If fungi or bacteria start to grow on the media we call it a contamination, because fungi and bacteria grow much faster than orchid seeds and they will kill them soon.

contaminations

More photos of contaminations:

There are many different reasons why contaminations can appear.

• sterilization of your tools, seeds or flasks failed
• problems in your sterile technique
• leaky caps

Many contaminations can be found 3 or 4 days after flasking seeds or plantlets (e.g. nodes). Here are some typical characteristics of contaminations:

• fast growing discs on the media
• fast growing "carpet" (looks like thin hairs or cotton)
• Media changes its color and becomes liquid

It is very important to detect a contamination very soon, because they can grow very fast. If you have found a contamination, you can try to replate "clean" seeds or protocorms to other flask. When you are culturing nodes, you can sterilize the node with 3% hydrogen peroxide (H₂O₂) for 15 minutes again and then place it on new media. If one of your flasks is contaminated and you are not able to rescue it on the same day, transfer the flask to a darker and cool place, because at this conditions the contamination grow a little bit slower.