My vegetable and flower soil looks like it has the measles. I have mixed the soil with eggshells. The eggshells have a lot of nutrients that the plants need. Your eggshells are recycled and you have cheap food for the soil. The calcium from eggshells in garden soil moderates soil acidity while providing nutrients to plants.
I gathered up a bunch of eggshells from breakfast and baking. It doesn’t take long to gather a couple of dozen I rinse them in cold water and put them on a cookie sheet in the oven. You then sterilize them in a 200°F (93°C) oven for 30 minutes. As you all know eggs are known carriers of salmonella, which is why if you find a cracked one in the box throw it away. Never use eggs that are cracked. I always wash the eggs nearest the cracked one just in case.
You can then pulverize the dried eggshells using a mortar and pestle, or you can put in brown paper bag or a large plastic bag, close the top and roll a rolling pin over it. Stored in an airtight container, crushed eggshells will probably last forever.
I am sure you have heard of people putting eggshells in their coffee I have read that putting a dried, crushed eggshell along with the coffee grounds would help the flavor, but did putting eggshells in the coffee make it better? I don’t know for sure but eggshells are made up of primarily of calcium, which readily leaches into warm, acidic liquids like coffee, which has a pH between 4 and 5. Like a low dose of lime, the eggshells probably raised the pH slightly and mellowed its flavor. They also probably enriched the coffee with dietary calcium.
Yet eggshells are quite useful in adding calcium to homemade fertilizers, or you can simply make calcium water by steeping dried eggshells in water for a couple of days, and then using the strained water for your plants, including houseplants.
I haven’t tried the egg water, since I just put crushed eggshell in the potting soil and mix it. My plants look pretty good and it’s a cheap fertilizer. So try giving your soil some extra nutrients and see if your garden and houseplants look better.