A herbalist recommends adding a common food scrap to herb garden soil to help give rosemary, thyme and lavender a boost this summer. Woody herbs such as these require a different approach to fertilisation compared to leafy herbs like basil and mint.
Why Woody Herbs Need Different Care
Leafy herbs thrive with nitrogen-rich fertilisers in late spring and early summer, which accelerates growth and enhances flavour. However, applying nitrogen to Mediterranean woody herbs can weaken their taste and make plants more fragile and susceptible to disease. Instead, these herbs benefit from a light feed in spring to fortify them.
Eggshells: A Natural Fertiliser
Herbalist Vladka Merva, founder of Simply Beyond Herbs, suggests using crushed eggshells. She explains: "Eggshells are a great source of calcium that seeps into the soil as you water it. Calcium is important for plant growth and nutrition as well as for the soil. It helps maintain chemical balance and improves water penetration."
Supplementing woody herbs with calcium bolsters vitality, promotes root growth, and safeguards against issues like blossom end rot. It also increases soil alkalinity, which is beneficial for lavender and rosemary.
Pest Control Benefits
The rough texture of crushed eggshells acts as a barrier against pests. Merva notes: "Crushed eggshells serve as pest control. Slugs, cutworms or other insects are put off by the crushed pieces and rather leave."
How to Use Eggshells
First, allow eggshells to dry completely in a warm spot, then crush them with a rolling pin to speed up decomposition. Scatter the crushed shells around your lavender, rosemary or thyme plants.
For indoor herbs, eggshells can be transformed into miniature plant containers. Carefully remove the top of an egg using a sharp knife, keeping the base intact. Rinse thoroughly to eliminate any remaining yolk, which could draw pests or mould. While still damp, pierce a small hole at the bottom of each shell with a needle for drainage.
Fill each eggshell with soil, leaving a one-centimetre gap at the top. Use a light, sandy, mildly alkaline soil suitable for woody herbs. Sprinkle seeds into each shell, label with a permanent marker, water daily, and place in a bright sunny spot. Soon you will have a flourishing herb garden.
