Basil is a herbaceous plant that lacks a woody structure to support itself and therefore it relies on a constant supply of moisture in the soil and persistent transpiration for structural support (know as turgor pressure) so that the basil stems and leaves do not wilt or droop.
Water basil as frequently as required to keep the soil moist but not boggy. Basil droops if the soil dries out. In most circumstances water basil at least once, every 3 or 4 days to keep basil healthy. Adjust the watering frequency if temperature or sun exposure increases, to maintain soil moisture.
The amount you should water basil can variable according to whether basil is planted in pots or in garden soil, the amount of sun exposure and according to your climate.
Here is a helpful summary of how often to water basil to maintain a healthy plant and to avoid root rot caused by over watering:
|Basil Conditions:||How Often to Water Basil:|
|Basil in pots and containers:||Water once every 3 or 4 days with a good soak with water trickling out the base.|
|Basil in garden soil:||Water once at least once a week. Add mulch to retain moisture. Increase water to every 3 or 4 days if there is no rainfall or in high temperatures.|
|Basil indoors:||Water once every 4 or 5 days and ensure the soil is moist and not boggy.|
|Basil in hot weather:||Water once every 1 or 2 days in very hot weather if planted in pots and once every 2 or 3 days in the garden in times of drought. Monitor the soil moisture to a fingers depth and adjust your watering frequency to maintain consistent soil moisture and avoid the basil wilting.|
|Basil in cool, overcast or temperate climates:||During cool weather with some rainfall water basil about once per week. Check the soil for moisture to a fingers depth if you are unsure whether to water. If it feels only slightly moist, ensure you give the basil a good soak.|
|Basil seedlings:||Water basil seedlings once every two days and water in the morning. If the temperature is high and the soil is noticeably drying then water every day with a good soak.|
When watering basil is is important to soak the soil (rather then a light watering) as this encourages roots to grow and establish in the soil which increases the basil’s hardiness and resilience.
Always water basil in the morning to charge the plant with water before a potentially hot and dry day ahead.
There are some important factors when caring for basil that affect how often basil plants should be watered, such as the size of the pots or containers in which they are planted and whether the soil has been amended and mulched with moisture retaining compost and whether you are watering seedlings or established plants.
Keep reading to learn more about watering basil according to different conditions…
Watering Basil in Pots and Containers
Pots and containers are great for growing basil as they have favourable drainage conditions and you can control the soil profile by planting basil in good compost which helps to retain water as (well watered plants are crucial for the quality of the flavour and aroma of basil leaves).
Water basil in pots and containers around once every 3 days in Spring and Summer to keep the soil consistently moist and prevent the basil from wilting.
However, basil grows its best in terms of flavour, aroma and number of leaves when in full sun and on very hot days the pots can dry out quickly which can cause the basil to wilt.
The way to mitigate the risk of the soil drying out is to:
- Carefully monitor the soil moisture in times of hot weather by checking to a finger depth if there is any moisture. As soon as the soil feels somewhat dry give the basil a good soak so that water trickles out of the drainage holes in the base of the pot. With careful monitoring it is easy to work out how frequently to water your basil to keep the soil consistently moist so that the plant is healthy in your climate.
- Plant basil is a larger pot. Basil can survive in small pots but it thrives in pots that are at least 12 inches across. A larger pot contains more soil and therefore has a greater capacity to retain moisture therefore you should not have to water your basil as frequently. Small pots often dry out too quickly in full sun which causes the basil to wilt as a sign of stress.
- Use clay, terracotta or ceramic pots for planting basil rather then plastic or metal pots and containers. Basil from shops or garden centers often is planted in thin plastic pots. The thinner plastic pots and metal pots conduct heat from the sun more efficiently then pots made from ceramic, clay or terracotta. This means that the soil increases in temperature quickly in full sun which causes water to evaporate from the soil so there is less moisture for the roots of your basil plant causing it to wilt
Always plant basil is a good size pot made of clay, terracotta or ceramic and the basil should only require watering every 3 or 4 days in summer with a good soak. If there have been many overcast day and some rainfall, basil may only require watering once per week.
(If basil plant is wilting read my article, why basil wilts and how to solve it).
Top Tip: Basil requires soil that is moist, yet well draining to prevent boggy soil and excess water around the roots that can cause problems such as root rot.
To maintain this balance, plant basil in a pot with drainage holes to allow excess water to escape. Try to avoid the use of a drip tray or placing your basil pot on a saucer as this can catch the excess water and cause the soil to be boggy rather then well draining.
If you are growing basil indoors, place a paper towel under the basil pot to allow water to drain from the pot and to prevent water trickling out onto your window sill or onto your furniture.
Pots and containers are the best way to prevent slugs eating basil. Read my article for a method of stopping slugs eating your potted basil that actually works!
Watering Basil in Garden Soil
How often you should water basil that is planted in garden soil can vary according to a number of factors such as hot weather, wind, rainfall and humidity.
However if the basil is planted in rich soil that has been amended with plenty of compost to retain moisture and the area around the basil has a good application of mulch then basil should be watered twice per week in hot weather and once per week in cooler weather to maintain its structure and to ensure a healthy plant.
The more compost, leaf mould or manure you use to prepare the soil before planting basil the more moisture there is available around the roots of the basil and therefore the plant is more resilient in times of drought or during blazing sunshine.
Apply a 1 inch layer of compost as a mulch on the surface around the basil to ensure the soil stays moist after water and to decrease the rate of water evaporating from the soil on hot sunny days.
Always water the basil at the roots with a good soak to encourage good root development.
If you have slow draining soil such as heavy clay then you should water your basil diligently, keeping record of the soil moisture (slow draing soil can cause root rot) or plant the basil in a pot with well draining compost.
Basil requires moist soil (such as good compost) but slow draining, boggy soil can lead to root rot.
(Read my article, how to revive a dying basil plant).
Watering Basil Indoors
Water basil indoors as often as every 4 or 5 days to ensure the soil stays moist. Basil requires full sun so locate the pot by a sunny window sill and ensure the pot has drainage holes in the base so excess water can escape.
If you notice the soil looking dry at the surface, check for moisture to a fingers depth and if the soil is somewhat moist but perhaps drying out, give your indoor basil a good soak to keep it healthy.
Certain rooms of the house (such as the kitchen) tend to be more humid which decreases the rate of evaporation from the soil and keeps the plant hydrated whereas rooms with air conditioning or draughts will require more frequent watering of around every 3 to 4 days to avoid the basil wilting.
Smaller pots also dry out much quicker as there is less capacity to retain moisture. Water basil in small pots every 2 or 3 days or ideally, plant the basil in a larger pot (around 12 inches across) which improves root development and the health of the basil so it grows more leaves.
Watering Basil Seedlings
It is important to maintain a good balance of moisture whilst basil seedlings are developing roots.
As with all basil plants, the aim is to maintain a moist soil without it becoming boggy as this can lead to fungal disease and root rot.
With seedlings careful monitoring of the soil moisture and watering accordingly is more important then general watering instructions as there are a lot of variables that can either dry out the soil or maintain its moisture.
Watering basil seedlings once every two days is usually the best practice as long as the soil is well draining yet retains moisture.
As basil seedlings haven’t fully developed their roots they are even more vulnerable to drought compared with establish plants, so ensure the top few inches of the soil are consistently moist and water in the mornings to charge the basil seedlings with water before a warm and sunny Spring or Summers day.
- Water basil every 3 or 4 days to keep the soil consistently moist. In high temperatures with blazing sunshine water basil once every 1 or 2 days to ensure the basil has sufficient water.
- Monitor the soil and adjust the frequency of your watering of basil plants according to the conditions of your garden.
- Pots and containers often require more water as they can heat up in the sun. Choose a larger pot of around 12 inches across to help retain moisture in the soil and avoid metal or plastic pots as they conduct more heat and dry out quicker.
- Water indoor basil consistently once every 3 or 4 days as it does not receive water from the environment and increase watering frequency if the soil dries out.
- Basil seedlings require moisture almost every day to keep the top of the soil moist as the roots have not developed properly.
- Amend garden soil with compost and use a mulch to help retain moisture and water once every week.
- Basil prefers soil that is moist but not boggy so ensure that the soil is well draining and plant basil in pots with drainage holes in the base.