Gardeners urged to fertilise rosemary, thyme and lavender with one natural item

are surprisingly easy to grow and can even thrive in pots on your windowsill, but the common blunder among is treating them all the same when it comes to fertilisation. Leafy herbs like basil, mint, or will flourish if you give them a hefty dose of nitrogen in late spring, which bolsters their growth and enhances their flavour.

Yet, take note that woody herbs such as rosemary, thyme, and lavender demand a distinct approach to fertilisation. Nitrogen spurs on leaf growth, but for Mediterranean herbs, it can weaken their flavour, make the plants more susceptible to disease, and generally diminish their hardiness.

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For those cultivating leafy herbs, a monthly feed with a nitrogen-rich fertiliser is recommended, or you could whip up your own using spent tea bags or coffee grounds. On the other hand, if you're tending to woody herbs like lavender, rosemary, and thyme, they'll fare better with just a light feeding once in spring to bolster their strength.

Herbalist and founder of Simply Beyond Herbs, Vladka Merva, offers a nifty tip for giving woody herbs a leg-up using crushed eggshells, reports . She advises: "Eggshells are a great source of calcium that seeps into the soil as you water it. Calcium is important for plant growth and its nutrition as well as for the soil. It helps to maintain chemical balance in the soil and improves water penetration."

Feeding woody herbs calcium can boost their health and encourage root development, which may help ward off common plant diseases like blossom end rot. It also makes the soil more alkaline, a condition that herbs such as lavender and rosemary thrive in.

Eggshells, being naturally sharp, can deter many pests from crawling on herbs, an advantage especially if you're cultivating them indoors where insects are often drawn to houseplants. Vladka stated: "Crushed eggshells serve as pest control. Slugs, cutworms or other insects are put off by the crashed pieces of eggshells and rather leave."

How to use eggshells to give woody herbs a boost

For garden-grown herbs, start by thoroughly washing your eggshells to remove any residual yolk that could attract insects. Allow the eggshells to dry out completely in a warm place, then crush them with a rolling pin for easier decomposition. Simply sprinkle the crushed eggshells into the soil around your lavender, rosemary, or thyme plants. If you're growing lavender, thyme, or rosemary indoors, you can repurpose eggshells as quaint little plant pots.

Carefully cut the top pointed end of an egg with a sharp knife, keeping the bottom intact. Wash the shells well to prevent pests or mould before using them to nurture your herbs.

While the eggshell is still damp, use a small needle to pierce a hole in the bottom of each shell. This allows water to drain away from the herbs and prevents it from accumulating in the soil.

Use a tablespoon to fill each eggshell with soil, leaving a one centimetre gap at the top. Most garden centres will sell herb-specific soil, but for woody herbs, you'll need a light, sandy and slightly alkaline one.

Then simply pop a few seeds into each eggshell and label the herb with a permanent marker. Water once daily, place in a sunny spot and you should have a flourishing herb garden before you know it.