Acclimatisation: getting plantlets out of the jar alive

Inside the vessel, a plantlet has it easy: close to 100% humidity, sugar in the medium, steady temperature and no germs. Its leaves have a thin wax layer, its pores (stomata) don't close well, and its roots have never met real soil. Take it straight out and it dries up within hours. Acclimatisation is the slow handover to normal life.

A simple routine

1. 1Gently wash the medium off the roots with lukewarm water. Leftover sugar invites fungus.
2. 2Plant into a light, well-drained, clean mix such as cocopeat with perlite.
3. 3Put the trays under a clear cover or in a mist chamber so humidity stays high.
4. 4Keep light low for the first week and increase it gradually.
5. 5Over two to four weeks, open the cover a little more each day to lower humidity.
6. 6Once new leaves appear and plants stand without wilting, move them to normal nursery conditions.

What goes wrong

• Wilting on day one: humidity dropped too fast.
• Rotting at the base: the mix stays too wet or the roots weren't cleaned.
• Leaf scorch: light increased before the plant was ready.
• Slow growth: the plantlets came out without good roots. Fix it at the rooting stage.

Good acclimatisation is where a tissue culture operation earns its reputation. A thousand healthy plantlets in jars mean nothing if half are lost in the tray.