Gather a box of recycled paper (see note 1 for tips on paper selection). Shred, cut, or tear the paper into small pieces.
Place the paper pieces into a large bin and add enough warm water to submerge all the paper pieces. Soak the paper overnight.
Use a blender or food processor to blend the soaked paper into a pulp. You may need to blend them in batches. I blended each batch on high speed for 1 minute. Fill a large bin ⅓ full with water. Add about 3 cups of the paper pulp into the bin, stir to mix well. (The amount of pulp you add to the water will determine the thickness of the paper. You can experiment with the first few pieces of paper you make, and adjust the amount of pulp in the bin.) If desired, add food coloring to the mixture for a customized paper color.
Angle the frame at 45 degrees and insert it into the bottom of the container from one edge. Once the frame is completely immersed, gently shake it from side to side to ensure the pulp on top of the screen distributes evenly. Gently lift the screen up, hold the frame over the bin to drain excess water.
Flip the frame upside down (with the paper side facing down) on top of a towel. You can use some old bath towels or kitchen towels. I used a cotton table runner folded into three layers for increased thickness, allowing it to absorb water from the paper sheet more efficiently.
Add 1 cup of the paper pulp into the bin, stir to mix well. Repeat the earlier steps with another frame, allowing you to have two sheets of paper drying on the towel simultaneously.
Press a microfiber towel (I found it could absorb water better than a sponge) or a sponge on the top surface of the frames to absorb as much water as possible from the paper sheets. Wring out the towel or sponge as needed, and continue pressing until no more water can be absorbed from the paper sheets. Gently lift up the frames. If the paper sheet breaks, you may have made it too thin or not pressed out enough water. Gather the teared paper sheet and dissolve it in the water bin to try again until you get a perfect paper sheet.
Sprinkle seeds over one sheet of paper, gently remove the other sheet of paper from the towel, and place it over the seeded paper, allowing them to overlap. Optionally, add dried flowers, herbs, or glitter on top for decoration. Position the frame on the overlapped paper sheets, and utilize a towel or sponge to press the two sheets of paper together.
Lift up the frame, and use your fingers to firmly press the edges of the paper sheets to ensure they adhere together. Carefully lift the paper sheet from the towel and stick it to a window with direct sunlight or near a heating vent.
Repeat the procedure with the remaining pulp. Allow the paper to dry on the window overnight until they are completely dry.
Gently remove the paper from the window. Fold them into halves for making birthday or holiday cards.