Have you ever tried growing herbs in water? Whether you want to start new plants or grow a small herb garden in your kitchen, many herbs will take root and continue to grow with a little tap water and a warm window.
Does that sound too easy? Well, there are a few tricks to it. And some herbs do better than others.
But you don’t need a fancy setup or a lot of equipment to get started. You can get a good start with a plain container of water and a little time and attention.
In this article, we’ll take a look at the different ways you can grow herbs in water. Then we’ll go over the list of the herbs that are easiest to propagate and sprout roots.
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Can You Really Grow Herbs in Just Water?
Yes. You absolutely can. You can start new herb plants by taking cuttings from existing plants and putting them in a container of plain water. The herbs will sprout roots that will draw up water (and any available nutrients )to the cuttings to create new plants.
Water bottles work very well or any container with a smaller lip. This keeps the herb leaves from falling into the water. I also like to tie my herbs with a little twine as you can see in the photo above. This keeps them neat and tidy.
I also use this method also to keep my store-bought herbs fresh longer. And while it doesn’t work as well as when I take fresh cuttings from an existing plant. I’m often surprised by how long they last. I’ve even had grocery store herbs bloom when keeping them this way.
For long-term growth, you’ll need to put them in soil or else set up a hydroponic growing system with nutrient solutions and growing mediums.
How To Grow Herbs In Water – 2 Different Ways
You can multiply your plants quickly and easily by taking soft-stem cuttings and rooting them in water. Here’s how it works.
- Take stem cuttings between 4 and 6 inches long from healthy plants. If possible, choose fresh young stems without flower parts. If there are flowers, rub them off.
2. Remove leaves from the bottom half of your stem cutting. This will prevent the water from getting murky.
3. If you are rooting one of the trickier herbs (such as rosemary or lavender), you can use a rooting solution to help it along. Set your cutting in a container of rooting solution for several hours. Submerge the stripped part and keep the leaves out of the water.
4. Fill a container with tepid water. A clear glass container makes it easy to check on rooting. A dark pottery vase will retain solar heat and also shield roots from light.
5. Submerge the leafless part of the stem in water in your container. Keep the leaves above the waterline. Use a container that is narrow at the top, so they don’t accidentally fall in. I’ve used a champagne glass above which is a good size for just a few stems.
6. Place your container on a sunny windowsill or another warm, well-lit place.
7. Change the water every few days. Warmish/room temperature water is best for rooting—hot water can kill the plant, and cold water will slow down root development.
8. Wait for roots to emerge. You should begin to see white rootlets within a couple of weeks.
9. When roots are ½ “-2” long you can transplant your herbs into plant pots, either in soil or in a hydroponic growing medium.
10. You can also keep them in containers. Many will last for a few months. Some just a few weeks. Either way, it’s a convenient way to keep herbs at the ready in your kitchen for your next meal.
If you want to grow herbs indoors without soil over the long term, you’ll need a somewhat more complex hydroponic growing system.
In a hydroponic herb garden, you need to provide nutrients and a growing medium as well as water and light. There are different ways to set up such a system.
- You can attach plants to foam floats on the surface of a nutrient solution. This is the method used by kits like the Aerogarden.
- You can suspend plants in a nutrient solution in net pots filled with a soilless growing medium or substrate. This is the method you may see in a Ball jar hydroponic kit.
The beauty of these systems is that they are self-contained, so they provide all the needs of the plant within a small growing space. If you want to get started in hydroponic growing, check out our list of hydroponic kits for beginners for a few of our favorites.
List of Herbs That Will Root in Water
The following list is alphabetical, but some of the more challenging herbs appear early in it. Mint and thyme might be the easiest herbs for beginners to root.
Basil—Take cuttings early in the season, before the plants begin to bloom. Transplant into soil or another solid growing medium once roots are 1-2 inches long. Or leave them growing in water.
Basil can last for several months in just water as you can see from the photo below, they will develop quite large root systems.
Lavender—This can be slow to root. Dipping the cut end in rooting hormone before setting it in water can help it along. You can buy rooting hormone. You may also be able to make your own with willow water—see below.
Lemon balm—It may take up to a month for roots to appear on lemon balm. Transplant your cuttings into a solid growing medium once the roots are 1-2 inches long.
Marjoram—This is another slow rooter, requiring up to a month.
Mint—Mother Earth News says this is an easy plant on which to practice propagation. It may start to root within ten days. Better Homes and Gardens adds that it will keep growing in water alone for ‘quite a while.”
Oregano—Take cuttings from soft green new stems, not woody older stems.
Rosemary—As with oregano, take cuttings from fresh green stems. Rosemary can be slow to root; dipping the cut end in rooting hormone before setting it in water can help it along.
Sage—Take cuttings from new growth in spring. Change the water regularly since sage can be rot prone.
Stevia—This homegrown sweetener also appears on some lists of herbs that will root in water, but I haven’t found specific advice on how to grow it.
Thyme—Take cuttings in spring or early summer. Make your cut just below a node (the place leaves sprout from). Thyme will start rooting in 2 weeks.
DIY Rooting Hormone
Willow trees of all kinds contain a chemical called indolebutyric acid which helps speed and strengthen root development. Master Gardener Mark Bernskoetter recommends chopping willow branches into 3–6-inch pieces or else peeling off bark.
Pour a gallon of boiling water over two cups of chopped twigs or three cups of bark. Let this sit for a day before removing the wood or bark. Set hard-to-root plants like rosemary and lavender in this solution for several hours before setting them into plain water to grow. Easy-to-propagate plants like mint may not benefit from being dipped in willow water.
As you can see, there are many different ways to grow herbs in water. You can use this method to start new plants or keep a small supply of fresh herbs on your kitchen windowsill.
Try out this cool method of growing herbs the next time you have a few extra sprigs of thyme from the grocery store or take a cutting of your Rosemary plant. Experiment with different types of containers and different growing spots in your home. Make notes on what works best in your space and with your plants.
Growing herbs in water is an easy way to get started with hydroponic gardening on a small scale. And having a few fresh herbs growing in your kitchen can be a great reminder to incorporate them into your daily meals.