Because the eggshells are biodegradable, they make an ideal pot for seed starters. When the time comes, you can plant the seedlings in ground without removing the shells. They will break down and will be a good source of calcium for the future plant. The shell is so small, so add more crushed eggshells to the whole before planting. By crushing the shells, they will break down quicker.
How to use the shells as pots?
1. Use the deepest shell halves.
2. As any other pots, it is recommended sterilise them before use. Sterilize the shells by boiling them or by placing them in a hot oven for 30 minutes.
3. After the shells are cooled down, you will need to make hols for water drainage with an awl, needle or pin (anything long and sharp, really).
4. Fill the eggshell with moist potting soil using a small spoon. If the potting soil is dry, it can be humidified with water from a spray bottle before filling the eggshells.
5. Plant your seeds according to directions. The seed package will tell you how deep to plant the seeds, as this depends upon the species.
6. Place your shells on egg cartons. The carton provides a stable base with room for drainage, is recycled and looks cute. Alternatively, you can get miniature clay pots or use eggcups to display the planters.
7. Keep them moist, warm and provide appropriate light.
8. When sprouts appear and plants grow too big for their shells, plant them—egg and all—right into the soil or in bigger pot. The shell will eventually biodegrade and the roots will grow out of the shell.
If you want quick results, try beans or cucumbers – they usually sprout in a few days. For bonus points, use seeds that you saved from last year’s crop instead of buying seeds.