Rock tumbler for cleaning, scarifying, and processing seed.

Here’s the original NCRS paper on using a rock tumbler to increase germination success.

https://www.nrcs.usda.gov/plantmaterials/nmpmcrj5935.pdf

Difficult seeds are so much easier with this. This is especially useful if your local ecology evolved with periodic flooding events.

Parsley seed consistently germinates in 24-48 hours after an overnight tumble in water with sharp sand. It took 3-4 weeks without tumbling.

Tumbling with dry sand for shorter periods of time cleans wild collected seeds without damaging them.

This is the only way I’ve been able to reliably germinate sand verbena and New Mexico Locust.