Tissue culture plantlets 'hardening off' procedures

Below are several different methods for deflasking and hardening off your tissue culture plantlets. The process is easy, but a few simple rules need to be followed. For a better understanding we give examples of several methods.

When you receive your plants
Your microplants have just arrived and you don't know what to do with them. Don't worry too much!! Nothing is going to happen with them too quickly, so you have plenty of time to read all this information and if you have any questions you can contact us by email. Your microplants are used to a controlled climate. You need to provide some of this for your plants to survive.
They will not tolerate bright light equivalent to more than 30% sunlight. (20% is ideal).
They will not tolerate high temperatures, such as over 30 deg C or low temperatures, such as below 15 deg C (25 deg C is ideal).
They will only have enough food and space in the tube for 2 weeks growth. Growth can be slowed by lowering the temperature to 20 deg C.
The perfet way to keep them would be at 20-25 deg C, under cool fluorescent light (30 cm distance), but this can be improvised on.

General theory Plants grown in tissue culture are usually received in media filled plastic containers: a sterile environment with high humidity. While a light cycle is used to promote growth in explants, they only photosynthesise at approximately 10% of normal photosynthetic capacity: most of the nutrients they receive come from the plant growth media. Therefore explants need to learn to survive in a non-sterile environment with lower humidity and higher light levels and switch from relying on media nutriments and learn to photosynthesise to provide their own food source (switch from almost completely heterotrophic to almost completely autotrophic). Loss of some explant material during the hardening out process is inevitable: 5% is usual- +10% would cause a rethink in your hardening out strategy. Cheap, recycled black multi trays are one of the best ways to start the hardening out process in explants. Consider wearing latex gloves during this procedure: downside is increased friction on plants when potting out, upside is protection from pathogens on your hands. Use of plastic disposable sterile forceps is also a good idea.

The special method for deflasking Apocynaceae and Rubiaceae tissue cultured plants

(for Mitragyna speciosa, Pausinystalia yohimbe, Tabernanthe iboga)

Version 1: Equipment intensive


Version 2: Low budget


The professional method for deflasking most species of tissue cultured plants. (for all other species)