PRO-MIX HP Growing Medium with Mycorrhizae, 3.8 cu ft

High-Porosity Medium for Water-Sensitive Crops, 3.8cu ft Package

Water-sensitive crops, freshly rooted cuttings, and plants grown under low-light conditions all share the same risk: a medium that holds too much water for too long. PRO-MIX HP Mycorrhizae is a high-porosity, peat-based medium built on 65-75% Canadian sphagnum peat moss with horticultural grade perlite, dolomitic and calcitic limestone, and a wetting agent, with Mycorrhizae (Glomus intraradices) blended in for root development.

This 3.8cu ft package offers more usable volume per purchase than the 2.8cu ft size, suited to larger propagation or water-sensitive-crop programs.

Key Features & Benefits

• High Air Capacity and Drainage — the elevated perlite content is formulated for water-sensitive crops that don't tolerate a saturated root zone.
• Mycorrhizae (Glomus intraradices) — a beneficial endomycorrhizal inoculum that supports nutrient and water uptake at the root.
• 65-75% Canadian Sphagnum Peat Moss — the fibrous base of the medium, balanced against the elevated perlite content.
• Dolomitic & Calcitic Limestone — pre-adjusts substrate pH before the bag or bale is opened.
• Integrated Wetting Agent — helps the medium re-wet evenly instead of forming dry, hydrophobic pockets.

Who Should Use PRO-MIX HP Mycorrhizae

This medium fits growers working with water-sensitive crops, rooting cuttings, or low-light growing conditions who need higher air capacity and drainage than a general purpose medium provides.

About PRO-MIX

Premier Tech has sold peat substrate since 1923 and has marketed PRO-MIX as its growing-media brand since 1968. Its biotechnology lab produces the Glomus intraradices mycorrhizal inoculant blended into the HP line.

Frequently Asked Questions

What is this medium ideal for?

It's formulated for water-sensitive crops, rooting cuttings, and low-light growing conditions, where a saturated root zone is a bigger risk than it would be for a standard transplant crop. Growers doing general greenhouse transplanting without those concerns may prefer PRO-MIX BX instead.

What is the peat content?

The mix runs approximately 65-75% Canadian sphagnum peat moss by volume. That's a lower percentage than PRO-MIX BX's 75-85% range, with the difference made up by additional perlite for drainage.

What does the Mycorrhizae add?

Mycorrhizae (Glomus intraradices) is a beneficial endomycorrhizal inoculum blended into the medium to support nutrient and water uptake at the root. No separate inoculation step is needed.

Why does this medium include limestone and a wetting agent?

Dolomitic and calcitic limestone pre-adjust the substrate's pH before the bag is even opened. The integrated wetting agent then helps the medium re-wet evenly instead of forming dry pockets after it dries down between waterings.

How many package sizes are available?

This HP formula ships in both 2.8cu ft and 3.8cu ft formats. Choose the size that matches a single propagation bench or a larger commercial program.