruit set and development. MassBoost provides both minerals in a highly bioavailable form by chelating in L-amino acids. The L-amino acids also help to minimize antagonism with other minerals in the growing medium.

MassBoost is effective when applied to the roots in a feed solution. It is also very effective as a foliar treatment either as maintenance or to treat deficiencies. The L-amino acids help make the minerals easily absorbed into the leaf tissue.


Why Use MassBoost

  • Provides organic Nitrogen combined with Calcium and Magnesium and L-Amino Acids that stimulate plant development
  • 100% water soluble and leaves no residue
  • Combines Calcium (Ca) and Magnesium (Mg) with L-Amino Acids to eliminate deficiencies
  • High bioavailability
  • Improves structure and firmness of the flower and fruit
  • Provides the extra boost plants need during certain plant development phases


How to Use MassBoost

MassBoost should be used during all stages of plant development, with increased dosage through the flowering phase. If needed MassBoost should be used at a lower dosage or as a foliar spray.

When using reverse osmosis (RO) water and soilless mediums (like coco coir), higher dosages of MassBoost may be needed.

When mixing with any phosphorus supplements (like PeakBoost), be sure to allow one to mix in the solution before adding the other to minimize the formation of calcium-phosphate bonds, which renders both unavailable to the plant.

Foliar feeding note: For best results mix FaSilitor in the foliar mix first, then add MassBoost and adjust pH to about 5.8. The L-amino acids in MassBoost act as a surfactant. Together this foliar treatment works to prevent and fix many nutritional imbalances.

*Take care when using MassBoost on young plants because the nitrates (along with other nitrates from your base fertilizer) can cause tip burn and stress. If this is the case use a CaMg supplement without nitrates to buffer RO water.

Customize your feeding schedule with the Aptus Nutrient Calculator



  • Organic Nitrogen provided by L-amino acids promotes robust vegetative growth and photosynthesis without risk of burning or overdose. Read more on L-amino acids under Core Product Technologies.
  • Full spectrum organic L-amino acids provide growth materials, plant and microbe bio-stimulation, and boost beneficial bacteria populations.
  • Both minerals are important to photosynthesis, especially when combined with L-amino acids
  • Calcium is deposited in cell walls to improve structure, dry weight, and firmness of fruits and flowers
  • Calcium is responsible for fruit set and floral development. Many fruiting and flowering crops drop their blossoms when calcium is deficient or unavailable.
  • Calcium activates various enzymatic activities which are precursors to many other plant processes
  • Higher levels of Ca and Mg help raise internal plant pH to resist fungal attacks


MassBoost Key Ingredients

  • L-amino acids, which provide organic nitrogen (N)
  • Calcium (Ca)
  • Magnesium (Mg)


Tips from the field

  • Use MassBoost in combination with PeakBoost & FinaleBoost in the last weeks to get maximum weight, firmness, and quality.
  • Pay attention when you mix PeakBoost and MassBoost as they can react together. Always add one, dilute and mix then the other. In case you use a lot of Phosphorus based products, then take care when adding MassBoost as Phosphorus and Calcium mixed together in high concentrations may cause deposits and residues.
  • MassBoost contains low levels of nitrates that can sometimes cause tip burn if fed at too high of rates on young or weak plants. If you use MassBoost during early growth, start with a lower dosage and work up to full dosage based on your plant's response.




Nitrate Nitrogen (K03) Calcium Nitrate

Magnesium Nitrate 5%

Calcium (Ca) Calcium Nitrate 7%

Magnesium (Mg) Magnesium Nitrate 1%

Returns Policy

You may return most new, unopened items within 30 days of delivery for a full refund. We'll also pay the return shipping costs if the return is a result of our error (you received an incorrect or defective item, etc.).

You should expect to receive your refund within four weeks of giving your package to the return shipper, however, in many cases you will receive a refund more quickly. This time period includes the transit time for us to receive your return from the shipper (5 to 10 business days), the time it takes us to process your return once we receive it (3 to 5 business days), and the time it takes your bank to process our refund request (5 to 10 business days).

If you need to return an item, simply login to your account, view the order using the 'Complete Orders' link under the My Account menu and click the Return Item(s) button. We'll notify you via e-mail of your refund once we've received and processed the returned item.


We can ship to virtually any address in the world. Note that there are restrictions on some products, and some products cannot be shipped to international destinations.

When you place an order, we will estimate shipping and delivery dates for you based on the availability of your items and the shipping options you choose. Depending on the shipping provider you choose, shipping date estimates may appear on the shipping quotes page.

Please also note that the shipping rates for many items we sell are weight-based. The weight of any such item can be found on its detail page. To reflect the policies of the shipping companies we use, all weights will be rounded up to the next full pound.

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