Growing blue turmeric (also known as Curcuma caesia) at 2,780 feet elevation in Glenwood, Hawai‘i, inside a greenhouse with raised beds is an excellent setup. Here’s a step-by-step guide tailored for your location and environment:
1. Choose Your Planting Material
- Use fresh rhizomes (not dried).
- Select plump, disease-free pieces with visible buds or “eyes.”
2. Soil Requirements
- pH: 6.0 to 6.5 (slightly acidic)
- Texture: Loose, well-drained, rich in organic matter
- Ideal mix for raised beds:
- 50% Hawaiian Volcanic Organic topsoil or compost
- 25% coco coir or peat moss
- 25% black cinder (for drainage)
- Add a handful of biochar per square foot if available
3. Planting Method
- When to plant: Early spring to early summer (now is a good time)
- Depth: 2–3 inches deep
- Spacing: 12–18 inches apart
- Lay the rhizomes horizontally, buds facing up
4. Watering
- Keep soil consistently moist but not soggy.
- Drip irrigation or hand watering with filtered rainwater is ideal.
5. Light Requirements
- Partial sun to dappled shade
- Your greenhouse is perfect if it allows filtered light and avoids scorching midday sun
Organic Fertilizers for Blue Turmeric
Apply these throughout the season:
|
Fertilizer |
Use Timing |
Application Notes |
|
Composted chicken manure |
Pre-plant + mid-season |
Rich in NPK; mix into soil before planting |
|
Monthly |
Enhances microbial life and breaks down nutrients |
|
|
Bone Meal |
Pre-planting |
High phosphorus – promotes rhizome and root development |
|
Fish emulsion (diluted) |
Bi-weekly foliar spray |
Gentle nitrogen boost during vegetative growth |
|
Banana compost or wood ash (small amounts) |
Monthly |
Potassium and minerals; improves rhizome development |
|
Crushed volcanic rock (azomite or basalt dust) |
1–2x per season |
Micronutrients and silica for cell strength |
Maintenance Tips
- Mulch with dried leaves or straw to keep moisture in and weeds out.
- Watch for fungal issues (high humidity) – HOCl foliar misting can help prevent mold/mildew.
- Harvest after 8–10 months when leaves yellow and start to die back.
Blue Turmeric Organic Fertilizer Schedule
Growing Duration: ~8–10 months
Planting Time: March–May (best in Hawai‘i)
Location: Greenhouse, raised beds, filtered light
MONTH 0 – Pre-Planting (1–2 Weeks Before Planting)
Amend Raised Bed Soil:
- Composted Chicken Manure – 1 inch layer mixed in
- Bone Meal – ½ cup per square foot
- Hawaiian Bokashi Inoculant – 1 tbsp per square foot (lightly mix into topsoil)
- Azomite or Crushed Volcanic Rock Dust – ½ cup per square foot
Water well and let the bed sit for 1–2 weeks to allow microbial activity to activate.
MONTH 1–2 (Early Growth – Sprouting to Leaf Growth)
Bi-Weekly (Every 2 weeks):
- Fish Emulsion Foliar Spray – 1 tbsp per gallon, spray leaves and soil
- Organic Sustain Granular Fertilizer (2-2-2) – Lightly scratch in ½ cup per plant base
- Optional: Add 1 tbsp of Bokashi per plant base every 2 weeks
MONTH 3–5 (Vegetative Growth Phase – Lush Leaves)
Monthly:
- Top Dress with Organic Chicken Pellets – ½ cup per plant
- Reapply Azomite – ¼ cup per square foot
- Optional Foliar: HOCl mist weekly to prevent mildew
Bi-Weekly:
- Continue Fish Emulsion (1 tbsp/gallon)
- Optional: Add banana peel compost or wood ash around the plant (low dose for potassium)
MONTH 6–8 (Rhizome Bulking Phase)
Monthly:
- Organic Sustain (2-2-2) – ½ cup per plant
- Bone Meal or Rock Phosphate – ¼ cup per plant for strong rhizome development
Bi-Weekly:
- Fish Emulsion OR switch to Seaweed Extract for potassium
MONTH 9–10 (Final Maturation + Harvesting)
Stop fertilizing completely
- Let the plant naturally yellow and dry back
- This signals rhizomes are ready for harvest
Optional Boosters
- Silicon Minerals (in your custom fertilizer) – helps strengthen plant structure
- Bokashi Tea or Compost Tea – Use monthly as a soil drench to stimulate microbes
Frequently Asked Questions (FAQ)
Q1: Can I grow blue turmeric at high elevation in Hawai‘i?
A: Yes! Blue turmeric (Curcuma caesia) grows well at elevations like 2,780 feet in Glenwood. Your cooler climate combined with greenhouse protection creates an ideal environment for steady, vibrant growth.
Q2: What’s the best soil pH for blue turmeric?
A: Aim for a slightly acidic soil with a pH between 6.0 and 6.5. This helps maximize nutrient uptake and rhizome development.
Q3: What’s the best soil mix for raised beds?
A: A loose, rich, and well-drained mix works best:
- 50% compost or Hawaiian Volcanic Organic topsoil
- 25% coco coir or peat moss
- 25% black cinder or other drainage material
- Optional: Add biochar and volcanic rock dust for minerals
Q4: How do I fertilize organically for best results?
A: Use a monthly schedule combining:
- Composted chicken manure
- Bone meal (pre-plant and mid-season)
- Organic Sustain (2-2-2) or similar balanced organic fertilizer
- Hawaiian Bokashi inoculant
- Fish emulsion or seaweed extract as bi-weekly foliar spray
Q5: What’s Bokashi Tea and how do I use it?
A: Bokashi Tea is the liquid drained from a Bokashi compost bin. Dilute 1:100 (1 tablespoon per quart) and apply to soil.
Do not spray on leaves — it’s too acidic.
Q6: How do I make Compost Tea for blue turmeric?
A: Mix:
- 1–2 cups compost
- 3–4 gallons rainwater or dechlorinated water
- 1 tbsp unsulfured molasses
Let it brew with aeration for 24–36 hours. Use it as a foliar spray or soil drench within 6 hours.
Q7: When do I harvest blue turmeric?
A: After 8–10 months, when the leaves begin to yellow and die back naturally. This signals mature, harvest-ready rhizomes.
Q8: How often should I water it?
A: Keep the soil evenly moist — not soggy. Drip irrigation or filtered rainwater works great. Avoid waterlogging, especially in raised beds.