BioBizz Top-Max - Organic Bloom Stimulator for Bigger, Denser Flowers
Best for: growers wanting an organic alternative to mineral PK boosters during the flowering stage.
Our thoughts
Top-Max isn't a feed in the normal sense, it's a stimulant, and the numbers on the bottle reflect that: tiny NPK values because that's not the job it's doing. It works alongside your normal bloom feed rather than instead of it, and it's a solid organic option if you don't want mineral PK boosters anywhere near your flowers.
Top-Max is BioBizz's 100% vegetable-based, certified organic bloom stimulator. Rather than delivering a strong NPK hit, it works through fulvic acids and a smaller amount of humic acid, both derived from natural leonardite, which is why the NPK figures on the label are deliberately low. Its role is to encourage cell division and improve the transport of nutrients, sugars and trace elements to the developing fruit and flowers, which in turn raises Brix (sugar) levels and supports the natural oils, flavours and aromas that develop during flowering.
It's mainly used in the flowering stage for soil-grown plants, dosed at 2 to 5ml per litre of water with every watering through the flowering cycle. BioBizz suggest pairing it with Bio-Bloom, and their Bio-Heaven additive, as an organic alternative to synthetic mineral PK boosters.
How it compares
Top-Max sits in the bloom-stimulator category alongside both organic and mineral competitors.
- Vs mineral PK boosters like Advanced Nutrients' bloom-stage additives: mineral boosters deliver a direct, measurable phosphorus and potassium spike, while Top-Max works indirectly through fulvic and humic acid to improve nutrient transport, a different mechanism aimed at the same end result.
- Vs Canna's PK 13/14: PK 13/14 is a concentrated mineral PK booster with an exact, high NPK figure, useful for growers who want precise control, but it isn't organic.
- Vs BioBizz's own Bio-Bloom: Bio-Bloom is the base bloom feed, Top-Max is the additive layered on top of it, not a replacement.
You're trading the precision of a mineral PK number for a genuinely organic, leonardite-based stimulant that works on the plant's own nutrient uptake rather than force-feeding phosphorus and potassium.
Usage guidance
Straightforward dosing on top of your existing bloom feed.
Dosage
Use 2 to 5ml of Top-Max per litre of water, mixed in with every watering through the flowering cycle.
Pairing
Run it alongside Bio-Bloom as your base bloom feed, and consider adding Bio-Heaven for a fuller organic PK-boost combination.
Soil grows
Top-Max is mainly formulated for soil-grown plants, so it's best suited to soil and soil-enriched coco setups rather than pure hydro systems.
Technical specifications
- Base ingredients: fulvic acid and humic acid from natural leonardite
- NPK ratio: very low (stimulant, not a base feed)
- Certification: 100% organic, vegetable-based
- Growth stage: flowering
- Dosage: 2-5ml per litre of water
- Best suited to: soil and soil-enriched coco
- Sizes available: 500ml, 1L, 5L, 10L
- Vendor: BioBizz (Netherlands)
Who this is for
- Organic soil growers wanting an alternative to mineral PK boosters
- Growers running the full BioBizz range through flowering
- Anyone chasing better flavour, aroma and resin development rather than just yield
- Growers who prefer working with the plant's own nutrient transport rather than a direct PK spike
Best suited to soil grows in flowering where you want to boost quality without introducing mineral boosters.
Our take
Top-Max does a genuinely different job to a mineral PK booster, and if organic certification matters to your grow, it's one of the more established ways to get a similar end result in bud density and quality.
Worth picking up if you're already running Bio-Bloom and want to push flower quality a bit further.
