Nursery flats hold the paper chain pots during seeding and germination. The flats give structure to the paper chain pots while providing drainage via bottom holes. These flats are a REQUIRED component of the paper pot system.
The flats can also be dual purposed used as microgreen flats. This may be a better long term solution for someone who is going through a lot of thinner walled germination flats.
Flats are sold in boxes of 10, so it’s 10 flats for $50