Learn when and how to water your herb plants for better growth, health, and flavor.
Use this in-depth guide to determine how often and how much water to give your herbs plants. We take a look at the different watering requirements for all types of herb plantings, inside, outside, in pots, smaller seedlings, and larger perennial groupings.
Table of Contents
Many herb plants are relatively drought-tolerant, but all require some water. Read on to learn when and how to water herbs of different types and ages.
Watering Requirements for Different Types of Herbs
Different herb plants thrive on different amounts of water. Many herbs, especially those native to the hot, dry climate of the Mediterranean, are quite drought-tolerant but struggle if overwatered.
Some herbs are more water-loving. Here are some lists and general guidelines to get you started:
Watering Moisture-Loving Herbs.
Herbs that will thrive best in somewhat moist soil include:
- Lemon balm
Ensure these plants get at least an inch of water every week from rain or watering. You may also want to plant them in somewhat rich soil which retains moisture longer. Mulching the soil will also help it hold moisture in.
Even these herbs don’t grow well in puddles. Don’t plant them in boggy ground, and make sure the soil drains well.
Watering Midrange Herbs
Herbs with moderate moisture requirements include:
These herbs tend to be described as wanting “moist, well-drained soil.” This may be best achieved by planting them where drainage is good and watering them often.
Watering Drought-Tolerant Herbs
Herbs that thrive in drier soil and may lose vigor, hardiness, or flavor if they are too moist include:
- Lemon verbena
- Savory (both summer and winter)
When you’re in doubt about whether to water or not, err on the side of letting these dry out. But don’t take this too far–every plant still needs some water in order to grow.
Rodale’s recommends one inch of water a week for these, as for other plants, but also suggests letting many of them get a little dry between waterings.
You may also want to plant these in fairly sandy soil, on high ground, or on slopes. All these environments promote quick drainage.
For more information on checking how fast your soil drains, see our article on The Best Location for Your Herb Garden.
When to Water Garden Herbs Outdoors
In general, most herb plants will grow well with about an inch of water every week. This can come from rain or watering.
Set a rain gauge out in your herb garden so you can tell how much rain your plants are getting. Make sure you don’t put it under plants that will block rain from entering it.
Plants from the moisture-loving list above will benefit from light watering whenever the soil feels dry around them. Plants from the drought-tolerant list should be allowed to dry out a bit between waterings.
The Best Time Of Day To Water Herbs
Water in the morning or the evening, not in the heat of the day. This way more of the moisture will soak into the soil instead of evaporating off.
With large established plants, you’ll usually want to get as much as possible of your water straight to the roots.
Fungus-susceptible herbs like lavender will do best if you don’t get their leaves, stems and flowers too wet. You can accomplish this by installing drip irrigation. Or you can take the sprayer off your hose or watering can and set the open nozzle right by the base of the plant you’re watering.
However, this approach doesn’t work for seeds or new seedlings–see below.
Your herbs’ water needs will be affected by several factors:
Herbs grown in sandy soil, which drain fast, will need more water than herbs grown in clayey soil or soil heavily amended with compost, which hold moisture longer.
Clay soil poses challenges of its own, as it can either become waterlogged or dry and harden. For more information on soil types and how to improve soil that drains too fast or too slowly, see our article on improving your soil.
Soil exposed to the sun dries out faster. You can retain moisture by spacing herb plants closely so that they shade the soil, or surrounding them with cooling mulch like leaves or straw.
Other factors that can influence the frequency of watering include:
- Plants grown in full sun will dry out faster than plants grown in the shade. (Many herbs grow best in full sun.)
- In the heat of summer, plants will dry out faster.
- Strong winds will also dry your soil and require extra watering.
Rodale’s Garden Problem Solver says that gardens with very rich soil, or mulched gardens watered by a drip irrigation system, may need only 1/2-3/4 of an inch weekly.
Sandy gardens, they say, may need two inches. Many Mediterranean herbs grow best in light sandy soil.
Watering Herbs After Transplanting
Newly transplanted herbs need to be well watered to help them overcome transplant shock and settle into their new location.
To encourage root growth, set transplants into soil that is moister than the soil inside the pot. Water regularly for the first week or so, especially if the weather is hot.
Watering in Seeds & Growing Seedlings
New-planted seeds and small growing seedlings (even of drought-tolerant herbs) should be kept moist but not soggy. This means more frequent, lighter waterings.
Use a sprinkling can or a “mist” or “gentle shower’ setting on your hose to avoid washing out seeds or small tender seedlings.
When to Water Herbs in Containers (Outdoors)
Herbs grown in outdoor containers may need to be watered more often than herbs grown directly in the soil. Their root systems are confined by their containers and can’t stretch down to access moister layers deep in the soil.
Also, the sun may warm the soil in their containers more than it warms the ground. Drought-tolerant herbs should still be allowed to dry out on the surface between waterings. Make sure that your containers drain properly so that you don’t drown the roots of your plants.
Watering Indoor Herbs
Herbs grown indoors may need less water than herbs grown in containers outside since they are not exposed to drying winds. However, on sunny days in spring and fall, plants grown in a sunny greenhouse may be substantially warmer than outside plants, and so may need more water.
Here in New York where the winters are cold, I water the plants in my “winter garden” on sunny mornings so that the soil isn’t staying soggy through the cold nights.
Maintenance—How to Know if You’re Doing Things Right
- Plants that aren’t getting enough water will wilt. Some plants, especially those with large tender leaves, will wilt a little in the heat of a sunny afternoon even when they’re basically fine. But if your plants look wilted in the morning, they are too dry.
- Overwatering can lead to root rots and fungal diseases. If puddles form and stay on the surface of your soil, it is too wet and you’re at risk of root rot. This probably indicates poor drainage as well as overwatering.
If all this sounds complicated, don’t worry. Your plants will let you know whether they’re getting too much, not enough, or just enough water. And it’s easy to adjust your watering program in either direction to get plants back to peak health.
Just pay attention to your plants and do more of what works.