Micronutrients + Biostimulants

Biostimulants and bloom boosters fine-tune a base feed with phosphorus and potassium in flower, trace minerals and root-zone biology. Pick a PK booster for peak flower, a micro or Epsom salt for deficiencies, or kelp, humic and microbes to support the roots.

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Micronutrients + Biostimulants

Biostimulants, Bloom Boosters and Micronutrients

Biostimulants, PK boosters and micronutrient supplements sit on top of a base feed to target flowering, uptake and root-zone biology. This collection covers CANNA PK 13/14, GH Liquid KoolBloom, Advanced Nutrients Big Bud and Aptus BloomBoost. GH FloraMicro, Epsom salts, kelp, humic acid, microbes and enzymes round it out....

Biostimulants infographic: PK boosters, micronutrients, kelp, humic acid, microbes and enzymes, NPK and timing

For complete liquid feeds and more bloom additives, see our liquid nutrients. Rooting products have their own root stimulators page, and both sit in the wider nutrients range.

Types of Flowering and Specialty Additives

Bloom and PK Boosters

Green House Feeding Booster PK+ is a 0-30-27 powder for stock tanks, and Cyco XL is a 0-40-0 from super phosphoric acid. GH Liquid KoolBloom runs 0-10-10 from early to late bloom. RAW Potassium is a 0-0-50 potassium sulfate for single-element corrections.

Micronutrients and Secondary Minerals

GH FloraMicro is a 5-0-1 with 5% calcium and chelated copper, iron, manganese and zinc. X Nutrients Micro runs all cycle at 15 mL per gallon. Monterey Epsom Salts supply 9.8% magnesium and 12.9% sulfur, and AmeriCal calcium nitrate adds 18% calcium.

Biostimulants and Microbes

FoxFarm Kelp Me Kelp You and Primordial Sea Green bring seaweed, and BioAg TM-7 pairs humic acid with seven micronutrients. Plant Success King Crab carries 11 bacteria species at 275 million CFU per mL. Hygrozyme 5X runs 5,000 U/mL cellulase to break down dead root material.

How Growers Use These Additives

Add concentrates one at a time to water, never to each other, and check pH and EC after mixing. Put acid additives like Cyco XL into plain water first. A PK booster adds to the total EC, so leave room for it in the base feed. Follow each label for rate and timing, since many boosters target only part of flower.

Frequently Asked Questions

What are biostimulants?

They are inputs that work on plant processes or root-zone biology instead of supplying main nutrients. Seaweed, humic acid, amino acids, microbes and enzymes all fit. Hygrozyme carries no NPK at all, because enzymes are not plant nutrients, and King Crab's active ingredients are 11 bacteria species.

When should you add a PK booster?

Most are timed to flower, not veg. General Hydroponics runs Liquid KoolBloom from early to late bloom, then switches to Ripen to finish. Advanced Nutrients aims Big Bud at the late flowering stages. Check each label, since the window and rate differ from one booster to the next.

Why does FloraMicro go in first?

FloraMicro carries 5% calcium. Mixed undiluted with FloraGro or FloraBloom, that calcium meets sulfate and phosphate and drops out as a white sludge plants cannot use. Add FloraMicro to plain water, stir, then add the other bottles, as General Hydroponics directs.