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How Much & How Often to Water Rosemary? Seasons, Frequency, & FAQ

rosemary herbs in garden

Rosemary is a perennial herb popularly grown in the home garden for culinary purposes. Its provenance can be traced to the Mediterranean region, meaning it can thrive in hot climates with minimal care. The herb also requires minimum maintenance practices in terms of watering and keeping it healthy. This makes rosemary ideal for beginners.

Fortunately, we have researched and compiled everything you need to know about the proper way of caring for rosemary plants. In this article, we will discuss how much water and how often you should water your plants during the different seasons. Keep reading to learn more.

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How Much Water Does Rosemary Need?

arp rosemary
Image By: Manfred Ruckszio, Shutterstock

Despite being a durable plant that is tolerant to drought, rosemary plants need water to survive. Generally, rosemary plants need watering every week during summer and for two weeks in fall and spring. You should give the plant at least 7.6 liters of water for smaller plants and about 13.8 liters for mature rosemary plants.

This translates to at least a gallon of water for smaller plants, while larger mature plants require about 2 gallons of water every time. When watering, it is best to drench the soil around the base of the plant while ensuring it doesn’t pool on the soil and drains away. Since the plant is native to the Mediterranean region, it doesn’t do well in water-logged soils and always requires good drainage.

Loosely compacted soil allows for small air pockets to form, which are important for the healthy growth of the plant. Water retaining sticky soil such as clay is harder to grow rosemary plants in because it limits access of the roots to the air pockets in the soil.

If you have grown your rosemary plant in a container, always wait until excess water drains out of the soil from drainage holes at the bottom before adding any more. This is usually an indication that the soil is sufficiently moistened and is available for the roots of the plant.

You should be careful how much water you give your rosemary plants because watering too often will cause the leaves to brown and rot the roots, while not watering enough will cause the plant to wither and die.

How Often to Water a Rosemary Plant

The frequency at which you water your rosemary plant will depend on:

  • The region
  • Season
  • The position of the plant
  • Whether you have planted it on the ground or in a pot

If the plant is planted in pots outdoors, it will require the same watering schedule as plants growing indoors. The difference is brought on by temperature fluctuations.

During the hot summer days, you should water plants grown in the garden at least once a week. Potted rosemary plants grown in direct sunlight require watering every couple of days. This scheduling is vital if it hasn’t rained for an entire week. Yet, if it has rained for a day or two, your rosemary plants will be sufficiently hydrated and will not need any more water for a week or two.

The best way to know whether your plants need water is to inspect the top 1-inch layer of soil using a wooden ruler, a finger, or a moisture meter. If the soil is dry and crumby, it’s probably a good time to water your plant. The pot should also be light when lifted. However, if the soil is slightly damp to the touch and sticks on your finger, it’s best to wait for a couple more days before watering. 

benenden blue rosemary
Image By: nnattalli, Shutterstock

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Watering Rosemary Plants Grown on the Ground in Different Seasons

If you prefer growing your rosemary plants in your garden, watering will be influenced by the weather. Obviously, when rainfall is minimal in summer, your plants will require frequent watering. However, if you live in an area that experiences heavy humidity, the plants will be able to draw the much-needed moisture from the air.

Below are some estimates of how much and how often to water your rosemary growing on the ground for different seasons.

  • Summer: If your rosemary plant is growing outside in your garden, in the summer it receives maximum exposure to sunlight. Therefore, the plant needs water at least once a week. However, if it rains a week after watering, you don’t necessarily need to give it any additional water. Moreover, if your region experiences cloudy weather but does not rain, only water your plants every 10 to 14 days with the same amount of water as mentioned above.
  • Spring: During the spring, your rosemary plant will grow more vigorously as the climate gets warmer. This is also the season that gardeners add fertilizer to boost plant growth. Fortunately, the sun is never too hot in the spring so the plants don’t experience too much evaporation that dehydrates them. Your plants will need watering after every two weeks. Again, if it rains during the two weeks, you won’t need to water the plant, especially if the top soil layer is damp.
  • Fall: During the fall, the weather begins to cool down and you might experience frequent rainfall. In this season you also must water your plants once every two weeks. Your rosemary plants will require at least two gallons of water, which will depend on the plant growth level. If it rains at least once every week, there is no need to give your rosemary plants any additional water.
common rosemary
Image Credit: Veera, Shutterstock

Watering Rosemary Plants Grown in Containers in Different Seasons

Potted plants will need more frequent watering. The soil in the container will dry up faster and the plants lack enough space to seek out moisture. Like plants grown in the ground, watering will vary with the season and will depend on whether plants are grown indoors or outdoors.

Potted Plants Growing Outdoors

  • Summer: Potted rosemary plants growing outdoors will require water at least once or twice a week. However, if temperatures are soaring high and the plants are exposed to the full sun glare for most of the day, you might need to water your rosemary daily. Generally, water your pots until excess water drains out of the drainage hole to ensure all the soil is sufficiently wet.
  • Spring: As earlier mentioned, spring is the season when most plants experience a significant growth spurt. Therefore, your rosemary will need regular watering to support its development. Water it every ten days. However, this will depend on ambient temperature and how fast the soil dries up.
  • Fall: Once the summer heat simmers down, plants grown in a pot will require less water. Reduce the watering schedule to at least once every ten days. However, you should monitor your soil’s moisture content if your area experiences an unexpected heat wave.
potted rosemary in the kitchen
Image Credit: monicore, Pixabay

Potted Plants Growing Indoors

  • Summer: When you grow your rosemary plants indoors, you limit their exposure to dry winds and direct sunlight. Therefore, they will need watering only once a week. When determining the moisture content, you can give your plants less water because chances are high that the bottom half of the pot will not have completely dried out. After all, the plant is not exposed to direct light.
  • Spring: Even if the plant is potted and positioned indoors, it will experience new growth in the spring. So, it will need watering after every ten days. Just make sure the top one inch of soil is dry. In spring, half a gallon of water will suffice.
  • Fall: By growing your plants indoors, you limit their exposure to weathering elements. However, your plants will need at least half a gallon of water every ten days.

Watering Requirements in Winter

During winter, rosemary plants slow down their growth and will not need any additional watering¹ unless the rain doesn’t fall in a long time. If you live in an area with frosty and snowy winters and your plants are growing outdoors, they will not need additional water.

Even potted plants will have enough water to sustain them through the cold weather. If the plant cannot survive the harsh winter conditions outside, bring it indoors and you should only give it half a gallon of water once every 20 days.

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While rosemary plants may be native to the Mediterranean region and are drought-tolerant, they still need water to thrive. The frequency and the amount of water they need will depend on the season, level of maturity, whether they are potted, or whether they grow indoors or outdoors.

Generally, small-growing rosemary plants will need two gallons of water while the more established larger plants will require at least 1 gallon of water. If growing outside during summer, grounded and potted plants will need more water given more frequently because weathering elements dehydrate the plants much faster. Rosemary planted indoors will need less water because the water is less likely to have evaporated.

To determine your watering schedule and the amount your plants require, you can measure the dampness of the top 1 inch of the soil using your finger, a ruler, or a moisture meter. When watering, it is also vital that you do not overwater or underwater because rosemary plants are sensitive to moisture changes in the environment.

Featured Image Credit: pilialoha, Shutterstock


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