Styrofoam peanuts help to reduce the amount of soil you need for planting. The Styrofoam does not absorb water; it helps to take up space in the pot to make it lighter and easier to move. Styrofoam peanuts will save you money because you will not have to pay for excess soil that you will not use. The packing peanuts help the water to drain, which prevents water buildup that may encourage root rot.
Place the peanuts in the bottom of a plant pot. Fill the pot 1/3 full with the styrofoam.
Fill the pot with soil leaving 1 inch of head space at the top. If you need to transplant a larger plant, then add 2 to 3 inches of soil over the Styrofoam peanuts, add the plant and then fill the pot with the rest of the soil.
Put the seeds into the soil. If you are planting a starter plant instead of seeds, make a hole in the soil large enough for the roots and place the plant into this hole. Fill the hole with the soil around the plant's roots.