Moisten the cotton ball thoroughly without saturating it. Hold it over the sink or put it inside a colander if excess water drips from it. Do not squeeze the cotton ball.
Place the cotton ball inside a flat or another container. A plastic snack-size bag is also an option. If water released from the cotton accumulates inside the container, turn it over the sink to empty it.
Place the seed on the moist cotton ball. If the seeds are small and hard to handle, place several on a plate and dab them lightly with the cotton. The seeds will stick to the wet surface. Put the seeded cotton ball back in the container.
Cover the flat with a lid or a piece of plastic wrap, or seal the plastic bag. Open the container once the seeds sprout.
Fill a planter with potting mix. Transplant the seedling to the pot without removing it from the cotton ball.