Plant milkweed in your yard. You’ll get dozens of Monarchs, and they’ll reproduce with their pretty green black and white caterpillars everywhere.
Milkweed likes a lot of water, but is otherwise very simple. Can survive a couple weeks without water if you forget, likes both sun and shade, likes both rich and dried out powdery soil.
California’s monarch population is down 95% since the 1980’s.
This $20 project will make your yard nicer and help save them.
I suggest buying two or three mature plants from a garden center for $6-10 each, then planting the seeds as they produce them. If you just start by buying seeds you’ll have to wait too long and might not plant them correctly.
.
