Garden Mythbusters Episode One: Do Seed Tray Humidity Domes Promote Mold and Fungus Growth?

Garden Mythbusters Episode One: 

Do Seed Tray Humidity Domes Promote Mold and Fungus Growth?

I am starting a new series that puts garden myths, old wives' tales and urban farmer legends to the test. This is somewhat scientific but mostly done to have some fun and to shed some light on the things we hear we should or shouldn't do in and around the garden. You be the judge!

If you like this series please let me know and certainly put some things you would like to be tested in the comments section.

I don't use humidity domes ever since the ugly day over 10 years ago... 'damping off' diseases hit my germinating lettuces and other plants. I thought it was a sterile starting mix. I thought I did the right thing. I used the dome as recommended by the manufacturer. I opened it daily.  More than once in fact! I bottom watered.  But they died as quickly as they sprouted.

I am not posing the question are humidity domes good or bad. I am not saying they cause mold or fungus. I am not talking about how you should use them. (In fact I don't use them). I am simply posing the question:

Do Seed Tray Humidity Domes Promote Mold and Fungus Growth?

The video shows you the set up and results. Not everyone can buy sterile mix. Remember gardening is global.  Spores come in from the air, water, tools, seeds, hands and other places. They are all around us. The bread is a known host of mold and fungus. Let's see if the dome promotes and environment for their growth.

One tray is used without the dome and the other uses the dome. They are treated equally in my grow closet for 10 days. The dome was opened regularly. Here are the results. You be the judge!