28 September 2025
I had a discussion with Dixit Sir. In that discussion, it was decided that after spinach, we will grow Aster plants in the hydroponic system. For this, I need to find out which type of hydroponic system is suitable for Aster plants. Also, documentation has to be prepared on Aster plants, and after that, the next discussion will be held .
The link below refers to the Aster document :
Aster
- Botanical Name: Callistephus chinensis
- Common Name: Aster
- Family: Asteraceae
- Type: Annual ornamental flowering plant
- Origin: Native to China, widely cultivated globally for cut flowers and garden decoration.
Aster is popular for its vibrant, daisy-like flowers that come in a variety of colors such as purple, pink, red, white, and blue. It is highly valued in floriculture due to its long-lasting blooms and aesthetic appeal.
2. Plant Characteristics :
- Height: Typically 30–90 cm depending on variety and cultivation conditions.
- Leaves: Simple, lance-shaped, arranged alternately on the stem.
- Flowers: Composite flowers with central disc florets and surrounding ray florets.
- Blooming Period: Generally blooms in late summer to autumn (8–12 weeks after planting).
- Life Cycle: Short-lived annual, completing its life cycle in one growing season.
3. Uses:
- Cut Flower Production: Stems are long and sturdy, suitable for bouquets and floral arrangements.
- Ornamental Gardening : Ideal for beds, borders, and containers
- Research Crop: Due to its predictable growth, it is used in floriculture experiments and hydroponic research.
Aster in Hydroponics
- Aster (Callistephus chinensis) is a popular cut-flower crop.
- It grows well in soilless culture, but requires careful nutrient and EC management.
- Hydroponics helps get uniform flower size, better stem length, and controlled flowering.
1. Best Hydroponic Systems for Aster:
- NFT (Nutrient Film Technique): Good for leafy crops, but not ideal for long-term flowering plants like Aster (roots need more stability).
- DWC (Deep Water Culture): Roots may become too waterlogged → fungal risk.
- Drip Irrigation / Dutch Bucket (recommended):Provides stable root support (using cocopeat, perlite, or rockwool). Controlled nutrient supply.Best suited for flowering crops like Aster, Gerbera, Chrysanthemum.
Aster in DWC Hydroponics
Possible
- In DWC, roots stay directly in the nutrient solution → allows fast nutrient uptake.
- Aster can grow if proper aeration is provided.
Challenge:
- Risk of Root Rot – Flowering crops like Aster have a long growth cycle, and since roots remain continuously in water in DWC, the chance of fungal infections (Pythium, Fusarium) is high.
- Plant Support – Aster needs strong stems and support; in DWC, only net pots with Hydroton/coco chips provide support. For large flowering plants, this may be somewhat unstable.
- Nutrient Fluctuation – For long-term crops, maintaining a stable solution is difficult; EC and pH need frequent monitoring.
Precautions if using DWC
- Strong Aeration: 1–2 air stones in tank
- Water Temperature: 20–24 °C (warm water increases disease risk)
- Use Net Pots with Media: Hydroton + cocopeat/perlite mix for stem support.
- Disinfect System Regularly: Use H₂O₂ or other sterilizers for the root zone.
- Change Solution: Every 7–10 days.
Aster – Hydroponic Environmental Requirements :
| Parameter | Ideal Range | Notes |
| pH | 5.8 – 6.2 | Keep stable; check regularly; outside this range nutrient uptake decreases |
| EC (Electrical Conductivity) | 2.0 – 2.5 mS/cm | Too high → leaf burn; too low → poor flowering |
| Young seedlings | 1.8–2.0 mS/cm | |
| flowering plants | 2.3–2.5 mS/cm. | |
| Water Temperature | 20 – 24°C | Cooler water improves root oxygenation; warmer water → disease risk |
| Air Temperature | 18 – 24°C | Aster prefers mild, cool conditions; avoid frost |
| Humidity | 50 – 70% | Too high → fungal infection (Pythium, Fusarium) risk |
| Light | 12–14 hours/day | 200–300 µmol/m²/s (LED or sunlight); sufficient light promotes flowering |
| Other Notes | – | Long photoperiod helps uniform flowering; heat stress >26°C may reduce stem strength and flower quality |
EC (Electrical Conductivity) – 2.0–2.5 mS/cm
1. What EC Means:
- EC measures the total concentration of dissolved salts/nutrients in your hydroponic solution.
- Higher EC = more nutrients; Lower EC = fewer nutrients.
- Units: mS/cm (milliSiemens per centimeter).
- Ideal Range for Aster:
- 2.0 – 2.5 mS/cm is ideal for hydroponic Aster.
- Ensures the plant gets enough nutrients for healthy stem growth, leaf development, and flowering.
3. Effects of Too High EC (>2.5 mS/cm):
- Leaf Burn / Tip Burn: Excess salts cause osmotic stress; water moves out of leaf cells → burning at leaf tips.
- Stunted Growth: Roots may be damaged; nutrient uptake becomes inefficient.
- Reduced Flower Quality: Flower size and stem length may decrease.
4. Effects of Too Low EC (<2.0 mS/cm):
- Nutrient Deficiency: Plant doesn’t get enough macro- and micronutrients (N, P, K, Ca, Mg, Fe).
- Poor Flowering: Stems may be weak, fewer blooms, delayed flowering.
- Leaf Yellowing or Poor Leaf Development: Leaves may turn pale due to nitrogen or iron deficiency .
5. Managing EC in Hydroponics:
- Monitor Daily: Use a reliable EC meter.
- Adjust Nutrients Gradually: Add concentrated nutrient solution to raise EC or dilute with water to lower EC.
- Account for Crop Stage: Young seedlings may need slightly lower EC (1.8–2.0 mS/cm), while flowering plants can handle 2.3–2.5 mS/cm.
- Temperature Factor: Warm water increases nutrient uptake; adjust EC accordingly to avoid over-fertilization.
Aeration in DWC
- In a DWC (Deep Water Culture) system, the plant roots stay directly in the water (nutrient solution).
- If there is no oxygen in the water → the roots will “suffocate” and root rot will occur.
- Therefore, it is essential to maintain dissolved oxygen (DO) in the water.
What is an Air Stone?
- A small porous stone or mesh-like device commonly used in aquariums.
- It is connected to an air pump.
- Air comes from the pump → tiny bubbles come out of the stone.
- These bubbles dissolve oxygen into the nutrient water.
Aster in NFT System (Nutrient Film Technique)
Advantages :
- The nutrient film is continuously in contact with the roots → faster nutrient uptake.
- Saves water and nutrients.
- Clean and low-maintenance system.
Challenges for Aster :
- Plant Size & Growth Cycle – Aster is a long-duration crop (90–120 days), whereas NFT is mainly suited for short leafy greens (like spinach, lettuce, basil). In long crops, roots can block the NFT channels.
- Support System Needed – Aster stems and flowers are heavy, so extra plant support is required in NFT pipes.
- Root Space – Aster needs a deep and stable root zone. In NFT, roots stay in a thin nutrient film, which can form dense root mats and block the channels.
If we still want to grow Aster in NFT:
- Use wide channels (4–6 inch PVC pipes).
- Maintain plant spacing of 20–25 cm (avoid overcrowding).
- Add extra support sticks for flowers.
- Maintain EC range: 2.2–2.3 mS/cm (same as DWC).
- Clean channels regularly to prevent root clogging.
Standard Nutrient Requirement for Aster :
| Nutrient | Recommended Concentration (ppm) | Target ppm | Role in Aster |
| Nitrogen (N) | 150 – 180 ppm | 165 ppm | Vegetative growth, stem length |
| Phosphorus (P) | 40 – 50 ppm | 45 ppm | Root growth, bud initiation |
| Potassium (K) | 180 – 220 ppm | 200 pm | Strong stems, flower color & size |
| Calcium (Ca) | 140 – 160 ppm | 150 ppm | Cell wall strength, disease resistance |
| Magnesium (Mg) | 40 – 60 ppm | 50 ppm | Chlorophyll, prevents interveinal yellowing |
| Sulfur (S) | 50 – 70 ppm | 60 ppm | Protein synthesis, flower quality |
| Iron (Fe) | 2.0 – 3.0 ppm | 2.5 ppm | Prevents chlorosis |
| Manganese (Mn) | 0.5 – 1.0 ppm | 0.7 ppm | Enzyme activity |
| Zinc (Zn) | 0.05 – 0.1 ppm | 0.1 ppm | Hormone regulation, leaf expansion |
| Copper (Cu) | 0.05 ppm | 0.005 ppm | Enzyme activation |
| Boron (B) | 0.3 – 0.5 ppm | 0.4 ppm | Flower & seed development |
| Molybdenum (Mo) | 0.05 ppm | 0.05 ppm | Nitrogen metabolism |
Nutrient Requirement
- Vegetative stage: Higher nitrogen for leaf and stem growth.
- Flowering stage: Higher potassium and phosphorus for bud formation & flower quality.
- Micro-nutrients like Fe, Mn, Zn, B, Mo are essential for color and petal formation .
Link of Nutrient Source for Aster : https://docs.google.com/spreadsheets/d/1rqk6-aB_zssgVop405Xy473vgkeZ4Lzb/edit?usp=sharing&ouid=113141058233737100131&rtpof=true&sd=true
