Blossom Green Fertilizer 2-6-8
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Greenway Biotech · Made in California since 1989
Blossom Green 2-6-8.
The bloom-stage engine of your reservoir.
Blossom Green 2-6-8 is the dedicated bloom concentrate in our 4-part hydroponic system — a low-nitrogen, high phosphate and potash powder built to drive flowering, fruit set, and harvest quality. It dissolves completely for clean reservoirs and clog-free lines, is CDFA registered, and is independently lab tested for heavy metals.
Find your size → Calculate how much I need6%
Available phosphate (P₂O₅) to drive bud initiation
8%
Soluble potash (K₂O) for flower quality and weight
100%
Water-soluble powder — no sediment, no clogged lines
4part
Integrates with Cal-Mag, Grow Green, and Micro Green
01 / Choose your size
Right-sized for the job.
Blossom Green is sold as a dry powder. Each package dissolves into a matching volume of stock solution at the standard 1.8 lb per gallon concentration — so a package size maps directly to how much concentrate it makes. Pick a size based on your reservoir volume and how long you want a batch of stock to last.
| Package Size | Water to Mix | Stock Solution Yield | Best For |
|---|---|---|---|
| 1.8 lb | 1 gallon | 1 gallon concentrate | Small tents, single-reservoir home grows |
| 9 lb | 5 gallons | 5 gallons concentrate | Most popular |
| 18 lb | 10 gallons | 10 gallons concentrate | Multi-room grows, small commercial setups |
| 36 lb | 20 gallons | 20 gallons concentrate | Best value |
02 / Ideal applications
One powder.
Every bloom-stage system.
Blossom Green is formulated for root-zone feeding in soilless and recirculating systems. Rates below are starting points for peak bloom — always dial in by EC and plant response.
DWC / RDWC
Up to 20 ml/gal of stock solution at peak bloom. Monitor reservoir pH daily — heavy bloom-stage uptake can shift it quickly.
NFT Systems
15–20 ml/gal. Check EC twice daily; thin nutrient films concentrate as plants drink.
Ebb & Flow
15–20 ml/gal. Adjust effective strength by flood frequency — more frequent floods deliver more nutrient per day.
Coco Coir
10–15 ml/gal. Never let coco dry out, and always feed Cal-Mag Plus alongside — coco binds calcium continuously.
Aeroponics
Run at roughly 75% of standard strength. Fine misting delivers nutrients efficiently, so a lighter solution avoids salt buildup on roots.
Dutch Buckets
15–20 ml/gal. Maintain 10–20% runoff to keep salts from accumulating in the media.
03 / Why Blossom Green
Built for bloom.
Nothing wasted on leaves.
The 2-6-8 ratio deliberately tapers nitrogen and loads phosphate and potash — the two nutrients flowering plants demand most. Here is what that buys you.
6%
High available phosphate drives flowering.
Phosphorus powers ATP energy transfer, bud initiation, and flower density, and supports essential oil biosynthesis through the critical bloom window. For soil-grown flowering plants, Monopotassium Phosphate (MKP) 0-52-34 can serve a similar role as a standalone P-K booster.
8%
High soluble potash builds quality and weight.
Potassium drives photosynthesis efficiency, sugar transport to developing flowers, and cell turgor — the factors behind flower color, aroma, firmness, and harvest weight. Many liquid bloom formulas carry only 4–7% K, which can limit quality at peak bloom.
100%
Water-soluble powder, no settling.
Blossom Green dissolves completely for immediate nutrient availability — no sediment, no clogged drippers, and no vigorous shaking before every feed the way thick liquid concentrates require.
4part
Designed to work as a system.
Blossom Green is formulated to run alongside Cal-Mag Plus 2-0-0, Grow Green 4-2-6, and Micro Green 2-0-3. Every ratio in the feeding schedule is built around the four products together — no guesswork about compatibility.
$/gal
Concentrated dry format keeps cost down.
A dry concentrate carries no water weight, so you are not paying to ship water. Mixed at standard rates, Blossom Green is often a fraction of the cost-per-gallon of premixed liquid bloom products — and dry powder stored sealed has an exceptionally long shelf life.
04 / The science
Why phosphorus and potassium define your harvest.
2-6-8N-P₂O₅-K₂O
Low nitrogen · high available phosphate · high soluble potash
The shift from vegetative growth to flowering is a metabolic pivot. During veg, a plant pours energy into leaves and stems and demands nitrogen to do it. Once flowering begins, that priority changes — and a fertilizer that keeps pushing nitrogen can stretch the canopy at the expense of buds. Blossom Green's 2% nitrogen is a maintenance level: enough to sustain amino acid synthesis and healthy tissue, but not enough to drive new leaf expansion when the plant should be setting flowers.
Phosphorus, expressed on the label as available phosphate (P₂O₅), is the engine of that reproductive phase. It powers ATP — the molecule plants use to move energy — and it is central to bud initiation, flower density, seed and fruit maturation, and essential oil biosynthesis. Potassium, expressed as soluble potash (K₂O), is the quality nutrient: it regulates stomatal opening, drives sugar transport into developing flowers, and maintains cell turgor for firm tissue. Together, adequate P and K through bloom are what separate a thin, pale harvest from a dense, aromatic one.
Because Blossom Green is a fully water-soluble powder, those nutrients reach the root zone in immediately available ionic form — no granule breakdown, no waiting on soil microbes. That makes it well suited to the precise, fast-feedback environment of a hydroponic reservoir, where you adjust by EC and pH rather than by calendar.
For deeper coverage, see the function of phosphorus in plants and the function of potassium in plants.
05 / Application rates
Pick your stage.
Get your rate.
All rates below are milliliters of prepared stock solution per gallon of reservoir water, drawn from the Greenway Biotech 4-part feeding schedule. Use EC as your primary guide — calendar weeks are a reference, not a rule.
Complete 4-Part Feeding Schedule
Quick answer: At peak bloom, use 20 ml of Blossom Green stock solution per gallon of reservoir water, alongside Cal-Mag Plus and Micro Green.
| Growth Stage | Cal-Mag Plus | Grow Green | Micro Green | Blossom Green | EC Target | pH Range |
|---|---|---|---|---|---|---|
| Seedlings / Clones (Week 1–2) | 2.5 | 1.25 | 1.25 | 1.25 | 0.5–0.8 | 5.5–6.5 |
| Early Vegetative (Week 3–4) | 5 | 5 | 5 | 5 | 1.0–1.4 | 5.5–6.5 |
| Late Vegetative (Week 5–6) | 7.5 | 15 | 10 | 5 | 1.4–1.8 | 5.5–6.5 |
| Transition (Week 7–8) | 10 | 10 | 10 | 10 | 1.6–2.0 | 5.5–6.5 |
| Early Bloom (Week 9–10) | 10 | 5 | 10 | 15 | 1.8–2.2 | 5.5–6.5 |
| Peak Bloom (Week 11–13) | 10 | 0 | 10 | 20 | 2.0–2.5 | 5.8–6.5 |
| Late Bloom / Flush (Week 14+) | 5 | 0 | 7.5 | 15 | 1.5–2.0 | 5.8–6.5 |
Note: Never mix concentrated stock solutions directly together. Dilute each product into the reservoir water separately, in order — Cal-Mag Plus first, then Micro Green, then Grow Green (veg and transition only), then Blossom Green — and adjust pH last. Exact timing varies by crop species, light intensity, and environment; use EC readings as your primary guide rather than calendar weeks alone.
Stock Solution Preparation
Quick answer: Dissolve 1.8 lb of Blossom Green powder per gallon of warm water to make a concentrated stock solution.
| Product | Powder to Water | Concentration | Shelf Life |
|---|---|---|---|
| Cal-Mag Plus 2-0-0 | 2.5 lb → 1 gal | 2.5 lb/gal | 6+ months |
| Grow Green 4-2-6 | 1.7 lb → 1 gal | 1.7 lb/gal | 6+ months |
| Micro Green 2-0-3 | 1.5 lb → 1 gal | 1.5 lb/gal | 6+ months |
| Blossom Green 2-6-8 | 1.8 lb → 1 gal | 1.8 lb/gal | 6+ months |
Note: Dissolve powder in warm water (70–80°F) for the fastest, most complete dissolution, then allow the stock to cool to room temperature before dosing. Store stock solution in a sealed, labeled container out of direct light. Do not store Blossom Green stock in the same container as Cal-Mag Plus concentrate — concentrated phosphorus and calcium react to form insoluble calcium phosphate.
Hydroponic System Guidelines
Quick answer: Feed continuously in DWC and NFT; in coco and drip systems, feed one or more times daily and maintain 10–20% runoff.
| System Type | Feed Schedule | Special Notes | Reservoir Change |
|---|---|---|---|
| DWC / RDWC | Continuous | Monitor pH daily | Weekly |
| NFT | Continuous | Check EC twice daily | Weekly |
| Ebb & Flow | 2–4× daily | Adjust strength by flood frequency | Weekly |
| Drip / DTW | Multiple daily | Maintain 10–20% runoff | N/A |
| Coco Coir | 1–2× daily | Never let dry; always feed Cal-Mag | N/A |
| Aeroponics | ~15 min cycles | Use ~75% concentration | Weekly |
Note: Blossom Green is formulated for root-zone feeding, not foliar spraying. Avoid foliar application of the concentrated bloom solution. If EC climbs above the target range at peak bloom, top off the reservoir with plain pH-adjusted water rather than adding more nutrient solution.
06 / How to use & calculate
Mix the stock.
Dose the reservoir.
Watch your EC.
Blossom Green works in two steps — prepare a concentrated stock solution once, then dose that stock into your reservoir at each fill. The calculator does the math for any reservoir size and stage.
-
01
Prepare the stock solution
Dissolve 1.8 lb of Blossom Green powder into 1 gallon of warm water (70–80°F) and stir until fully dissolved. Let it cool to room temperature, then store it sealed, labeled, and out of direct light. Shelf life is 6+ months.
-
02
Mix into the reservoir in order
Fill the reservoir with fresh water and add stock solutions one at a time, stirring between each: Cal-Mag Plus first, then Micro Green, then Grow Green (veg and transition stages), then Blossom Green. Never combine concentrates directly.
-
03
Check EC, then adjust pH last
Measure EC with a calibrated meter against the target for your stage and adjust volume if needed. Adjust pH to 5.8–6.5 during bloom as the final step. At peak bloom, if EC drifts high, top off with plain pH-adjusted water.
-
04
NOT for foliar spraying
Blossom Green is designed for root-zone feeding. Do not foliar-spray the concentrated bloom solution — the phosphate-and-potash profile is built for reservoir dosing, not leaf application.
07 / Compare
Four bloom options.
Different jobs.
Blossom Green is the system-integrated bloom formula. Depending on your setup, a standalone P-K salt or a crop-specific one-part formula may fit better. For broader context, see the best fertilizers to use in hydroponics.
| Product | Type | Nitrogen | Best For | Notes |
|---|---|---|---|---|
| Blossom Green 2-6-8 (this product) | Dry powder, system component | 2% (maintenance) | Bloom stage in a 4-part hydroponic program | Dissolves fully; built to run with Cal-Mag, Grow Green, Micro Green |
| Monopotassium Phosphate (MKP) 0-52-34 | Dry powder, single salt | 0% | Standalone bloom booster, soil or hydro | Concentrated P-K with no nitrogen; no micros — pair with a micro source |
| Potassium Sulfate 0-0-53 | Dry powder, single salt | 0% | Adding chloride-free potassium and sulfur | Potassium-only; supplies 17% sulfur; no phosphorus |
| Tomato Fertilizer 4-18-38 | Dry powder, complete one-part | 4% | Single-crop hydroponic systems | Crop-specific NPK plus micros in one product; less ratio flexibility |
08 / Decision
Is this the right
bloom fertilizer for you?
Blossom Green is purpose-built for one job: the flowering stage of a 4-part hydroponic program. Here is where it fits — and where another product fits better.
Best Choice For
- Flowering or fruiting crops in hydroponic, coco coir, or soilless systems
- Growers who want a complete 4-part system with a dedicated bloom formula
- Commercial operations needing a low cost-per-gallon, long-shelf-life concentrate
- Anyone moving away from liquid bloom nutrients and tired of shipping water
- Growers who dial in by EC and want precise, repeatable stock-solution dosing
Consider Another Product If
- You grow flowering plants in soil — try MKP 0-52-34 as a standalone bloom booster instead
- You only need chloride-free potassium and sulfur — use Potassium Sulfate 0-0-53
- You run a single-crop hydroponic system — a crop-specific formula like Tomato Fertilizer 4-18-38 or Strawberry Fertilizer 8-12-32 may be more targeted
- Your plants are still in vegetative growth — use Grow Green 4-2-6 until flower initiation
- You want every component together — the 4-Part Hydroponic Bundle bundles all four at one price
09 / Build the program
Blossom Green is one part.
These complete the system.
Each component is formulated to work together without compatibility issues. Run all four for complete, balanced nutrition from seedling through harvest.
Essential
Cal-Mag Plus 2-0-0
Calcium, magnesium, and chelated iron base. Always added first to prevent nutrient precipitation — especially critical with RO water and coco coir.
Veg StageGrow Green 4-2-6
Higher-nitrogen formula for vigorous vegetative growth. Build strong structure before switching to Blossom Green at flower initiation.
EssentialMicro Green 2-0-3
Complete chelated micronutrient package. Helps prevent hidden hunger across the entire grow cycle, including the high-demand bloom stage.
Best Value4-Part Hydroponic Bundle
All four components together at a bundled price — everything you need from seed to harvest in a single order.
10 / Safety & handling
Read this before
you mix.
Blossom Green is a concentrated fertilizer salt. A few simple precautions keep handling safe and your reservoir trouble-free.
- Wear gloves and eye protection when handling dry powder or stock solution. Avoid inhaling dust when opening bags — work in a well-ventilated area or wear a dust mask.
- Store in a cool, dry place in the original sealed bag or an airtight container, away from heat and direct sunlight. The powder is hygroscopic — seal it tightly between uses to prevent clumping. If it clumps, simply break it apart; efficacy is unaffected. Keep away from children and pets.
- Blossom Green is for root-zone feeding only — do not foliar-spray the concentrated bloom solution.
- Never mix concentrated stock solutions directly together. In particular, do not combine Blossom Green concentrate with Cal-Mag Plus concentrate — concentrated phosphorus and calcium react to form insoluble calcium phosphate. Always dilute each product into the reservoir separately.
- First aid — Eyes: flush with clean water for 15 minutes; seek medical attention if irritation persists. Skin: wash with soap and water. Ingestion: do not induce vomiting; contact Poison Control (1-800-222-1222) or seek medical attention. Inhalation: move to fresh air. Refer to the SDS for complete safety information.
11 / FAQ
Common questions.
Honest answers.
If your question isn't here, contact our team at questions@greenwaybiotech.com.
When should I switch from Grow Green to Blossom Green?
Switch at flower initiation — for photoperiod crops, that is typically the 12/12 light flip. During the transition period (weeks 7–8 on the feeding schedule), run equal parts Grow Green and Blossom Green at 10 ml/gal each. Then taper Grow Green down to 0 while increasing Blossom Green to 20 ml/gal by peak bloom. For more on bloom-stage feeding, see our guide to Flower Fertilizer 101.
Why is phosphorus emphasized in bloom formulas?
Phosphorus, shown on the label as available phosphate (P₂O₅), powers ATP energy transfer, bud initiation, flower density, maturity timing, and essential oil production. Without adequate phosphorus during bloom, a plant cannot efficiently convert light energy into the chemical energy needed for flower development. Learn more in our article on the function of phosphorus in plants.
Why does Blossom Green carry 8% potassium?
Potassium, shown on the label as soluble potash (K₂O), drives sugar transport, photosynthesis efficiency, and cell turgor — all of which influence flower size, aroma, color, and harvest weight. Many liquid bloom formulas carry only 4–7% K, which can limit quality during peak bloom. See our deep dive on the function of potassium in plants.
Do I have to use Cal-Mag Plus alongside Blossom Green?
Yes — always add Cal-Mag Plus to the reservoir first. Because Blossom Green is phosphorus-rich, calcium and phosphorus can react and become unavailable to plants if calcium concentration is high. Diluting Cal-Mag Plus into the reservoir first keeps calcium low enough that phosphorus from Blossom Green stays fully dissolved and plant-available.
Why can't I mix Blossom Green and Cal-Mag Plus concentrates directly?
In concentrated form, calcium and phosphorus react to produce insoluble calcium phosphate — essentially a cement-like sludge that clogs lines and wastes both nutrients. By diluting Cal-Mag Plus into the reservoir first, you keep the calcium concentration low enough that phosphate from Blossom Green stays in solution. Always dilute each concentrate into reservoir water separately.
What EC and pH should I target during bloom?
EC typically rises from 1.6–2.0 during transition to roughly 2.0–2.5 at peak bloom. Maintain pH between 5.8 and 6.5 during bloom, which is the optimal range for phosphorus availability. If EC climbs above the target, top off the reservoir with plain pH-adjusted water rather than adding more nutrient solution.
Can I use Blossom Green during the vegetative stage?
Yes, at low rates. The feeding schedule includes 1.25–5 ml/gal of Blossom Green during vegetative stages to provide a baseline of phosphorus and potassium for root and structural development. The full 20 ml/gal rate is reserved for peak bloom only — vegetative growth is primarily driven by Grow Green 4-2-6.
How do I store the dry powder?
Blossom Green is hygroscopic, meaning it absorbs moisture from the air. Keep the bag sealed tight between uses and store it in a cool, dry place out of direct sunlight. If the powder clumps, just break it up — efficacy is not affected. Stored properly, dry powder has an exceptionally long shelf life.
Is Blossom Green tested for heavy metals?
Yes. Blossom Green is independently lab tested for heavy metal content, with results consistently well below required limits, and it is registered with the California Department of Food and Agriculture (CDFA). A heavy metal analysis is available on request — email questions@greenwaybiotech.com.
Ready to feed?
Pick your bag. We'll ship it.
Blossom Green 2-6-8 ships in 1.8 lb, 9 lb, 18 lb, and 36 lb packages — from a single home tent to a multi-room commercial grow. Orders over $100 ship free, and every order is backed by our 90-day money-back guarantee.
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