Best mulch for herbs | Basil, Parsley Rosemary + More

The best mulch for Mediterranean herbs is bark or mixed tree mulch because it is long lasting and improves the soil. The best mulch for soft herbs like basil, coriander and parsley is straw, hay or sugar cane mulch. These mulches break down quickly and hold moisture in the soil.

Best mulch for herbs

Herb typeBest Mulch
ThymeBark mulch or landscaping rock
RosemaryBark mulch or landscaping rock
SageBark mulch or landscaping rock
MarjoramBark mulch or landscaping rock
OreganoBark mulch or landscaping rock
BasilSugar cane mulch or straw
ParsleySugar cane mulch or straw
CorianderSugar cane mulch or straw
MintSugar cane mulch or straw

The best natural mulch for herbs

Natural materials are the best option to put around your herbs. If you have planted herbs in your vegetable garden, then use a soft mulch like straw, hay or sugar cane mulch. You can also use well aged compost around your herbs to add extra nitrogen for good leaf growth.

These mulches will break down over a season so are perfect for herbs grown annually. Parsley, coriander and basil work best when replanted each year. If you are growing herbs from seeds, then leave the soil without mulch until the plants grow 2-3 inches high. You can then move the mulch around the plant when it is larger.

Mulching Mediterranean herbs

Mediterranean herbs benefit from a longer lasting woody mulch like bark mulch or mixed tree mulch. A mixed tree mulch will contain small and large pieces from mulched tree branches. Green leaves and brown stems mix well to break down over time and add extra nutrients to the soil.

Use bark mulch around Mediterranean herbs like Thyme

Before laying bark mulch add a thin layer of aged cow manure or pelleted chicken manure. This adds a small amount of nitrogen back into the soil which will offset the small amount absorbed by the break down of the bark materials. When bacteria start to break down the bark mulch, nitrogen is taken up but later released. 

Check out this video for easy ways to mulch your herb garden.

Mulching basil

Basil is a soft herb and grows as an annual in most areas so choose a mulch that will break down over the same season. Basil will grow in the warmer months and is the perfect companion plant with tomatoes. Surround both with straw or sugar cane mulch.

Basil works well with straw or sugar cane mulch

At the end of the growing season when the weather starts to cool dig the sugar cane or straw mulch into the soil. By then the mulch will look darker and have broken down well. The added carbon from the mulch will prepare the soil for your next planting. You can use this area to grow snow peas, onions, Asian greens.

How to use mulch around herbs

The most important tip to remember when mulching around herbs is to keep the mulch away from the stem of the plant. If the mulch is up against the stem you run the risk of causing rot by keeping the moisture around the plant.

Apply the mulch 2-3 inches thick around the herbs. Whether you are using bark chips or straw, this is the thickness that will stop weeds from growing through and keep moisture in the soil.

How to use landscaping rocks as mulch for herbs

Mediterranean herbs like thyme, rosemary and sage all like dryer conditions so rock mulch helps with drainage. Rocks will also absorb and reflect heat from the sun keeping them warm. Landscaping rock mulch will match Mediterranean conditions where herbs originally grew in rocky outcrops or rocky soil.

The downsides of using rock mulch are that it is heavier and more difficult to move than bark much or straw. Herbs like rosemary will grow for years so rock much can be applied and left in the same place.

It is best not to use rock mulch underneath softer herbs like basil, coriander or chives. These are herbs which are grown best if replaced each year. This will be easier if the mulch is lighter and breaks down.

Mulch to avoid around herbs

Grass clippings

Don’t use grass clipping around herbs because it can carry weed or grass seeds and sprout around your herbs. Any weed seeds will compete with your herbs and can slow their growth. Grass clippings can also form a thick mat around the ground and grow mold in damp areas. The mold can look unattractive and form a barrier that can stop water from getting through to your plants.

Sawdust

Sawdust is best avoided when mulching plants because it forms a tight layer over the top of the soil and can affect the acidity in the soil. If you have extra sawdust it is best to mix it through your compost to break down first.

Using compost as mulch around herbs

If you have homemade compost or have bought some bags from your local garden center you can use this around your herbs. Compost mulch has the added benefit of adding extra nutrient to the soil as it rains.

For herbs that you have already planted, added compost to the top of the soil is like adding a slow release fertilizer. It also works to keep moisture in the soil. You can add a thinner layer of straw or bark mulch over the top of the compost.

Using worm castings as compost around herbs

To use worm castings around your herbs as mulch add a thin layer sprinkled on top of the root zone. Worm castings also work well as a mulch when mixed with regular compost first to add extra structure. Add this mix on top of the soil around herbs and it will add extra nutrients to the soil over time and fertilize your herbs.

Mix worm castings with compost or cover them with straw or bark mulch around herbs.

Mulching around herbs – Summary

Mulching around plants is a great way to keep moisture in the soil and save water. Choosing right kind of mulch will improve the soil for your plants and help your herbs to grow more leaves for you to use at home.

Long growing rosemary and thyme benefit from a longer lasting mulch like bark mulch. For annual herbs choose a shorter lasting mulch like sugar cane that breaks down quickly and adds nutrients to the soil. Avoid grass clippings and sawdust as these can absorb too much nitrogen from the soil and starve your plants.

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