1. What Is Grotek?
Grotek is a Canadian fertilizer brand founded in 1998 by Greenstar Plant Products. Grotek’s philosophy is to help amateur growers achieve professional results with easy-to-use, highly effective, and affordable products.
Grotek offers 4 separate feeding charts: soil, hydro, autoflower, and organic. Each chart is optimized for its respective growing method.
AZ Growshop is the Authorized Grotek Distributor in Southeast Asia.
2. Main Product Lines
2.1 Solo-Tek Grow & Bloom
- Solo-Tek Grow (6-3-7): base nutrient for the veg stage, 1-part, easy to mix
- Solo-Tek Bloom (3-8-8): base nutrient for the bloom stage, 1-part
- Advantage: no need to mix A+B, perfect for beginners. Just 1 bottle per stage.
2.2 Monster Series — Boosters
- Monster Grow Pro (NPK: 18-36-1, powder): powerful veg growth
- Monster Bloom (PK 50-30, powder): extremely potent bloom booster, used mid-to-late bloom
- Bud Fuel Pro (NPK 1-3-4, liquid): stimulates stage transition
- Heavy Bud Pro (NPK 2-0-5, liquid): late bloom support, supplemental K
2.3 Grotek Organics
- Pro-Silicate: organic silicon, strengthens stems and leaves
- Vitamax Pro: micronutrients + amino acids
- Cal-Max: CalMag, especially essential for coco coir
3. General Feeding Schedule (for Soil)
Veg Stage (Weeks 1–4):
- Solo-Tek Grow: at the soil rate on the label (start low, increase gradually)
- Monster Grow Pro: at the label rate (from week 2)
- Cal-Max: 1 ml/L (if using coco or RO water)
Transition Stage (Week 5 — Pre-flower):
- Reduce Solo-Tek Grow
- Begin Solo-Tek Bloom at the low end of the label rate
- Bud Fuel Pro: at the label rate (one of the 3–4 applications allowed for the whole crop)
Bloom Stage (Weeks 6–10):
- Solo-Tek Bloom: at the soil rate on the label
- Monster Bloom: 0.1–0.2 g/L (from bloom week 4 through bloom week 7 — see section 4, PK booster)
- Heavy Bud Pro: 2 ml/L (3–4 applications in total for the whole crop, not every watering)
- Bud Fuel Pro: at the label rate (counts toward the same 3–4 total — do not use at every watering)
- The 3–4 application limit on Heavy Bud Pro and Bud Fuel Pro is set by the manufacturer’s label, not by us. Heavy Bud Pro also declares 0.1% boron.
Final Week (Flush):
- Water with correctly pH’d water only, or use Final Flush if available
- Note: Monster Bloom maximum is 0.3 g/L. Exceeding this will cause nutrient burn and lockout.
4. Featured Products & Dosage
Monster Bloom — PK 50-30 soluble powder. Grotek’s most powerful booster.
- Dosage: 0.1 g/L (bloom week 4) → 0.2 g/L (bloom weeks 5–7) → stop 1 week before harvest
- Use once per week, not every watering
- Combine with Heavy Bud Pro to balance K and N
Cal-Max — Grotek’s CalMag, containing Ca, Mg, and supplemental N.
- Dosage: 1–2 ml/L, every watering
- Use throughout both veg and bloom
5. Practical Tips from AZ Growshop
- Start at 50% of the recommended dose, then increase gradually based on plant response
- If you see burnt leaf tips (nutrient burn), reduce EC immediately
- Monster Bloom is very strong — many users overdo it. Less = better
- Solo-Tek is 1-part, no need to add anything else if you’re just starting out
- Measure pH after mixing: Grotek tends to push pH up, adjust down to 5.8–6.2
- Add nutrients to water, NEVER pour water into concentrated nutrients
6. Common Mistakes
- Using Monster Bloom too early (bloom weeks 1–2): the plant isn’t ready to absorb high PK
- Forgetting Cal-Max when using coco → early Ca/Mg deficiency
- Overdosing Monster Bloom → lockout of multiple micronutrients
- Not reducing Grow when switching to Bloom → excess N, delayed flowering
- Using the hydro chart for soil → dosage too high, root burn
References
- Grotek product pages and labels (grotek.com), read 3 September 2026: NPK values, the Monster Bloom, Heavy Bud Pro and Cal-Max doses, and the 3–4 application limit.
- Collado Vidal E. How to use the Grotek feeding charts. Grow Barato / GB The Green Brand. gbthegreenbrand.com
- Alchimia Web (2024). How to use Grotek feeding charts. alchimiaweb.com
The information in this article is for educational and reference purposes only. Growing cannabis must comply with the applicable laws of your country. In the Kingdom of Thailand, comply with the Notification of the Ministry of Public Health Re: Controlled Herbs (Cannabis), B.E. 2568 and Ministerial Regulation B.E. 2569.