Humboldt Nutrients and Bloom
Humboldt Nutrients makes a big range, from bases right through to inoculants. A fair few of their bottles sit near a Bloom one. Here’s how they line up, and the few jobs their list leaves open.
Last checked 5 November 2026 · Public information only
This Fit Report is a summary of publicly available information about Humboldt Nutrients and its products, taken from their own website, labels and published material as of 5 November 2026. We’ve linked each source so you can check it yourself. Rates are as printed on each company’s own pages; we don’t show prices. It isn’t affiliated with, endorsed by or approved by Humboldt Nutrients, and product names belong to their owners. Products, rates and claims change, so please confirm current details with the manufacturer before making any decision. Spotted something out of date? Email nathan@bloomyellowbottles.com and we’ll correct it.
A wide range, lots of near neighbours.
Humboldt’s 27-product shop covers bases, cal-mag, PK, silicon, humic acid, a rooting product and a carb additive. So most of this report is about pairs: two bottles for the same job, one from each range. What their list doesn’t carry is a by-stage additive set, a kelp or fish tonic you dose on its own, sea minerals or foliar sprays.
- Stays as is: Master A and B, the 3-part, Oneness, the soil-only naturals, Myco Madness, Prozyme and Sticky.
- Both have one: cal-mag, PK, silicon, humic, rooting and carbs. Pick one, or test them side by side.
- Not on their list: Pre, Ultra, Phat, Ooze and Final, kelp and tuna tonics, sea minerals and foliars.
Humboldt Nutrients and Bloom in short
Their bases (Master A and B, 3-part, Oneness, Naturals), Myco Madness, Prozyme and Sticky.
Calyx Magnum, Ginormous, Structural Integrity, Humboldt Roots, Hum-Bolt and Honey ES each sit near a Bloom bottle.
Bloom’s by-stage additives, Seaweed, Seafuel, Sea Minerals and the two foliar sprays.
Their line, Bloom’s fit at a glance
Matched on job, not NPK. Humboldt’s product pages print analysis but mostly not rates; Bloom prints ml per litre on a weekly feed chart. Tap a tag to filter.
Keep your base. Bloom’s additives go in on top of it.
A three-part base stays put. Bloom’s additives sit alongside it.
Nothing in Bloom’s range does this job, so it stays.
Their soil program stays. Bloom’s additives work in soil too.
Both are calcium and magnesium. Calyx lists nitrogen and iron; Bloom’s lists iron and zinc. Pick one.
All three are PK. Bloom’s PK is an as-needed bottle at peak bloom. Plan the stack, or pick one.
Both put silicon in the tank. One is plenty, so pick one or test them.
Same name, same early job. Bloom’s Roots carries amino acids, B vitamins and fulvic acid.
All humic acid products. Run one through the cycle, or test them.
Both put carbohydrates in. Honey ES adds seaweed; SWTNR adds potassium.
Bloom has no inoculant, enzyme or wetting agent, so these stay.
Southern bull kelp, a tuna and kelp tonic, and trace minerals from sea water.
One bottle for each stage, from mid veg to the final flush.
Foliar sprays for veg and the flip, outside the feed line.
Put it side by side
Where both ranges have a product for the same job, the fair answer is a test in your own room. Here’s what to watch and how to keep it fair.
Keeping it fair
- Same plants. Clones off the same mother, same cultivar, same age.
- Same room. Same light, climate, media, pot size and watering.
- Same base. Keep the base feed and EC the same on both sides.
- One change. Change only the product being tested, and write down what you see each week.
Why each one fits
What the Bloom product does, the research behind that kind of input, and where it sits in a program that already runs.
One bottle for each stage
What it does. Pre in mid veg (weeks 2–3) and Ultra at the flip (flower weeks 1–2), both 1 ml/L weekly. Phat in flower weeks 3 and 4 at 2.5 ml/L. Ooze from week 5 through the final flush at 2.5 ml/L, overlapping Final at 1 ml/L in the last two weeks. These are timing tools, so there’s no study cited for them here.
How it stacks. Humboldt’s range is base, cal-mag, PK and support products. Bloom’s stage bottles go in over whichever base you run (our read: check runoff when you add anything new).
Kelp, tuna and sea minerals
What it does. Seaweed is southern bull kelp at 1 ml/L weekly, seedling through flush. Seafuel is tuna and kelp at 1 ml/L weekly, clone through late flower. Sea Minerals is trace minerals from sea water at 0.13 ml/L weekly, veg to bloom.
A review of seaweed extracts reports effects on germination, root growth, nutrient uptake and stress tolerance across many crops. It doesn’t test these bottles or cannabis.
How it stacks. Several Humboldt products list Ascophyllum seaweed as an ingredient, but none is a kelp tonic on its own. Bloom’s go in as separate small doses (our read).
Foliar sprays for veg and the flip
What it does. Groigen and Florigen go on at 20 ml/L as a spray, lights off, every few days as needed. Groigen runs seedling through veg; Florigen from the stretch to early bloom, stopping once buds set.
How it stacks. Sprays stay out of the tank, so they don’t touch the Humboldt base or EC plan at all.
Where each bottle sits in the cycle
Humboldt Nutrients’ timing in grey, Bloom’s in yellow, across shared stages of the grow.
| Stage | Root | Veg | Flip | 3–4 | 5+ | Last 2 | Flush |
|---|---|---|---|---|---|---|---|
| Humboldt Nutrients, per their pages | |||||||
| Humboldt Roots | |||||||
| Master A and B, 3-part, Oneness | |||||||
| Grow Natural | |||||||
| Bloom Natural (Humboldt) | |||||||
| Ginormous | |||||||
| Big Up Powder | |||||||
| Bloom, per Bloom’s weekly feed charts | |||||||
| Roots | |||||||
| Pre | |||||||
| Ultra | |||||||
| Phat (weeks 3 and 4) | |||||||
| Ooze (wk 5 to flush) | |||||||
| Final (with Ooze) | |||||||
| Seafuel | |||||||
| Seaweed · Humate · Sea Minerals | |||||||
| SWTNR | |||||||
| Cal-Mag | |||||||
| Groigen (foliar, as needed) | |||||||
| Florigen (foliar, as needed) | |||||||
| PK (as needed) | |||||||
| Silica | |||||||
Humboldt’s product pages name the stage but not the week. Humboldt Roots is for seedlings, propagation and early veg; Grow Natural runs the whole lifecycle; Bloom Natural and Ginormous are for flowering; Big Up is a bloom and finishing booster. Base products are hatched because the stages are our read. Their feeding charts are images we couldn’t read, so weeks aren’t shown. Bloom’s bars follow its weekly feed charts; pale Bloom bars are as-needed bottles.
Where the programs complement each other
Their base, Bloom’s stage bottles on top
Humboldt’s list has no veg, flip, bulking or finish additive. Pre, Ultra, Phat, Ooze and Final slot into the weeks over Master A and B, the 3-part or Oneness.
Six pairs worth a fair test
Cal-mag, PK, silicon, humic, rooting and carbs each have a bottle on both sides. A same-room test, one change at a time, is the honest way to pick (our read).
Foliars and sea inputs fill the open jobs
No foliar spray, standalone kelp tonic or sea-mineral product shows on Humboldt’s list. Groigen, Florigen, Seaweed, Seafuel and Sea Minerals cover those without touching their base.
Already covered
- Base feed. One, two and three-part mineral bases, plus a soil-only natural kit.
- Cal-mag, PK and silicon. Calyx Magnum, Equilibrium, Ginormous, Big Up and Structural Integrity.
- Root zone. Humboldt Roots, Hum-Bolt, FlavorFul, Myco Madness and Prozyme.
- Extras. Honey ES carbs, Verde nitrogen (16-1-2) and Sticky wetting agent.
Stays exactly as is
- Their base. Master A and B, the 3-part, Oneness or the Naturals.
- Myco Madness and Prozyme. Bloom has no inoculant or enzyme product.
- Sticky and Verde. Nothing in Bloom’s range does these jobs.
- The overlap bottles. If they’re working in your room, keep them, or test Bloom’s next to them.
Background, science and sources
Who Humboldt Nutrients are
Humboldt Nutrients sells plant nutrients and additives online and through a separate wholesale portal. Its growers page says it serves cannabis growers in the United States; the pages we read don’t give an address, founding date or owner.
The shop lists 27 items: one, two and three-part bases, a soil-only natural kit, cal-mag, PK boosters in liquid and powder, a silicon additive, humic acid products, a bacteria and mycorrhizal blend, a media cleaner, a wetting agent, a carbohydrate additive and a nitrogen supplement. They publish four basic feeding charts.
Sources: Home · All products · Feeding charts · Growers
What each company brings
Humboldt Nutrients: One, two and three-part bases, a soil-only natural line, cal-mag, PK, silicon and humic products, a microbial blend, media cleaner, wetting agent and printed feeding charts.
Bloom: one additive for each stage of the crop, seaweed, humic and sea mineral inputs, foliar sprays, and weekly feed charts for soil, coco and hydro. Rates and timing are on every product page.
Cropping Solutions, the other brand under Agricultural Organics, isn’t part of this report.
Dose basis: how each side counts
Most Humboldt product pages print the guaranteed analysis but not a rate; Verde’s says 1–2 teaspoons per gallon. Their rates sit on four feeding charts. Bloom prints ml per litre on a weekly feed chart.
The analyses differ too, so matching bottle volume side to side isn’t a like-for-like dose.
Mix calculator
Rates as printed on each company’s page (1 US gallon is 3.785 L). Bloom’s rates are per litre of nutrient solution, dosed weekly per its feed charts. Pick a product and your tank size.
Potassium in the plantWell supported
Hasanuzzaman and colleagues (2018) review potassium’s roles in plants, including carbohydrate metabolism, enzyme activation, stomatal control and stress tolerance.
Why it matters here: Ginormous, Big Up and Bloom’s PK are all phosphorus and potassium products. The review is general plant science and doesn’t compare products or timing.
Silicon in the plantWell supported
Luyckx and colleagues (2017) review what’s known about silicon in plants, with sections on easing abiotic stress such as salinity and drought, and on biotic stress.
Why it matters here: Structural Integrity and Bloom’s Silica both add silicon. The review doesn’t test either product.
Humic acid and rootsWell supported
A major review links humic substances to changes in root structure and function tied to nutrient uptake, including more lateral roots.
Why it matters here: Hum-Bolt, FlavorFul and Bloom’s Humate are all humic acid products. The review doesn’t test any of them.
Sources, all viewed 5 November 2026
Humboldt Nutrients: Home · All products · Feeding charts · Master A · Master B · Grow (Humboldt) · Micro · Bloom (Humboldt) · Oneness · Grow Natural · Bloom Natural · Deuce Deuce · Equilibrium · Calyx Magnum · Ginormous · Big Up Powder · Structural Integrity · Humboldt Roots · Hum-Bolt · FlavorFul · Humboldt Honey ES · Myco Madness · Prozyme · Humboldt Sticky · Verde · Growers
Bloom: Roots · Pre · Ultra · Phat · Ooze · Final · Seafuel · Seaweed · SWTNR · Humate · Cal-Mag · Groigen · Florigen · Sea Minerals · PK · Euro · Grow · Flower · Silica · OrganiShield
Last checked 5 November 2026. Public information only. Not affiliated with, endorsed by or approved by Humboldt Nutrients; product names belong to their owners. Please confirm current details with the manufacturer. Corrections: nathan@bloomyellowbottles.com. All Fit Reports