What the heck was this? Spider eggs?

Mom was cleaning out her half barrels today, one was full of coleus and the other was full of zinnias (mostly dead). She tipped them out and was breaking up the roots, and found little yellow-gold orbs, like beads, smaller than 1/4" in the root mass of one or the other. What the heck was that stuff?? Could they have been eggs? What kind?

It might have been time release fertilizer pellets from the commercially potted plants. The shells don’t always desolve.

That sounds right. Mom was so insistent they were ‘spider eggs’, but I thought later, why would spiders lay eggs underground? Thanks for pointing out the logical.

Sounds like Osmocote-

Scroll down about 2/3 for a picture of it in soil.

Nitrogen fixers (peas, lentils. Alder, clover) grow little nodules on their roots for symbiotic nitrogen fixing bacteria.