Like magnetic. Cover the hole with a small piece of Rockwool to create a dark, moist environment. The High Will Keep Your Motivated All Day Long.  Source: <a href=https://doska-ua.biz/2024/02/07/the-seed-vault-a-journey-into-cannabis-cultivation>https://doska-ua.biz/2024/02/07/the-seed-vault-a-journey-into-cannabis-cultivation</a>