Watering Rosemary (How Often and How Much to Water)

Rosemary is a woody perennial that hails from a Mediterranean climate. Therefore, it’s quite used to hot summers with minimal rainfall. Rosemary also grows naturally in sandy soil that is near the ocean. In these areas, the humidity is relatively high, but the soil does not retain a lot of moisture.

In general, you should water rosemary every 7 days in Summer and every 2 weeks in Spring and Fall. You should give your rosemary plants at least 1 gallon (3.8 liters) for small plants and 2 gallons (7.6 liters) for larger plants.

One important consideration when deciding when to water is to check the top 1 inch of the soil. If it feels dry, then it’s time to give your plants some water. However, if the soil is still damp, then you can hold off for a couple of days.

Let’s discuss the factors that determine how often and how much you need to water your rosemary plants.

How Often To Water Rosemary

How often you have to water your rosemary plants depends entirely on where you live and the season. Whether the plants are ground outdoors in the ground or in large pots also has a bearing on how often you need to water them.

During the heat of summer, your rosemary plants that are grown in the ground may require water from you once a week, while plants grown in pots in full sun may require watering every couple of days. This is especially the case if you haven’t received any rain for the entire week.

However, if there has been a shower or two of rain, you might find that your plants are perfectly hydrated and may not need any more water for another week.

The best way to determine whether your rosemary plant needs water is to check the top 1 inch of the soil either with your finger, a wooden chopstick, or a moisture meter. If the soil is totally dry and crumbly, it’s time to give your plant some water. On the other hand, if the soil is slightly damp and sticks to your finger, then you can leave it for another couple of days.

How Much To Water Rosemary

As a general rule of thumb, a small rosemary plant only needs around 1 gallon of water every time, while a larger plant that is a little more advanced and woody will require around 2 gallons of water.

Ideally, you want to drench the soil around the plant but not so much that the water pools and doesn’t drain away. Rosemary does not handle being waterlogged and needs good drainage at all times.

For pot-grown plants, it’s best to add enough water until the excess drains out from the bottom of the pot. This is an indication that all of the soil in the pot has been moistened and means that this moisture is now available to the roots of the plant.

Plants Grown In The Garden In Different Seasons

If you grow your rosemary outdoors in the garden, when you have to water your rosemary is often determined by the weather. Obviously, in summer, when it’s hot, and there’s no rain, your plants will require more frequent watering. However, if you live in a region that experiences a lot of humidity, the plants will be able to get some moisture from the air.

Rosemary is relatively drought-tolerant, but to get your plants to flourish, it’s best to give them enough water to keep them well hydrated. So, let’s look at some estimates of when and how much to water, depending on the seasons.

Watering Rosemary Grown In The Ground In Summer

If your rosemary is growing outside in the garden in summer and it’s constantly sunny, you should expect to water your plants once a week and apply around 1 to 2 gallons of water each time. However, if you get some rain during the following week, you may not need to give your rosemary any additional water if the top inch of the soil is still a little moist.

When watering, small rosemary plants should only require 1 gallon of water, while larger shrubs will require around 2 gallons of water at each watering session.

On the other hand, if you’ve been experiencing some cloudy weather even though it hasn’t rained, you should only have to water your rosemary every ten to fourteen days with the same amount of water as above.

If you live in a more sub-tropical climate and it tends to rain every ten days, or more frequently, you won’t have to worry about giving your rosemary any additional water.

Watering Rosemary Grown In The Ground In Spring

In spring, your plant will start to grow quite vigorously as the weather starts to warm up. It’s also the time that you will have applied some fertilizer to encourage new growth. However, the sun is not too hot yet, so there won’t be quite as much evaporation, and the plants won’t be stressed by the burning sun.

During this time, you should only have to water your rosemary around once every two weeks with about 1 to 2 gallons of water, depending on the size of the plant.

Once again, if it rains during a two-week period, you won’t need to water at all as long as the top inch of the soil is not completely dry.

Watering Rosemary Grown In The Ground In The Fall

In the fall, the weather is starting to cool down again, and your area may be experiencing more rainfall. In this case, you might only have to water your rosemary once every two weeks. Give your plants one to two gallons of water each, depending on their size.

Once again, if you’re receiving rain at least once a week, there’s no need for you to give your rosemary additional water because the temperature is not as high and the sun is not as hot.

Watering Plants Grown In Pots In Different Seasons

If you grow your rosemary in pots, be aware that these plants will require watering more often. This is because the soil inside a container is going to dry out a lot faster and the plant has limited space for the roots to grow in search of moisture.

Like plants grown in the ground, this will vary with the seasons and whether your pots are indoors or outdoors.

Watering Rosemary Grown In Pots Outdoors In The Summer

Rosemary plants that grow in pots outdoors will require watering at least once or twice a week, in general. However, if the temperatures are high and your plants are exposed to the full sun most of the day, you might find that you need to water daily during those times.

The amount of water that you give your plants shouldn’t vary too much, though. Give small plants around 1 gallon of water and larger, more established shrubs around 2 gallons of water. You’ll also find this comparative to the size of the pot that your plants are growing in.

As a general rule of thumb, you should water your pots until the excess starts to come out of the drainage holes. This ensures that all the soil in the pot is moist.

Watering Rosemary Grown In Pots Indoors In The Summer

When your pots are indoors, they’re not exposed to as much direct sunlight or drying winds. Even if your indoor temperatures are quite warm, these plants should only require watering once a week.

When measuring the quantity of water, you can give your indoor plants a little less because it’s unlikely that the soil in the bottom half of the pot will dry out completely. This is because the pot is not exposed to direct sunlight.

For small plants, half a gallon of water should be sufficient. For larger plants that are grown in larger pots, 1 gallon of water should be enough.

Watering Rosemary Grown In Pots Outdoors In Spring

Whether your rosemary is growing in a container or in the ground, it’s going to be putting on a lot of new growth, especially in early spring. Therefore, it’s going to need regular watering to support all that new growth.

Rosemary that is growing in a pot outdoors should be watered every ten days or so, depending on the temperature and how quickly the soil is drying out.

Give your small plants around 1 gallon of water and double that for larger, more established plants.

Watering Rosemary Grown In Pots Indoors In Spring

Even if your rosemary is growing indoors in a pot, it’s still going to be putting on a lot of new growth in spring. Therefore it should be watered every ten days. Make sure that you check first whether the top inch of soil is dry. If there’s still a little moisture in the soil, hold off giving additional water for a day or two.

Give your plant around half a gallon of water during this time.

Watering Rosemary Grown In Pots Outdoors In The Fall

Once the heat of summer is over, rosemary grown in pots outdoors is going to start needing less water. At this time, you can reduce the watering frequency to once every ten days. It’s important to keep monitoring the moisture level in the soil in case you get an unexpected heatwave.

As before, one gallon of water is enough for small plants, while larger, more established ones need twice that much.

Watering Rosemary Grown In Pots Indoors In The Fall

When your rosemary is growing indoors, it’s not exposed to the elements, but it still needs to be monitored so that it’s receiving enough water. At most, your plant will need a top-up once every ten days, but this depends on whether the soil has dried out or not.

You should only have to give your plant half a gallon of water at this time.

Watering Requirements During Winter

In winter, your rosemary perennial plants will slow down their growth and won’t need additional watering unless you experience long periods without rain. If your winters aren’t frosty and snowy and your rosemary is growing outdoors, it should get enough rain to sustain it through the cooler weather.

Even plants grown in pots should be fine as long as they get some exposure to regular rainfall.

If you live in a region where rosemary will not survive outdoors during the winter, you’ll have to bring your plants inside. If this is the case, you should only have to give your plants around half a gallon of water once every 20 days during the cold months of winter.

How To Water Your Rosemary To Get The Best Results

The best time to water your rosemary plants is early in the morning, before the sun has had the ability to build up too much heat. If you water in the full heat of the day, you’ll find that the water will evaporate too quickly before it has a chance to travel down into the soil.

Watering in the evening is also not a good idea for rosemary plants because excess water cannot evaporate, so the soil will remain quite damp throughout the night. This is not ideal for rosemary plants.

Ideally, you want to aim the water at the roots so that it can soak down into the soil, and the roots of the plant can then take up the moisture as the plant needs it.

The most important thing to remember is to give your rosemary plants a watering when the top inch of the soil feels dry to the touch. This is regardless of whether your plants are growing outdoors in the garden or in containers.

Therefore, you should check the moisture level of the soil at least every couple of days in the summer and at least once a week in the other seasons. Only water if the soil feels dry and follow the recommended water quantities.