Any seedlings raised in trays should be transplanted into larger containers before they become overcrowded; this is known as pricking off or pricking out. Seedlings will become weak and spindly if deprived of sufficient light or space, and transplanting them to another container will enable them to continue to develop until they are ready for planting out in the garden. Pricking out will also help to discourage fungal diseases such as damping off.

Method

As soon as the seedlings are large enough to handle and their first pair of 'true' leaves are well developed, they may be pricked out. Compartmented plastic packs or small pots (no more than 6 cm (3 in) in diameter), are perfect for individual seedlings; larger trays or pots may be used for several plants.

Step 1

Fill the new containers with a loam-based potting compost and firm gently to remove any air pockets.

Step 2

Tap the tray of seedlings against a bench or table top to loosen the compost slightly, then remove it intact from the container.

Step 3

Carefully separate the seedlings, holding them gently by their seed leaves to avoid bruising the foliage, stems, or growing tips. Loosen them from the soil with a widger or other small implement, taking great care not to damage the roots. You may need to plant small seedlings, such as lobelia, in little clumps as they are too tiny to be handled separately.

Step 4

Then, carefully lift each plant from the soil, keeping plenty of the moist seed compost around the roots to ensure that there will be little or no hindrance to growth when the seedlings are replanted. Discard any weak, unhealthy-looking seedlings.

Step 5

Use a dibber to make holes in the compost 4-5 cm (1 1/2-2in) apart, roughly to the same depth as the seedlings were planted in their old pot or seed tray. Place a seedling into each hole. Make sure that all the roots are covered with compost, then gently firm in each seedling using fingers or a dibber, and tap the container to settle the compost.

Step 6

When each container is full, water it from a can fitted with a fine rose to settle the compost around the roots. Cover the plants with clear plastic for a few days to increase the humidity around the seedlings whilst they re-establish, but make sure that the plastic does not touch the leaves as this may encourage rotting.

Step 7

Seeds that have been sown singly in packs or space-sown will not need pricking out and may be hardened off before planting out.

Step 8

After a month to six weeks, feed the seedlings with a weak liquid feed; you may need to do this sooner if they have been planted in a peat-free compost.