PRO-MIX® HP® Biostimulant Open Top Grow Bags - Enhanced Plant Growth


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PRO-MIX® HP Open Top Grow Bag

Introducing the PRO-MIX HP open top grow bag, the perfect solution for cultivators of all plant types. Available in two convenient sizes (3.5 gal/14.2L or 7gal/28.3l), this loose-fill growing medium comes equipped with eight pre-made drip holes and a convenient tear-off opening for effortless use.

Featuring multiple openings, the open top design provides superior aeration in the root zone, ensuring equal air distribution and promoting healthy root development. With the inclusion of mycorrhizae, this growing medium not only improves root growth, but also enhances water and nutrient uptake while increasing plant resistance to environmental stresses such as drought, compaction, salinity, low fertility, and transplant shock. Upgrade your growing game with the PRO-MIX HP open top grow bag.


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  • Time and cost savings: The PRO-MIX® HP® Biostimulant Open Top Grow Bags require less labor, quick setup, and easy handling. With no container required and a tear-off opening, the grow bags offer a cost-effective solution for plant cultivation.
  • Cleaner: The open top grow bags decrease the risk of handling contamination and eliminate the need for cleaning or sterilization, providing a cleaner environment for plant growth.
  • Adapted: The same PRO-MIX® HP® formula is used in the open top grow bags, providing good drainage capacity, high air porosity, and lower water retention. This makes it easier for roots to breathe and helps to promote healthy root development.
  • Ready-to-use bag: The grow bags come with eight pre-made drainage holes and a unique design that promotes root development, allowing for improved leaching of fertilizer salts during the crop cycle. The ready-to-use bags eliminate the need for any additional setup, saving you time and effort.

Cronk Nutrients #1 Recommended Peat-Based Growing Medium:

Pro-Mix HP is a premium, high-porosity growing medium that is compatible with a variety of plant types and growing systems. Whether you're growing in containers or raised beds, using drip irrigation or hand watering, Pro-Mix HP is the ideal choice for healthy plant growth and development. pH-adjusted for optimum growing conditions, Pro-Mix HP is also compatible with all Cronk Nutrients, ensuring consistent and reliable results with every use.


  • Canadian sphagnum peat moss (65-75%)
  • Perlite - horticultural grade
  • Dolomitic and calcitic limestone (pH adjuster)
  • Wetting agent

Active Ingredients:

  • Bacillus - PTB180 Technology, Bacillus pumilus
  • Mycorrhizae - PTB297 Technology, Glomus intraradices

Bacillus stimulates root hair proliferation for better nutrient absorption and faster growth. Mycorrhizae expand root growth, enhance nutrient uptake, and reduce transplant shock. Canadian sphagnum peat moss and perlite improve air porosity and drainage, while dolomitic and calcitic limestone adjusts pH and provides calcium and magnesium.

Pro-Mix HP Mycorrhizae Open Top Grow Bag Video



  • Less labor
  • Quick set-up
  • Easy to handle
  • No container required


  • Decreased risk of handling contamination
  • No cleaning or sterilization needed
  • Cleaner environment


  • Unique design which increases root development
  • Improved leaching of fertilizer salts

Bringing PRO-MIX® HP® in a fully adapted solution for your grow tent

PRO-MIX® HP Open-Top Grow Bag
Bullet image 1 PRO-MIX® HP® provides a great growing environment to growers looking for a significant drainage capacity, increased air porosity, and lower water retention.
Bullet image 2 Includes 8 precut drainage holes to avoid overwatering plants.
Bullet image 3 With its light color and breathable material, the bag itself is designed to promote root growth and expansion.
PRO-MIX® HP Open-Top Grow Bag



Shake the bag to gently unpack the growing medium


Tear the removable part of the bag


Transplant directly in the bag, avoiding compaction

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