Grow More® Mendocino Producer's Choice Flower Hardener 00-37-37 — 25 lb

Zero-Nitrogen Finishing Powder Built for Maximum Flower Density in the Final Weeks

Carrying nitrogen too far into the last stretch of flowering keeps signaling vegetative growth right when a crop should be maturing and hardening off instead. Grow More Mendocino Producer's Choice Flower Hardener 00-37-37 removes nitrogen entirely and delivers equal, high-concentration phosphate and potassium at 37% each, an extreme profile designed exclusively for the final stage of the crop cycle so plants direct all available energy toward flower maturation and structural hardening.

As the most focused finishing tool in the Mendocino Producer's Choice lineup, the 25 lb bag dissolves completely with no residue and is introduced during the final two to four weeks before harvest.

Key Features & Benefits

• Zero Nitrogen for Pure Finishing Conditions: Eliminating nitrogen entirely removes vegetative drive and focuses the plant on completing reproductive development.
• 37% Phosphate for Sustained Late-Stage Energy: High phosphate continues powering ATP synthesis and metabolic function during the final flowering and maturation phase.
• 37% Potassium for Structural Hardening: Equal high potassium activates key enzymes, drives carbohydrate synthesis, and thickens cell walls.
• Balanced 0:1:1 P:K Finishing Ratio: Purpose-built for late-stage finishing where both energy and structure are critical without nitrogen interference.
• 100% Water-Soluble: Dissolves completely with no insoluble residue, protecting irrigation equipment and enabling precise dosing.

Who Should Use This

Advanced indoor cultivators and commercial greenhouse operators who use stage-specific nitrogen-withdrawal strategies in the final phase of the crop cycle are the direct fit, particularly growers focused on maximizing flower density and structural quality before harvest.

About Grow More Inc.

Grow More Inc., founded in 1918 as National Chemical Company in Hollywood, California and now based in Gardena, California, positions Flower Hardener as the zero-nitrogen finishing formula in its Mendocino Producer's Choice powdered line.

Frequently Asked Questions

Why is a zero-nitrogen formula beneficial in late flower?

During the final stage of flowering, nitrogen drives new vegetative growth and can delay maturation. Withdrawing nitrogen while maintaining high P and K keeps metabolic energy focused on flower compaction, carbohydrate accumulation, and completing reproductive development.

When should I transition from my bloom formula to the Flower Hardener?

Most growers transition to a zero-nitrogen or near-zero-nitrogen formula during the final 2 to 4 weeks before harvest, depending on crop type and observed maturation speed. Monitor flower development as a guide for timing the transition.

Can I use this with a flushing agent at the end of the cycle?

Yes, many growers use the Flower Hardener through the penultimate stage of the crop cycle, then follow with a dedicated flush solution in the final days before harvest to clear accumulated salt deposits from the root zone. This two-step approach — Flower Hardener through the penultimate stage, then a dedicated flush — is a common way growers finish a crop cleanly.

Is this formula compatible with drip and recirculating hydroponic systems?

Yes, the 100% water-soluble powder is compatible with drip, DWC, NFT, and flood-and-drain systems. Continue calcium-magnesium supplementation throughout the finishing stage alongside it.