Drill holes about 2 inches apart on either side of plastic container to accommodate dowels.

Cut Plexiglas with a utility knife to fit in container, as illustrated (or have it cut at hardware store).

Wash fabric interfacing (to remove the flame retardant which is toxic to plants), then cut it the same size as your Plexiglas slants.

Make a "sandwich" to lean against each dowel by placing a moistened square of interfacing between two pieces of Plexiglas. Wrap the sandwich side to side with black plastic to prevent light from reaching roots.

Use clothespins to hold the sandwich together and to help maintain it at about a 45-degree angle in the container to maximize absorption of the solution.

Start seeds (lettuce, alfalfa, beans, etc.) by placing them between the interfacing and the Plexiglas, about 1/4 inch below the top edge. (You can also start seeds in moist perlite, then gently clean the roots and transplant them to the slants.)

Fill the container with 2 inches of nutrient solution with a pH between 5.8 and 6.5. Keep the level of the solution constant, and replace it with fresh solution every 2 weeks.

You may want to cover the open solution with black plastic to reduce light and keep down algal growth. If you do have a lot of algae, remove slants and clean out the container with a dilute bleach solution before putting in your next batch of nutrients.