Starting Off Seeds – A Step-by-Step Guide

Starting Off Seeds – Step-by-Step Guide

Germinating seeds gives you more control than starting from cuttings, making it ideal if you don’t have a mother plant or want to begin with fresh genetics. Using a propagator and starter cubes helps maintain the perfect environment for healthy seedlings.

Preparation

• Always clean work surfaces and tools with disinfectant before starting.
• Use dechlorinated water (leave standing for 24 hours) when preparing cubes.
• Pre-soak Grodan Cuttings Seed Cubes with a nutrient solution (e.g. Vitalink Plant Start at 3–4ml per litre).
• Check CF with a Bluelab Nutrient Truncheon – aim for 4 CF if starting at 0 CF base.
• Check pH is between 5.5–6.6. Adjust with pH Down if required.

Step-by-Step: Sowing Seeds

1. Soak Grodan cubes in prepared nutrient solution for a few minutes.
2. Shake cubes gently to remove excess water.
3. Widen the existing hole slightly with a pipette to fit seeds easily.
4. Place one seed per cube, ensuring good contact with the moist rockwool.
5. Cover lightly with rockwool fibres to protect the seed.
6. Mist the cubes, sides, and lid of your propagator to create humidity.
7. Place cubes on a tray, close vents, and mist as needed to keep conditions stable.

Propagation Conditions

Keep temperatures at 22–26°C with no more than 4°C variance between day and night. Run lights for 18 hours a day, or use 24 hours of light if using a propagation-specific unit. Seeds typically germinate in 5–10 days, at which point the first leaves (cotyledons) will show.

Aftercare

Once seedlings are established, open vents gradually to harden them off. Remove the propagator lid entirely once plants are strong. When shells are discarded, transplant seedlings into larger cubes or pots.

Pro Tip

Always sow more seeds than you need. This ensures a backup supply so you can select the strongest seedlings for transplanting.

Summary

Starting seeds with the right preparation and environment maximises germination rates and sets plants up for vigorous growth. With clean tools, correct pH/CF, and controlled humidity, your seedlings will quickly establish strong roots and be ready for transplant.