Q.Spaghetti Squash/Zucchini
Bought both plants at Home Depot. First year garden. Mushroom soil. Why are my leaves getting dark spots? Same on both plants. See Pictures

Certified GKH Gardening Expert
This appears to be a bacterial infection. Most commonly, this is from overwatering, or soil that does not have time to dry out between waterings.
You can try a bactericide, but plants such as these will often need to be restarted after the soil has had time to dry out and treatment is done.
These articles will help:
https://www.gardeningknowhow.com/garden-how-to/info/applying-bactericide-to-plants.htm
https://www.gardeningknowhow.com/edible/vegetables/squash/growing-spaghetti-squash.htm
https://www.gardeningknowhow.com/edible/vegetables/zucchini/growing-zucchini.htm