Herbs are very simple to grow and can even be done in pots on the windowsill, but the biggest mistake gardeners make is thinking they can all be fertilised the same. Leafy herbs such as basil, mint or parsley will greatly benefit if you feed them a good amount of the nitrogen in late spring as it will help the plants grow quickly and improve their taste.

However, it should be noted that woody herbs such as rosemary, thyme and even lavender need to be fertilised very differently. Nitrogen is the nutrient responsible for foliage growth and if given to Mediterranean herbs it will dilute their flavour, make them weaker and make them more likely to become diseased. 

If you are growing leafy herbs then feed them once a month with a nitrogen-rich fertiliser or make your own with teabags or used up coffee grounds. 

However, if you are growing woody herbs like lavender, rosemary and thymem then you are better giving them a light feed only once in spring to help strengthen them.

Vladka Merva, a herbalist and founder of Simply Beyond Herbs, has shared a simple way to give woody herbs a boost if with crushed up eggshells. 

She said: “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 helps improve their health and it encourages root development so can help prevent common plant diseases like blossom end rot. 

It also helps makes the soil more alkaline, which herbs such as lavender and rosemary will love.

Eggshells are also naturally sharp will helps prevent many pests from crawling on herbs, which can be a big issue if you are growing them in your kitchen as insects often attracted to houseplants. 

Vladka Said: “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

If you are growing herbs in your garden then first wash your eggshells thoroughly as any leftover yolk can attract insects. 

Place the eggshells somewhere warm to completely dry out, and then crush them up with a rolling pin as it smaller pieces will decompose easier. Then, all you have to do is sprinkle the eggshells into the soil of your lavender, rosemary or thyme plants. 

However, if you are growing lavender, thyme or rosemary indoors then you can actually use the eggshells as a plant pot to grow your herbs. 

Use a sharp knife to carefully remove the upper pointed end of a egg so you have the bottom intact. Then wash them thoroughly as any yolk can encourage pests or mould. 

While the eggshell is still wet, use a small needle to prick a hole in the bottom of each eggshell. This is done so water can easily drain away from the herbs and does not build up in the soil. 

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

Then simply add a few seeds to each eggshell and write the name of the herb in permanent marker. Water once a day, place somewhere sunny and you should have a blooming herb garden in no time.