Spring onions, also called scallions, are a versatile and mild onion variety. These fast-growing greens don’t develop large bulbs, making them ideal for indoor hydroponics. A compact and low-maintenance crop, spring onions bring a fresh, oniony flavour to dishes without needing large garden space. With the use of an LED hydroponic setup, spring onions can thrive indoors, providing a continual harvest of fresh greens year-round.
As I’m just starting on this hydroponic journey, I’m excited to share my progress and learnings along the way. You can follow all updates and related posts in the Hydroponic Growing section of my blog. Let’s see what we can grow together!
Advantages of Hydroponic Spring Onion Cultivation
Growing spring onions in a hydroponic system offers several benefits:
- Controlled Environment: Indoor hydroponic systems regulate temperature, humidity, light, and nutrients, supporting consistent growth.
- Quick Maturity: Spring onions grow rapidly, typically ready for harvesting within weeks.
- Space-Efficient: Hydroponics eliminates the need for soil and uses minimal space, making it possible to grow a dense crop in compact systems.
With an LED hydroponic grow system, it’s easy to maintain the optimal conditions for robust spring onion growth.
Recommended LED Grow System
There are many LED hydroponic systems available, but models like the 8-pod system on Amazon or the 12-pod system offer excellent value. These systems provide efficient LED lighting with spectrum options and simple water management. Using one of these affordable systems, you can enjoy reliable indoor crop production without overspending.
Setting Up Hydroponic Spring Onions
Essential Nutrients
For hydroponic systems, the General Hydroponics Flora Series (FloraGro, FloraMicro, FloraBloom) is a dependable choice, offering balanced nutrients to sustain spring onions through all stages, from seedling to maturity.
Lighting Requirements
Spring onions benefit from LED grow lights that simulate daylight. For optimal growth:
- Seedling to Maturity: Maintain a lighting schedule of 16 hours of light daily, simulating longer daylight hours to promote strong leaf growth.
Temperature and Humidity Settings
- Temperature: Keep temperatures between 18-24°C to support healthy growth.
- Humidity: Aim for 50-60% humidity, suitable for leafy greens.
- pH Range: Maintain a pH of 5.5 to 6.0 for optimal nutrient absorption.
Spring Onion Growth Stages in Hydroponics
1. Germination and Early Seedling Phase
- Duration: 1-2 weeks
- Nutrient Mix: Add 0.5 ml of FloraGro and 0.5 ml of FloraMicro per litre of water, with no FloraBloom required.
- Lighting: Keep LED lights on for 16 hours per day.
- Temperature & Humidity: Ideal range is 18-24°C and 60-70% humidity.
- pH Management: Monitor pH regularly, adjusting to keep between 5.5 and 6.0.
Notes: Spring onion seeds should sprout within the first week. When seedlings reach a few centimetres in height, they’re ready for the vegetative phase.
2. Vegetative Growth Stage
- Duration: 2-5 weeks
- Nutrient Mix: Increase to 1.5 ml of FloraGro, 1 ml of FloraMicro, and 0.5 ml of FloraBloom per litre of water.
- Lighting: Continue with 16 hours of light per day.
- Temperature & Humidity: Keep temperature around 18-22°C and humidity at 50-60%.
- Water Change: Replace nutrient solution every two weeks to avoid build-up.
- pH Management: Maintain pH between 5.5 and 6.0.
Notes: During this stage, spring onions will establish more robust green stalks. Adjust nutrient levels as needed and check water levels frequently.
Complete Growth Schedule and Nutrient Chart
The amounts listed for FloraGro, FloraMicro, and FloraBloom are measured per litre of water. Adjust accordingly for the total volume in your hydroponic reservoir.
| Growth Stage | Duration | FloraGro (ml) | FloraMicro (ml) | FloraBloom (ml) | Lighting (Hours) | Temperature (°C) | Humidity (%) |
|---|---|---|---|---|---|---|---|
| Germination | 1-2 weeks | 0.5 | 0.5 | 0 | 16 | 18-24 | 60-70 |
| Vegetative Growth | 2-5 weeks | 1.5 | 1 | 0.5 | 16 | 18-22 | 50-60 |
Final Tips for Hydroponic Spring Onions
- Monitor Regularly: Check nutrient levels, pH, and general plant health weekly.
- Maintain Clean Equipment: Keeping the hydroponic setup clean will help prevent nutrient and mineral build-up.
- Harvest Tips: Harvest spring onions when they reach a desirable size (about 6-8 inches). You can trim the tops and allow them to regrow for multiple harvests.
