Transplanting and caring for tissue culture bromeliads
Tissue culture (tc) plants are disease free when you receive them, meaning they have been checked and certified as free from any disease, before being shipped. Many confuse this with ‘disease-resistant’, which is not entirely correct. Hardened-off tissue culture plants are certainly more robust and have more vigour than conventionally acquired plants, owing to their highly regulated, ‘pampered’ beginnings. But freshly deflasked tc plants have very low resistance to disease, and have yet to develop the waxy cuticle on their leaves that helps to control transpiration (rate at which moisture is lost), pretty much like a new-born baby. They are therefore vulnerable to dehydration at humidity less than 70% especially in the first few weeks after deflasking.
Simple step by step Deflasking procedure:
1. Open the flask (plastic container) in a shaded, cool, and most importantly, clean environment.
2. Carefully remove the plants and rinse off any gel remaining on the roots. It is important that this is removed, as it will encourage fungal growth once exposed to non-sterile conditions. A useful technique is to open the flask and pour some lukewarm water in it. Swirl the flask so that the entire clump of plants, along with jelly, loosens up and starts to swirl with the swirling action.
Then carefully tip this plant and gel clump into lukewarm water, and then carefully separate jelly from roots/plants base. This not only makes it easier to clean off all the gel, the roots tend to suffer less damage this way.
3. Remove plantlets from only one flask at a time and plant them quickly. It is best to plant in the morning, before temperatures begin to climb significantly.
4. Use sterilised potting mix (if possible) with relatively low nutrient concentration. We use peat moss + perlite (50:50). Ensure the potting mix has been watered, but is not too wet.
5. Avoid planting in a potting mix that is hot (>25°C). During the first few weeks of growth, it is beneficial (but not required) to maintain air temperatures within a range of 18-23°C.
6. Carefully plant each plantlet in the seedling tray cell, firming it in gently and ensuring that the base of the plant is in good contact with the potting mix. Any existing roots should be buried, and more will form if these are damaged or absent. Transfer this tray to a polyhouse, hothouse or humidity chamber, maintaining humidity at around 70%.
If a humidity chamber is not available, a styrofoam box with two inches of wet sand at the bottom and a sheet of glass over the top will serve the purpose just as well. Cling wrap can also be used over the top with a few holes punched in it to allow air circulation. Sit the seedling tray on the wet sand. You can fit one seedling tray (48 cavities) in this makeshift chamber.
For more seedling trays, a small polytunnel makes a good humidity chamber. It is portable and very easy to install. You can fit eleven 48-cavity seedling trays (approx. 500 plants) in it. This tunnel can be reused for growing herbs, raising seeds etc.
7. After planting, you may spray the plants with a MoistureTrap solution for better results. This solution forms a protective film over the leaves and reduces rapid moisture loss from these baby plants, leading to faster hardening off. This product is also useful against frost-burn, sunburn, salt spray, windburn and transplanting losses.
8. Keep the trays at 20-22°C in filtered light (direct sun will turn the mini-greenhouse into a mini-pressure cooker). By late spring, through summer and early autumn, shade screens must be used to reduce light levels. Up to 50% shade can be used during the peak of summer.
9. As the plants develop, a mild liquid fertiliser can be sprayed to optimise plant growth rates. We use 20ml of 100% seaweed solution diluted in 10L of water every week or fortnight depending on the requirement.
We provide seedling trays, mini polytunnels, and MoistureTrap at discounted rates when you buy tc plants from us. Please contact us for the prices.
This information is produced as a guide only for Australian/New Zealand conditions and application of any techniques described is at your own risk. For further details or an application to your particular circumstances, please contact your local advisor