Propagation plug or starter block: choose the next step
A plug and a starter block have different roles. Check the medium, root development and dimensions before moving young plants into a larger block or a pot.
Decide where the plant goes after propagation
A plug is a compact starter medium. A larger block provides more growing medium for the next stage. You can also continue in a pot with a suitable mix. Plan that next step so you can check dimensions and watering.
Within Propagation supplies, you will find Propagation plugs, Rockwool starter cubes and small pots. A Jiffy peat pot is a container and needs a different approach from a rockwool block. One product does not automatically replace another.
Read outer dimensions and hole size separately
The Grodan large-hole starter block has outer dimensions of 7.5 × 7.5 × 6.5 cm and a 38 mm hole. Agra Wool starter blocks come in the same outer size with 28 or 38 mm holes. Choose the exact version.
Hole diameter does not establish the full shape or depth of the fit. Check plug and block together. Avoid forcing a root plug into a small opening and do not assume universal compatibility because both products are propagation media.
Assess roots before moving the plant
Look at root distribution throughout the plug and the condition of the young plant. A weak or barely rooted plug differs from an evenly developed root ball. A fixed calendar day is therefore not a reliable transplant rule.
Limit damage when handling and keep the root plug intact where possible. Have the chosen pot or block ready before removing plants from the tray.
Prepare each medium correctly
Rockwool and soil are different media. Follow the preparation and feeding approach for the exact product. Avoid applying a fixed pH, EC or soaking time from instructions for another block or plant stage.
Check even wetting of the new medium and drainage of excess water. A prepared block still needs a suitable feeding programme and follow-up checks.
Review the setup after transplanting
Moving changes the volume of medium surrounding the roots. Reassess moisture, drainage and plant condition. Do not automatically transfer the watering routine from a small tray to a larger block or pot.
Explore Plant pots for the next pot and use the pot volume guide for capacity and dimensions. Continuing in soil or coco? Read our soil or coco guide. Through Growing media & pots, you can compare starter media and growing substrates.