Egg shells and composting: tips

Egg shells improve soil fertility. They help plants grow strong and healthy by releasing:

• calcium that strengthen the cell walls of plants

• magnesium aids the process of photosynthesis

• potassium reduces water loss and wilting

• prevent blossom end rot (calcium deficiency) causing the flowering end of a fruiting plant to rot

• helps worms digest food

• raises the soil pH (less acidic)

How to compost egg shells

Like many of us, I used to throw my egg shells into the compost bins but found they remained intact and didn’t break down for a very long time.

Curious about how to improve this, I read a Gardening Australia article with advice that really works.

Instructions:

• Dry egg shells in a warm oven: I place them in the oven after I have finished cooking and turned the oven off, leaving them in the oven until it is cold.

• Crush shells to a fine powder either with a mortar and pestle or grind them in a coffee grinder… much easier!

• Add the ground egg shells to your compost

Tips and tricks

• Handle old egg shells with care as there is a small risk of salmonella contamination

• Check for egg remains in the shells as they can attract pests. I throw these in the bin

• Remember that some plants prefer acidic soil (e.g., blueberries, magnolia), and won’t appreciate egg shells in the compost. Before adding compost with crushed egg shells, test your pH levels first