This is my version of the Winstrip seed starting tray. 2 of these fill a standard 1020 seed plant tray. Each print provides 25 - 44mm seed starting spots and measures 250mm x 250mm x 50mm. Print profile is provided for a A1 with .6 Nozzle. No supports are needed.

Winstrip trays are an alternative to soil blocking and provide all the air pruning benefits that soil blocking provides. Just fill your trays with your trays with your favorite potting mix, plant the seeds per the directions on the seed packet. Bottom water till top looks dark and moist. Repeat bottom watering in the same fashion once top starts to turn brown.

In a traditional plant pot the roots turn when it hits the plastic edge, this can lead to what is called root bound and can choke itself to death. With air pruning as soon as the roots hit the air, it dies and splits in multiple directions. Air pruned starts have more densely populated roots throughout the root ball instead of the outside. This helps lessen transplant shock and gets the plant to a healthier faster start as each split turn into its own root once transplanted.