Cardboard plants are fern-like landscaping plants that can add a lush, tropical feel to any yard or garden. They are also well suited to pot and indoor growing. They don't usually flower, but produce seeds in their pod-like fruit. New cardboard plants can be propagated from these seeds.
Drying Cardboard Plant Seeds
Harvest cardboard plant fruit to harvest the seeds. Wait until the pod has split open for easy access to the seeds. Spread the fruit, and use a spoon to scoop the seeds out into a strainer. Run water through the strainer to clean the seeds as much as possible.
Put the seeds into a container that has a lid, and fill the container with water. Put the lid on loosely, and allow the container to sit in the sun for two days. After two days have passed, open the container and pour out the water, which will now contain plant matter, excess leaves and any seeds that weren't viable.
Rinse the seeds with water again. Fill the container with water and rotate the container to move the water through the seeds. Dump the water to dump any remaining plant matter.
Pour the seeds out onto coffee filters and set the filters in a sunny spot. Leave the seeds for several days, until they're well dried. Protect the seeds from any wind or birds at this time.
Planting Cardboard Plant Seeds
Start your cardboard plant seeds in pots, to allow them to sprout and establish before being exposed to outdoor environments. Fill pots with a mixture of sand and potting soil (equal parts). Once they're established, cardboard plants will require good drainage with very little nutrition, and can be grown in sand alone. During sprouting, however, support them with a good potting soil.
Push the seeds into the soil mixture until they're fully covered. Water them sparingly; cardboard plants don't require much water, even as seeds.
Place the pots in the sun until the new cardboard plants sprout. Water them only when the soil has dried out. Once the plants have sprouted, they can be maintained in full sun or moved to partial shade.
Transplant the new cardboard plants to an outdoor setting, if you choose. Cardboard plants are viable in the garden, yard or border plant boxes with full to partial sun. Prepare your soil by turning up the top 6 inches of the garden soil and mixing it with sand. You should end with 30 percent garden soil and 70 percent sand, to ensure a quick-draining environment for the cardboard plant.
Dig a hole in the soil that is roughly the size of the pot in which you've grown your cardboard plant. Gently grasp the cardboard plant at its base, and pull it from the pot. Transfer as much soil as you can with the roots, and be careful not to damage the plant as you pull it out.
Place the plant in its new site, and use your hands to pack your planting soil around its base. Water until the soil is moist but not soaked.