Just like us, plants need calcium to grow up big and strong. Eggshells are an effective and inexpensive way to give your plants a calcium boost.
When your plants aren’t getting enough calcium you may see it with twisted leaves or black spots. On tomatoes, peppers, and squash fruit that starts rotting on the bottom, also known as blossom end rot, may also be a sign that your plants need more calcium (although sometimes this could also mean inconsistent watering).
And placing loosely crushed eggshells around the base of plants can also deter snails as they don’t like to crawl over the shells.
Eggshells are great to toss in your compost bin on a regular basis as is, but I definitely recommend preparing your eggshells using the following or similar method when you are adding it directly to your soil. This will dry the eggs and help get rid of bacteria, like salmonella, to make it safe for your soil and also allows you to store the shells longer.
Preparing Eggshells for the Garden:1 About two weeks before I plan to plant my spring garden, I start saving my eggshells whenever I use eggs for breakfast or in other recipes. Simply store a small plastic container in the refrigerator then pop the used shells in and close the lid until you collect a good handful of shells to prepare.
I saved about 3-4 dozen eggs this year for my spring garden. After planting 12 tomatoes and about 8 peppers I still have plenty left over to use in other parts of the garden.2 When you are almost ready to get your plants in the ground, take the eggshells out of the fridge and soak them in some water for 10 or so minutes. You can add a little bit of soap if you want (but see my note below about this).
I recommend placing a strainer inside a big bowl so it is easier to pull the shells out and strain out the water.3 Rinse the eggs thoroughly. If you used a little bit of soap, I recommend rinsing each shell individually as you don’t want the soap to sneak into your soil.
Let the shells dry on a towel while you start working on the next step.4 Preheat the oven to 200°F, and line a baking sheet with some parchment paper. Place the eggshells on the parchment paper in a single row. Make sure none of the shells are nesting inside each other.
I prefer to place the shells broken-side down on the baking sheet. You don’t necessarily have to lay out the eggs this way, but it will help everything to dry out quicker.
Bake the shells at 200°F for 20-30 minutes or until the shells are completely dry.5 Once the eggshells are done drying out in the oven and have cooled for a few minutes, they are ready to be grinded up to make it easier to apply in your garden. You can use a pestle & mortar, coffee grinder, or food processor.
I opted to use my food processor and processed the eggs in a few batches since there were so many. Just fill the processor, pulse a few times until it seemed like the shells are as crushed up as they will get, then dumped those out and run another batch until they are all done.6 Store the shells in an airtight container like a mason jar or plastic container if you aren’t using them right away.
I add crushed eggshells when I am planting tomatoes and peppers in to my garden, around plants that are prone to attract snails, and sometimes I work it in to my soil if I have some extra or think certain plants need a little calcium boost.
It seems like the eggshells would last for a long time if stored properly, but I say you might as well use them right away because it’s pretty easy to collect enough shells in a few weeks to do it all over again!
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