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PRO-MIX® FPX and PGX – Improved products for young plant propagation in paper-wrapped pots

Over the last several years there has been an increasing trend for “Young Plant” producers to move from seed germination to cutting propagation. This has become popular for the many specialty varieties and branded plants. While young plants are still produced with seed germination and plugs systems, the propagated and rooted cutting market has evolved into new processes with specialized equipment. One of the more popular methods for cutting production is the use of paper-wrapped pots.

Paper-wrapped pots are available in assorted diameters, ranging from 15 mm up 120 mm (5/8” – 4.75”). Growing media is fed into the machine as paper is wrapped around the growing media to form a continuous, extruded tube that is cut into a specific length to form paper pots that are placed into individual cells with a growing tray. The smaller size paper-wrapped pots (15-35 mm) are used mostly for cutting propagation. Larger sizes are used for propagation of greenhouse foliage, woody ornamentals for nursery and ready-plant annuals for the landscape trade. There are different needs for growing medium for each of these applications.

rosemary cuttings

"Rosemary cuttings rooted in 25mm paper-wrapped cells."

Premier Tech Horticulture has made slight modifications to its line of growing media for small cell applications. Our two popular blends, PRO-MIX® FPX and PRO-MIX® PGX, have been improved for cutting propagation as well as for seed germination in small cell culture. What are these improvements?

First, there has been the installation of new ‘state of the art’ screening equipment at our factories to remove small roots (sticks) from Sphagnum peat moss. This new screening equipment allows the use of more fibrous peat for PRO-MIX® FPX and PGX for better physical structure of the growing medium, without the roots (sticks) or debris. Cleaner product works better with automated machinery and less worries of bridging of small cells with plug trays.

Second, PRO-MIX® FPX and PGX are now formulated with a lower rate of calcitic limestone than in the past. This means less concern of media pH climb due to water alkalinity, which can be problematic for propagated cuttings and seed germination trays in the initial rooting stage.

PRO-MIX® FPX and PGX are available as standard blends or with BIOFUNGICIDE™ (not available in Canada) for added protection from plant root pathogens, such as Fusarium, Pythium and Rhizoctonia.



Both these PRO-MIX® products are designed for the germination of various seeds. Understanding the performance differences is important to be sure your customers use the best product for their particular application(s). 

Major Components:


  • 85% Fine Canadian Sphagnum Peat Moss
  • 15% Fine Perlite


  • 78% Fine Canadian Sphagnum Peat Moss
  • 22% Fine Vermiculite

Minor Components: Calcitic and dolomitic limestone, starter fertilizer charge and wetting agent are incorporated at the same rates in both products.


What are the differences?

Chemical Properties:      

  • The type of peat moss used is the same for both products.
  • The perlite component in PRO-MIX® FPX is inert and has no effect on chemical properties.
  • The vermiculite component in PRO-MIX® PGX has a slight capacity to retain nutrients (CEC - cation exchange capacity). Vermiculite also contains small amounts of potassium, magnesium and calcium. However, these differences are not significant under typical growing conditions.

Physical Properties:


  • PRO-MIX® FPX holds less water than PGX; therefore, it dries off faster. 
  • FPX requires more frequent irrigation/watering. Therefore, a grower who prefers a faster drying rate or has recurring water-related root diseases will prefer this formulation. 
  • FPX is also easier to leach if a grower has water with a high salt content.

PRO-MIX® PGX         

  • PRO-MIX® PGX holds more water than FPX; therefore, it dries off slower.
  • Watering frequency is reduced, which saves water and reduces labor.
  • Plugs can be pulled out and transplanted a few days earlier in PGX vs. peat-perlite mixes due to advanced rootball/plug formation. 
  • Compared to peat-perlite mixes, peat-vermiculite blends produce a better plug for transplanting since root mass stays intact when pulled out from trays. Many field transplant growers and farmers of vegetables and tobacco prefer this feature.


For more information, contact your Premier Tech Horticulture Grower Services Representative.

PRO-MIX® is a registered trademark of Premier Horticulture Ltd.

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