Solving Our Shortages for Seedlings Act or the SOS for Seedlings Act This bill requires various activities to alleviate a shortage of tree seedlings. Specifically, the Forest Service must implement a national strategy to address the shortage by expanding the capacity of governmental and private nurseries. In addition, the Department of Agriculture (USDA) must carry out a loan program for state, tribal, or local governments; or private, nonprofit, or cooperative organizations to establish or expand facilities that grow, store, extract, or monitor tree seedlings. The bill also reauthorizes through FY2030 a program that permits USDA to establish and operate nurseries, purchase tree seeds or seedlings, plant trees, and otherwise support reforestation.