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Is that a technique that involves using a vacuum to create a controlled environment for better germination of seeds? I think that method is often used in research and commercial plant production to improve seed germination rates. Especially for seeds that have hard coats or are difficult to germinate. Am I right?

Yes exactly, seeds can produced young sprouts fast if it is in Vacuum, thats what we always do here. ☺️

Now I see! I don't usually do this, just now because I really need moist for free water. =)

Vacuuming helps the soil always moist, the moisture of water will went to the soil. ☺️