East Sac Edible

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Composting Eggshells

Eggshells are always a great addition to your compost because they provide essential grit for worm’s digestive systems and the calcium in eggshells can help neutralize acidic conditions in your compost pile. I have always just thrown in my eggshells along with everything else but they always take so long to decompose. This is nine month old compost and you can see that there is still a large remnant of eggshell in the compost. DSC_2628I have always wondered how the worms actually get the benefit of the eggshells if they are often still in the exact same shape as when I threw them into the compost months ago. I know the worms are not taking huge bites out of these shells (haha, worms don’t have teeth). Some gardeners don’t like the look of eggshells in their compost and wont include them but I don’t really mind the look. However, I was thinking that ground up eggshells would be easier for the worms, especially the worms in my worm bin, to process. I started separating eggshells from my kitchen compost bin, slightly rinsing them, letting them dry and putting them in a separate container. When I had enough I lined them on a cookie sheet.

DSC_2610 DSC_2612The next time I had the oven on for tomato sauce I threw in the pan of eggshells too. I wasn’t so concerned about the temperature but just wanted to give them a while in an oven. So the eggshells sat in a 350° oven for about an hour. Then they went into my food processor for a quick whirl.

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Eggshell smoke puffed out. DSC_2623 DSC_2624


I was much happier with the consistency of the eggshells using this technique. Previously, I had tried blitzing some eggshells in a blender but without putting them in the oven and I wasn’t able to get as fine of a powder as I was by baking them first.

I don’t think I will use this technique all time but will definitely use it from time to time to add to my worm bin. I have noticed that halved eggshells in the compost provides perfect pockets for pill bugs, worms, and other little insects to set up camp in the compost pile mainly because eggshells don’t tend to break even with the weight of the compost material on top of them. Come to think of it, when I am in the kitchen using eggs I always think of how fragile the eggs are but those same shells are surprisingly strong in the compost! I have always noticed when I turn my compost lots of little insects coming out of the safe pockets of the eggshells. There are definitely benefits to the lazy-woman’s approach to adding eggshells to the compost!

I think I will also use the oven-baked eggshells next year to put in the bottom of my tomato holes (usually I just throw in a few whole shells) but maybe the plant will be able to utilize the calcium faster if it is crushed up. Something new to try!

I do hope the oven-baked eggshells will keep my worms happy!