Growing herbs in water indoors is an easy way to enjoy fresh flavor without a garden, large pots, or much equipment. With a sunny window, clean container, and a few healthy cuttings, many kitchen herbs can produce new roots within days or weeks.
Which Herbs Can Grow in Water
The easiest herbs to grow in water are soft-stemmed plants that readily produce roots from cuttings. Good choices include:
- Basil: Roots quickly in warm, bright conditions.
- Mint: Vigorous and forgiving, but keep it in its own container.
- Oregano: Can root from fresh stems and continue producing leaves.
- Thyme: Works well, although it may root more slowly than mint or basil.
- Rosemary: Can root in water, especially from young, flexible stems.
- Sage: Sometimes roots successfully, but tends to be slower and less reliable.
- Lemon balm: Roots readily and grows vigorously.
Green onions and scallions can also regrow in a shallow glass of water. Their roots are already present, so they are particularly simple for beginners.
Water-grown herbs can remain healthy for weeks or months, but most will not grow as vigorously in plain water as they would in nutrient-rich soil. Water is excellent for rooting cuttings and harvesting small amounts of leaves. For long-term, larger plants, you may eventually need to move them into soil or a hydroponic growing system.
How to Start Herbs From Cuttings
Start with a fresh, healthy stem. Avoid stems with yellow leaves, black spots, mushy sections, or signs of insects.
Follow these steps:
- Cut a 4- to 6-inch stem just below a leaf node. A node is the point where leaves emerge from the stem; this is where new roots are most likely to develop.
- Remove the lower leaves, leaving two or three sets of leaves at the top. No leaves should sit below the waterline.
- Place the cutting in water immediately so the cut end does not dry out.
- Set the container in bright, indirect light. Avoid intense afternoon sun at first, which can overheat the water and cause wilting.
- Check for roots after 7 to 14 days. Basil and mint may root sooner, while woody herbs such as rosemary can take several weeks.
- Wait for several healthy roots before harvesting heavily or transplanting. Roots around 1 to 2 inches long are a useful starting point.
Take several cuttings rather than relying on one. Not every cutting will root, particularly when stems are old, woody, or damaged.
Best Containers and Water for Indoor Herbs
Choose a clean container that supports the stem without crushing it. Small glasses, jars, narrow vases, and propagation tubes can all work. A narrow opening is helpful because it keeps the cutting upright, but the opening should not be so tight that it traps moisture around the stem.
Use these guidelines:
- Wash the container with hot, soapy water before adding a cutting.
- Use cool or room-temperature tap water.
- If your tap water has a strong chlorine smell, let it stand uncovered for a few hours before use, or use filtered water.
- Keep the water level below the leaves. Only the bare stem and developing roots should be submerged.
- Avoid filling the container to the top, since stagnant, waterlogged stems are more likely to rot.
- Use an opaque container or wrap a clear jar if algae becomes a recurring problem.
Plain water is usually enough while a cutting is forming roots. Once roots are established, a very dilute, balanced liquid fertilizer can support longer-term growth, but follow the product label and avoid strong concentrations. Excess fertilizer can damage young roots and encourage algae.
Where to Place a Water-Grown Herb
Place herbs near a bright window where they receive about 4 to 6 hours of light daily. An east- or south-facing window often works well, although a south-facing window may provide intense heat during summer.
Look for a location with:
- Bright light without scorching midday sun
- Temperatures roughly between 60°F and 75°F
- Protection from cold drafts and heating vents
- Enough space for leaves to spread without touching dirty surfaces
Rotate the container every few days so the plant grows evenly. If stems become long, thin, and pale, the herb probably needs more light. A small grow light can help during winter or in a dark room. Keep the light a few inches above the foliage and follow the manufacturer’s recommended schedule.
Do not place water-grown herbs directly against cold glass in winter. Chilled water and leaves can slow growth and increase stress.
How Often to Change the Water
Change the water every 3 to 7 days, or sooner if it becomes cloudy, smells unpleasant, or contains debris. Fresh water supplies oxygen and reduces the buildup of bacteria, plant residue, and fertilizer salts.
When changing the water:
- Remove the cutting carefully, supporting the roots with your fingers.
- Rinse the roots gently under room-temperature water if they feel slimy.
- Empty and wash the container.
- Refill it with fresh water at a similar level.
- Return the cutting and check that no leaves are submerged.
During hot weather or when the container sits in strong light, water may evaporate quickly. Top it up between changes, but do not rely only on topping up for long periods. The container still needs regular emptying and cleaning.
How to Prevent Rot, Algae, and Weak Growth
Most problems come from too much moisture around the stem, insufficient light, or dirty water. Prevention is easier than recovery.
To reduce rot:
- Keep every leaf above the waterline.
- Remove any soft, brown, or black section immediately.
- Use healthy cuttings with clean cuts.
- Change cloudy water promptly.
- Do not overcrowd several stems in one small container.
To limit algae, block light from reaching the water with an opaque container or sleeve. Algae is more likely when a clear jar sits in strong light and receives fertilizer. A small amount may not kill the herb, but heavy algae can compete for oxygen and make the roots difficult to inspect.
Weak, pale growth usually indicates low light. Move the herb closer to a bright window or add a grow light. If the plant has many leaves but very small roots, give it more time before taking cuttings or harvesting. Once roots are established, trim the growing tips occasionally to encourage branching rather than one tall, fragile stem.
When to Move Water-Grown Herbs Into Soil
Move an herb into soil when it has several firm, pale roots about 1 to 2 inches long, or when growth has slowed despite good light and clean water. Basil, mint, and oregano often adapt well. Woody herbs may need extra care because water-grown roots are delicate and different from roots formed in soil.
Use a small pot with drainage holes and a loose, well-draining potting mix. Avoid placing a small cutting directly into a very large pot, which can stay wet for too long.
To transplant:
- Moisten the potting mix lightly.
- Make a hole deep enough to spread the roots without bending them sharply.
- Place the cutting in the hole and cover the roots with mix.
- Water gently until the soil is evenly moist, not saturated.
- Keep the plant in bright, indirect light for several days.
- Gradually return it to stronger light as it adjusts.
The plant may wilt briefly after transplanting. Keep the soil lightly moist during the first week, then allow the top inch to dry before watering again. Once established, harvest no more than one-third of the plant at a time.
Frequently Asked Questions
Can herbs live in water permanently?
Some herbs can survive in water for a long time, especially mint and basil, but plain water does not provide every nutrient needed for strong, sustained growth. For a fuller, healthier plant, use a suitable hydroponic nutrient at the recommended dilution or transplant the herb into soil.
Why are my herb’s roots turning brown?
Brown roots may result from natural aging, dirty water, too much light, or root rot. Healthy roots are usually firm and light-colored. Remove soft or slimy roots, wash the container, trim damaged tissue with clean scissors, and place the cutting in fresh water with better light and airflow.
Can I grow grocery-store herb cuttings in water?
Yes, provided the stems are fresh and healthy. Remove wilted leaves and any damaged ends, then recut the stems below a node. Herbs that have been sitting in a refrigerated package for a long time may root less successfully, so start with several cuttings.