Don’t throw away those egg crate cartons, because you can use them as a seed-starting tray this spring! Depending on the type of carton you have, you can even cut apart the individual sections and plant them, as the carton will biodegrade. Be sure to poke small holes for drainage, and put the cartons on a tray or in a shallow pan to catch any residual water.
Supplies that you need to start your little seedlings:
- Cardboard egg carton
- Potting soil
- Coffee grounds
- Waterproof tray to place under egg carton
Make a half-and-half mixture of equal portions of soil and grounds. A soup bowl full of this mixture should be plenty for this project. If you aren’t a coffee drinker, don’t worry! You can always stop by your local coffee shop and ask for used grounds. They’re usually happy to give them away for free.
plant your seeds in the egg carton without cutting it apart, and you can also cut it apart after your seeds have sprouted, but I’ve found that doing it in the beginning helps to prevent your roots from getting tangled later. It also keeps you from accidentally crushing or breaking sprouts while trying to separate the cups later.
Fill your individual egg cups about half full with the soil/grounds mixture.
Be sure not to add too many seeds to each egg cup. Overcrowded seedlings will often die off. For larger plants like squash, I plant only one or two seeds per cup. For smaller plants like cilantro and parsley, I plant about four or five seeds per cup. Remember that not every single seed will actually sprout, but that sprouted seeds will need room to grow and soil resources for nutrients. Cover seeds with a fine layer of the soil mixture.
Place the water proof tray under the egg carton ( to help catch water drainage)
Pour water directly into the plastic plate rather than over the individual seed cups. The paper cups will soak up the water and keep your seeds moist. I maintain about a centimeter of water in the bottom of the plate at all times.
Be sure that your seed cups are in a place where they can get enough sun & watch your seeds sprout within 4-8 weeks!