F14 Hardening off

For the last four to six weeks in the nursery the seedling trees need to be ‘taught’ how to survive outside the nursery where there is no shade and where it does not rain every day. This is called ‘hardening off ’.

If a shade has been built over the seedlings, gradually remove the shade over several weeks. Slowly reduce the amount of water. However, do not let the seedlings wilt in hot sun. If grown under a tree, move the seedlings to the edge of the shade so they are in full sun for part of the day.

A week or two before planting out, prepare planting holes. Dig a hole about half a metre deep (nearly knee deep). If possible, break up the hard rocky subsoil in the bottom of the hole and add a little manure. 

Discussion 

  • Discuss the benefits of ‘hardening off ’. Could this be done for vegetables growing in a nursery bed as well? 
  • What would happen to young trees which were planted out immediately without ‘hardening off ’? 
  • What would happen if young tree seedlings were planted straight into hard rocky soil? 
  • Discuss how deep planting holes should be for young seedlings. (They should ideally be at least twice the depth of the root ball and filled with good soil to enable the tree to have a good start.)