IBA Rooting Hormone (Liquid Concentrate) Storage & Tank Compatibility

Storing IBA Rooting Hormone (Liquid Concentrate)? Start Here

IBA rooting hormone is not a single chemical but a formulated plant-growth-regulator concentrate. The active is indole-3-butyric acid (IBA), an auxin that stimulates adventitious root formation on cuttings; many commercial blends pair it with naphthaleneacetic acid (NAA). Because the IBA acid form is only sparingly water-soluble (~250 mg/L), professional liquid concentrates dissolve it in an alcohol carrier (typically ~75% aqueous ethanol or isopropanol) at roughly 10,000–50,000 ppm; the alcohol also acts as a self-sanitizing agent. A second product class uses the potassium salt (K-IBA), which is fully water-soluble and dispensed as a dilute aqueous solution or spray. These are used across horticulture, nursery propagation, and tissue culture. Material of construction matters because the two forms behave differently: the alcohol concentrate is a flammable liquid that polyethylene resists chemically but that triggers flammable-liquid storage rules, while the water-soluble form is benign and poly-friendly.

Is Polyethylene (HDPE / XLPE) Safe for IBA Rooting Hormone?

Yes — polyethylene is chemically compatible (rating S). Both forms of the formulation fall inside the comfort zone of HDPE and crosslinked polyethylene. Published polyethylene resistance charts rate ethanol (to 95%) and isopropanol (to 100%) as excellent, and PE also resists the dilute organic acids and aqueous salt content of these blends. So neither the alcohol carrier nor the auxin actives chemically attack the resin.

The honest caveat is flammability, not chemistry: an alcohol-carried concentrate is a flammable liquid (representative NFPA F = 3). For those concentrates, follow flammable-liquid practice — bonding and grounding, vapor/ignition control, and the spacing and containment your local code requires; many facilities prefer grounded metal or vinyl-ester FRP for bulk flammable service even though poly resists the fluid. Water-soluble K-IBA dilutions are non-flammable and are routinely and safely stored in poly tanks. Confirm against the product-specific SDS, since carrier type and concentration vary by manufacturer.

Material compatibility at a glance

Polyethylene (HDPE/XLPE) is chemically compatible with both the water-soluble K-IBA dilutions and the alcohol-carried concentrates, because PE resists ethanol, isopropanol, dilute organic acids, and aqueous salt solutions. The governing design issue for the solvent concentrate is therefore not chemical attack but flammability: an ethanol/IPA carrier gives a flammable liquid that demands bonding, grounding, vapor control, and a Class I area approach. Water-soluble K-IBA in water is non-flammable and routinely stored in poly. Choose poly or PP for ambient handling; use grounded/bonded steel or vinyl-ester FRP where flammable-liquid codes apply.

Ratings: S suitable · C conditional / limited · U unsuitable. Verify against the cited resistance charts and your concentration/temperature before specifying.

The safety that actually matters

• Flammable carrier: alcohol-based concentrates emit flammable vapor (H226) — keep away from heat, sparks, and open flame; bond and ground transfer equipment.
• Toxic if swallowed (H301): the IBA active is acutely toxic by ingestion — never store in food/beverage containers; keep labeled.
• Irritant: causes skin (H315), eye (H319), and respiratory (H335) irritation — wear chemical goggles, gloves, and provide ventilation.
• Vapor control: use in well-ventilated areas; alcohol vapors can accumulate in closed spaces.
• Incompatibles: keep away from strong oxidizers and strong bases; store cool and out of direct sunlight.
• SDS first: hazard profile varies sharply between alcohol concentrates and water-soluble K-IBA — always verify the specific product SDS before tank selection.

Common questions

Can I store liquid IBA rooting hormone in an HDPE or poly tank?

Yes — polyethylene chemically resists both the alcohol carrier and the auxin actives, so the rating is compatible (S). For alcohol-based concentrates, the real requirement is flammable-liquid handling (bonding, grounding, vapor control), not a different tank resin; water-soluble K-IBA forms are non-flammable and routinely kept in poly.

Why is the liquid concentrate flammable if IBA itself is a solid?

IBA acid is barely water-soluble, so concentrates dissolve it in roughly 75% aqueous ethanol (or isopropanol) at 10,000–50,000 ppm. The alcohol carrier is the flammable component — it gives the product a low flash point even though the active ingredient is a benign crystalline solid.

Is the potassium-salt (K-IBA) version handled differently?

Yes. K-IBA is fully water-soluble and dispensed as a dilute aqueous solution, so it is non-flammable and only mildly hazardous. It is the easiest form to store in standard poly tanks; the alcohol concentrate is the one that triggers flammable-liquid precautions.

What is the pH and is it corrosive to steel?

The acid concentrate is mildly acidic (about pH 3.5 on a 1% basis), while K-IBA solutions run near-neutral to mildly alkaline — values are SDS-dependent. The dilute acidic fraction can slowly corrode bare carbon steel, so use poly, PP, 316 stainless, or vinyl-ester FRP for long-term storage.