Rosemary likes to grow in a Mediterranean climate on sandy and stony slopes near the sea. In this area, the humidity is relatively high, but the soil does not retain much moisture. Ideal growing conditions will be well-drained soil and moist air around.
Water rosemary once every 7-14 days. However, it depends on many factors (outdoor, indoor, in pots, season, etc.). As a result, the frequency of watering and the amount of water will differ.
Next, we will consider watering instructions depending on the conditions in which rosemary grows. Of course, these will be average recommendations, and you always need to check the moisture of the top layer of soil (1 inch) and water only when it is completely dry.
Weather affects the watering frequency
When the weather is too hot, and the sun shines almost every day, and it has not rained for 10-15 days, then you will have to water more often, even though rosemary can tolerate drought.
Once a week for plants growing in garden soil will be the optimal watering schedule. The amount of water will vary depending on the plant’s size; on average, one gallon for small shrubs and two gallons for large ones.
For potted rosemary growing outdoors, you will have to water once or twice a week, depending on how quickly the soil dries. Water with a generous amount of water; when the excess water begins to flow through the drainage holes, it means that enough.
In cloudy weather, but still, in the absence of rain, watering should be reduced.
Water rosemary once every 10-14 days; the amount of water should be the same as in the previous case.
Potted rosemary needs watering once a week. The amount of water should be such that the roots are evenly moistened from top to bottom.
If it rained at least once in 10 days, then watering is not needed at all. Even if there were little rain and the soil is not completely wet, rosemary can collect moisture through the leaves. This moisture will suffice for a while, but watering in rainy weather can harm the plant.
In areas where prolonged rains often occur, rosemary needs special conditions. In this case, it is better to grow in pots with a large number of drainage holes and well-drained soil. If there is an excess of precipitation, move the plants under cover or indoors.
Watering in different seasons
For different times of the year, the frequency of watering will also be different.
Here particular attention should be paid to spring and the first half of summer. At this time, rosemary grows vigorously and forms new shoots, so it needs more moisture than usual.
If there was no rain for at least ten days during the period of active vegetation, you need to water the rosemary with two gallons of water.
For the plant to form thick shoots and leaves, it needs a lot of moisture. When they ripen, then watering should be reduced to regular frequency.
Suppose there is still no precipitation, water the garden rosemary once a week. For potted rosemary (outdoor), this can be even once every five days, depending on how much the sun shines and how quickly it dries the ground.
When the middle of the summer comes, and there is intense heat, the plant needs enough water. I have already written above about how to water in a drought.
In autumn, rosemary prepares for hibernation, so it needs a minimum of moisture. If there has been no rain for more than two weeks, you can give the plant a small portion of water.
For large rosemary bushes growing in the garden, one gallon for ten days should be enough. If the soil is dry at a depth of more than an inch, then the amount of water can be increased to two gallons. For small rosemary, the amount of water should be twice less.
If the plants grow in pots outdoors, they should be watered once a week, but again in the absence of precipitation.
Watering rosemary in winter
In winter, rosemary is at rest and uses internal water reserves, so it does not need watering. This is especially true if the winter is frosty and snowy.
However, in some areas where rosemary can grow, there are warm winters and several months without rainfall. In this case, little irrigation of the plant is still possible. Half a gallon every 20 days will be enough so that the rosemary does not lose too much internal moisture.
The amount of water depends on the type of soil
Depending on the type of soil, rosemary will need a different watering schedule. No matter what soil mix you plant them in, sooner or later, the roots will spread beyond the planting hole and will get water from the garden soil.
Soils can be divided into slow draining and fast-draining, so let’s talk about it a bit.
Slowly drained soils include heavy soils such as clay or black soil. They can retain large amounts of moisture and dry for a long time. As a result, the roots will be in too damp conditions, leading to root rot.
If you have this type of soil, you need first to take care of drainage. Before planting, dig a hole three times the roots’ size, fill it with a third of the material that is easily permeable to water (small stones, gravel). After that, you can plant rosemary.
Watering in this type of soil should not be frequent. In the summer, drought once every 10-15 days will be enough. However, if the heat is too intense, then you may need more frequent watering.
In the spring, when the plant grows vigorously, water it once a week in the absence of rainfall.
At other times of the year and in milder weather, watering in such soil should be done no more than twice a month.
Quickly drained soils have the ability to pass water easily. These include loam and sandy soil. This is the best substrate for rosemary.
However, in some periods, you will have to increase the frequency of irrigation in this type of soil.
In dry weather (mid-summer) and mid-spring, rosemary should be watered once a week or more often when new shoots are formed. It depends on the size of the plant and humidity.
In a sunny place, rosemary needs more water
It is known that rosemary likes to grow in places with full sun, but this is not always possible. Besides, growing in the sun in garden soil will be different from growing in the sun in a pot.
The first thing to say is if you grow rosemary in containers placed outside in the full sun. In this case, the pots should be large so that the soil is not too hot during a hot day.
In such conditions, watering will be required once a week (in the absence of rain). When watering, use a generous portion of water; its excess will quickly flow out of the pot.
During active vegetation and too hot summer, watering may have to be increased to once every five days. It depends on the rate of drying of the soil in the container.
If your rosemary grows in full sun in the garden soil, then the watering schedule will be regular; I already wrote about it above (watering is needed every 10-14 days).
Sometimes, it is impossible to plant rosemary in full sun, and the plant remains shaded for part of the day. There will be nothing terrible in this, yes, rosemary may be slightly elongated and will not be so thick, but everything will be fine in general.
In this case, watering should be less than as if the plant is growing in full sun. Once for 14-20 days is enough for healthy growth. An exception maybe when you have sandy soil and too hot weather, then water the rosemary every ten days.
Climate does matter
In the garden, rosemary can be grown from 7 to 10 hardiness zones. The climate in these areas is different, and watering will be different.
In colder climatic zones (7-8), the frequency of irrigation will be lower. Usually, once every 14 days is enough, it can vary depending on soil type and plant size.
In zones 9 and 10, it is necessary to water more often, namely once in 7 days, and, as in the previous case, the schedule can vary depending on conditions.
How to water?
No less critical topic than the frequency of watering is how to water the rosemary properly. So let’s dig a little deeper into this.
Best time for watering
As with most plants, the best time to water the rosemary will be in the morning when the sun is not yet too intense. At this time, the soil is slightly moist with dew, so the water penetrates better into the ground.
During the day, excess moisture evaporates and will not harm the roots. In the case of rosemary, it is perfect because these plants love moist air.
The disadvantage of evening watering is that at this time, the plants do not evaporate moisture and do not absorb water from the soil. As a result, the ground will be too wet for rosemary.
How much water?
On average, the amount of water for each rosemary bush should be one gallon. However, for small plants growing in the garden, half a gallon will be enough.
In extreme heat or the formation of young branches, the amount of water may increase. For adult rosemary, the amount of water can be up to two gallons if it grows in sandy soil.
For potted rosemary, the amount of water should be more generous – 1 gallon for small plants and 2 gallons for large plants in the same weather conditions as in the previous case. Excess water will flow through the drainage holes.
Watering technique
Watering can be done from a hose or watering can. If the surface is dry, water once with a small amount of water; after a few minutes, the water will wet the top layer, and then you can use the rest of the water. Otherwise, the water will spill over the surface.
Unlike some other plants, rosemary can be watered on the leaves. In this case, the plant will absorb moisture through the leaves.
You can use tap water. Do not use boiled water, as it no longer contains the minerals needed by the plant.
Watering newly planted rosemary
After planting, rosemary will require a special watering schedule. This is because the plant has not yet taken root, and changes in growing conditions can cause transplant shock.
Despite the weather conditions in the first few weeks (4-6), the plant’s soil should always remain slightly moist, not wet, but slightly moist.
To maintain the soil in this state, water the plant as much as needed. In hot weather, it can even be once every two days. However, this mustn’t last too long.
With a little rainfall, you need to check the soil moisture, and if it remains dry, you need to irrigate your plants lightly.
These recommendations apply to both potted and garden rosemary.
Within a month, the plant should establish in a new place, and watering should return to the usual schedule.
To reduce stress after transplanting, I recommend shading the rosemary for a few weeks. Just place a shading net over the plant or hide it from the sun under a patio umbrella.
Also, during the first week, you can spray the leaves with water; it will also soften the conditions and not allow the leaves to lose too much moisture.
Indoors watering
Everything written before does not apply to water rosemary indoors. Even if you grow rosemary in a pot from the outside, the watering schedule will still be different from potted rosemary indoors.
For proper cultivation, you need to choose pots with drainage holes to drain excess water. The number of holes should be at least 3-4.
Usually, for growing rosemary on the windowsill, people use small containers because there is little space. This entails certain difficulties, such as the rapid drying of the soil in the pot.
Due to the small size of the container, the soil can dry out in the sun for 1-2 days, and although rosemary is a drought-resistant plant, it still needs water to grow. This is especially true when growing rosemary in cold climates where the room is heated in winter.
In such conditions, watering will be required at least once a week and possibly more often if the potting mix dries too quickly.
Another disadvantage of growing indoors will be too dry air. To solve this problem, spray rosemary once or twice a day with water from a sprayer.
You can use one trick to avoid too frequent watering and not to dry the plant. In the photo below, you can see how it looks.
The trick is that you need to get a low plastic container and fill it with stones that can absorb water.
Next, you need to fill the container by a third with water and place a rosemary pot on top. The bottom of the pot should not touch the water but stand on wet stones.
Due to this, watering can be reduced to once every ten days. Even if the soil in the pot dries, rosemary will receive moisture from evaporating water.
You also need to refresh the water at the bottom of the container from time to time.
Overwatered rosemary
In fact, overwater rosemary is pretty easy. If you exceed the amount of water or the frequency of watering and your plant may get significant damage.
The first sign of overwatered rosemary is the yellow leaves. If you notice something like this, immediately pull the plant out of the pot and check the roots. If it is gray-brown and easily crushed with your fingers, then you have given the plant too much water.
The causes of overwatering are different.
First of all, it is excessive watering, and it usually happens with incorrect automatic watering. Do not point sprayers where rosemary is growing.
You can give the plant too much moisture when you water by hand from a hose or watering can. Therefore, do not exceed the recommendations of this article. Water the rosemary only when the top layer of soil has dried (at least one inch).
Prolonged rainfall can be another reason for the excessive amount of water. If it rains a lot in the area where you live, you should only grow rosemary in containers and move it to shelter when it rains.
How do you save overwatered rosemary?
If you do nothing when wet, then the plant may die.
First, you need to eliminate the causes of overwatering. I already wrote about it above.
Dig a plant out of the garden or pull it out of the pot and wrap the roots with a paper towel. In this way, you will dry the roots and soil. If some roots have rotted, then cut them off and powder the wounds with crushed ash.
Put rosemary in a dry pot and place undercover in partial shade. There should be good air circulation.
Do not water the plant for 2-3 weeks. Then start watering in small portions once every ten days. The recovery process can take quite a long time (a year or more).
If you can not dig rosemary out of the garden for some reason, you should divert rainwater from the plant. This can be done by digging a ditch through which water will be diverted away.
It will also be useful if you create drainage under the plant.
Too little water (underwatering)
Yes, it is possible. Rosemary is not a cactus, and it cannot store a lot of water, so even this plant can suffer from thirst.
This can often happen when you grow rosemary in a pot that is placed in a sunny place. In very hot weather, the pots dry out very quickly. As a result, the plant may be damaged.
The first sign of lack of moisture will be a change in leaf color. The color will be pale, not bright green. After a while, the leaves turn green-brown and later turn yellow and dry.
To avoid underwatering, you need to follow the recommendations of watering from this article.
If you do not water the rosemary in time, it is not critical; short periods without water, these plants can tolerate without damage. However, you should give the plant water as soon as possible not to be too late.
Key points
| Conditions | Frequency and Quantity |
| In garden soil | Water once every two weeks in the absence of rain. The amount of water is 1-2 gallons depending on the size of the plant. |
| In pots (outdoors) | Water once every 7-10 days in the absence of rain, with too much heat, maybe more frequent watering. The amount of water depending on the size of the pot. |
| In pots (indoors) | Water once every 7-10 days. If the sun is too intense, more frequent watering is possible. The amount of water should be sufficient to humid the soil in the container. |
| Spring | In spring, during intensive growth, garden rosemary needs watering every 7-10 days if there was no precipitation. Water the rosemary pot once every 5-7 days. |
| Clay Soils | In clay soil, you need to arrange drainage under the plant and water no more than once every 14 days (if no rain). |
| Fast Draining Soils | Quickly drained soils are best for growing rosemary. Water once every 7-10 days. |