HP - high porosity

With its high perlite content, PRO-MIX HP provides a great growing environment to growers looking for a significant drainage capacity, increased air porosity and lower water retention. The added benefit of fibrous peat moss and coarse perlite makes this formulation ideal for growers who require a superior-quality product adapted to their needs for watering flexibility and crop seasonality.

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Questions to our experts


  • Annuals
  • Foliage plants
  • Potted flowering plants
  • Greenhouse vegetables
  • Young plant propagation
  • Vegetable transplants
  • Medicinal Plants
  • Berries


  • Dries out more frequently than general purpose, peat‑based mixes
  • Well suited for low-light growing conditions and high humidity
  • More difficult to overwater crops
  • Reduces incidence of water related problems (root diseases, algae and fungus gnats)
  • Holds less water for improved leaching of fertilizer salts during crop cycle


  • Premier Tech’s peat moss comes from bogs that are certified under the Veriflora Program. This certification ensures the application of good management principles in all aspects of sustainable development. The criteria include environmental assessment, social engagement, and product quality.

Active Ingredients


  • Improves fertilizer uptake; reduces fertilizer costs
  • Increases the resistance of plant to stresses; reduces maintenance costs
  • Optimizes results without changing growing practices
  • Increased root mass, flower production, plant size, yield
  • Improved water uptake and increased drought resistance

Advice from our specialist

How do I use PRO-MIX HP?

To use PRO-MIX HP, open the package, remove some PRO-MIX product and place into a large tub or container. Lightly break up any clumps so that the PRO-MIX is light and airy. Most growers prefer to add a small amount of water prior to filling containers. If you add water, add enough so that the PRO-MIX product is slightly moist to touch. Do not saturate. 

Fill flats, containers and/or pots, without compacting the PRO-MIX in the container.  Plant your seedlings, young plants, etc., then water in containers.

What's the difference between PRO-MIX BX and HP?

PRO-MIX BX is a general purpose growing medium, compared to PRO-MIX HP which is a High Porosity growing medium. These products are the same in pH and chemical properties.  The difference is that PRO-MIX HP contains a higher percent of perlite than PRO-MIX BX. Perlite is a porous aggregate that does not absorb water.

When incorporated into growing media, perlite provides air porosity and reduces water retention. Since PRO-MIX HP contains a higher percentage of perlite than PRO-MIX BX, HP holds less water and is better suited for crops that are sensitive to over watering, to low light growing conditions or for use in winter months when daylight is shorter.

What is the pH of PRO-MIX HP?

Using the Saturated Media Extraction test method (SME), PRO-MIX HP is formulated in a pH range of 5.2-6.2. Once product is opened, crops planted and watered, limestone is activated and pH will reach 5.8-6.2 within 7-10 days.  

Can you reuse PRO-MIX HP?

We do not recommend to re-use PRO-MIX HP or any growing medium. There are many good reasons to not recycle, among these include changes to chemical and physical properties over time when in use, diminished effect of wetting agent after use and/or transmission of root diseases to newly planted crops.

When to water PRO-MIX HP?

When irrigating, add water to PRO-MIX HP until it is saturated from top to bottom of the container. You will know you have accomplished this when water runs out of the drainage holes at the bottom of the container. Over time, allow the growing medium to dry-out without applying additional water.

You will know when to apply water again when the surface of the growing medium turns color from a dark brown/black (wet) to a light brown/tan color (dry enough to rewater). 

Does PRO-MIX HP have nutrients?

Yes, PRO-MIX contains a starter fertilizer to help plants acclimate to a new rooting environment. We strongly recommended to initiate a fertilizer program within 7-10 days after planting. The fertilizer program you select should take into consideration water quality, crop type and the stage of plant growth.

Is PRO-MIX HP good for seedlings?

PRO-MIX HP can be used for transplanting seedlings. However, we suggest PRO-MIX FPX BIO-FUNGICIDE for seed starting and seed germination.

Is PRO-MIX HP soilless?

PRO-MIX HP is a peat-based growing medium formualted with a high percentage of perlite. PRO-MIX HP and all PRO-MIX growing media products are 'soilless', meaning that they do not contain any mineral soil. 

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Training center


  • SPHAGNUM PEAT MOSS (65-75%) ?

    Canadian Sphagnum peat moss is a natural, organic matter that comes from a peat bog. This primary resource is carefully harvested by vacuum harvesters. Peat moss comes in various fibrosity and levels of decomposition. Once carefully graded, peat moss assures that qualities of each grade are optimized for based on grower and uses for a final product reaching high quality requirements.


    Perlite is an alumino-silicate ore of volcanic origin. The raw ore is crushed, graded and screened in various particle sizes. Perlite has a high total-porosity and improves drainage and air porosity.


    Used to adjust pH to optimum range. Also a source of Calcium and Magnesium.


    A wetting agent is a substance that reduces the surface tension of water, allowing water to penetrate and uniformly wet growing media.


    PTB297 Technology, Glomus intraradices - Mycorrhizae are beneficial associations between a mycorrhizal fungus and roots, creating a network of filaments that explores the soil and access more nutrients and water, and transfer them to the plant.

Documents and specifications

Code Size (Regional availability may vary) Units per pallet Weight
20221RG 2.2 cu ft Loose * 30 lb
* Sold at Lowes and Home Depot
20281RG 2.8 cu ft Loose 57 25 - 35 lb
20381RG 3.8 cu ft Comp. 30 60 - 75 lb
20551RG 55 cu ft Comp.*** 2 800 - 1050 lb
***West only
20801RG 80 cu ft Loose 2 700 - 850 lb
21351RG 135 cu ft Comp. 1 2200 - 2700 lb
Size (Regional availability may vary) 2.2 cu ft Loose *
Units per pallet
Weight 30 lb
Size (Regional availability may vary) * Sold at Lowes and Home Depot
Units per pallet
Size (Regional availability may vary) 2.8 cu ft Loose
Units per pallet 57
Weight 25 - 35 lb
Size (Regional availability may vary) 3.8 cu ft Comp.
Units per pallet 30
Weight 60 - 75 lb
Size (Regional availability may vary) 55 cu ft Comp.***
Units per pallet 2
Weight 800 - 1050 lb
Size (Regional availability may vary) ***West only
Units per pallet
Size (Regional availability may vary) 80 cu ft Loose
Units per pallet 2
Weight 700 - 850 lb
Size (Regional availability may vary) 135 cu ft Comp.
Units per pallet 1
Weight 2200 - 2700 lb

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