Pricking out seedlings:
If seedlings are too densely packed together, thin them out to give the remaining plants enough space to develop before they are planted out in the garden. Plants are ready for transplanting when they show their first true leaves. Small plants withstand transplanting better than larger ones, the shock being far less at the earlier stage.
When the seedlings are large enough to handle, prick out and transplant. Do this by gently prising out a few seedlings with a pointed knife. To transplant, take each seedling between thumb and forefinger, and plant into holes made with a pencil in damp growing mix. Lower the roots into the hole and firm the growing mix gently
Pinching out seedlings:
Once the young plants have settled into their new home, it is time to nip plants in the bud, as the saying goes. This means pinching out the growing tip to force the plant to branch instead of allowing it to become tall and spindly. It can easily be done with thumb and forefinger when the plants are young but, if they are allowed to become sturdy, it may be necessary to use secateurs.