Grotek Monster Bloom - High-PK Bloom Booster for Bigger Flowers
Best for: growers on any base feed who want a straightforward PK boost to pack on flower size and density through bloom.
Our thoughts
Monster Bloom is one of Grotek's longest-running products and it's stuck around because it's simple - a concentrated PK powder you add on top of your existing feed, nothing more complicated than that. If you want a reliable way to fatten up buds without learning a new feed chart, this does the job without any fuss.
Monster Bloom is a water-soluble powder bloom booster from Grotek with an NPK ratio of 0-50-30, making it one of the more concentrated PK additives on the market. It's designed to be added during the flowering stage to support the transition from floral initiation through to full bud development, supplying the extra phosphorus and potassium that plants draw on heavily once they start flowering.
Because it's a powder rather than a liquid, a little goes a long way - it dissolves into your existing nutrient solution rather than replacing any part of your base feed. Grotek recommends starting once buds begin forming and continuing with every feed through the bloom cycle, then stopping 1-2 weeks before harvest.
How it compares
Monster Bloom sits alongside the established names in PK bloom boosters.
- Compared with Canna PK 13/14, which is a liquid dosed in the last weeks of flower, Monster Bloom is a powder concentrate used across the whole bloom cycle rather than just the finishing stretch.
- Compared with Advanced Nutrients Big Bud, which is a lower-strength liquid, Monster Bloom's 0-50-30 ratio means you're dosing a much more concentrated product, so small amounts go further.
- Compared with House & Garden Bud-XL, another liquid PK additive, Monster Bloom's powder format tends to work out cheaper per litre of feed once mixed.
It won't replace a full bloom base feed, but as a PK top-up it's a concentrated, budget-friendly way to bulk out flower size.
Usage guidance
Simple to fold into an existing feed schedule.
Dosing
Mix a small measure of powder (check the rate on the pack for your reservoir size) into your nutrient solution alongside your regular base feed, once buds have started forming.
Timing
Use with every feed through the bloom cycle, then stop 1-2 weeks before harvest to let the plant finish naturally.
Compatibility
Don't run it alongside other PK-boosting additives at the same time - stacking high-PK products can tip plants into nutrient burn rather than improving results.
Technical specifications
- NPK ratio: 0-50-30
- Format: water-soluble powder concentrate
- Brand: Grotek
- Use period: floral initiation through to late flower, stop 1-2 weeks pre-harvest
- Compatible media: hydroponics, coco, soil
- Pack sizes: available in a range of sizes from small retail tubs up to bulk
- Storage: keep sealed, dry, out of direct sunlight
Who this is for
- Growers running any base nutrient line who want extra bud density without changing their whole feed
- Budget-conscious growers who want a concentrated powder rather than paying for a lot of bottled water in a liquid booster
- Hydro, coco and soil growers, since it works across all three
- Anyone who already knows and trusts Grotek's range
Our take
Monster Bloom does one job - putting extra phosphorus and potassium into your feed during bloom - and it does it at a concentration that means you're not paying to ship bottles of water around. It's a sensible top-up rather than a replacement for your main bloom nutrient.
Does exactly what it should, day in, day out - worth picking up if you want a proven PK booster without overcomplicating your feed schedule.
