Lavender is a forgiving plant and a lovely garden feature with silvery foliage, purple bloom spikes, and quintessential fragrance. It adapts to various conditions and thrives for years with a few of the best cultural practices in place. With the hot season upon us, knowing how much water to give lavender is helpful. These drought-tolerant plants don’t require much to thrive.
Lavender is a Mediterranean native. It grows naturally in warm, arid summers and mild winters in lean-to-average soils with excellent drainage. Plants thrive with a bit of neglect, and too much water leads to fungal diseases like crown and root rot.
Once established, the herbaceous perennial is relatively carefree. Plants are self-sustaining with average rainfall and supplemental water during prolonged dry spells. Suitable soils are key components to their success across growing zones.
How Much to Water
Water lavender deeply but infrequently to encourage robust root growth.
How much water lavender needs depends on site-specific factors, including soil type, plant size, and seasonal weather. For these sun-loving and drought-resistant perennials, it’s best to err on the dry side.
Young and newly transplanted herbs need consistent moisture, with water once or twice weekly. In most growing areas, established and mature plants require only minimal supplemental irrigation. Watering every two weeks and during hot and dry spells is beneficial.
As plants establish, provide a gallon of water once weekly in the first growing season (including rainfall). Increase the frequency during especially hot spells. For established plants, provide one to two gallons every ten days to two weeks. Depending on the climate, some growers push this frequency to three weeks so soils dry between sessions.
Lavender develops extensive roots that reach 18 to 24 inches deep. Plants with robust root systems are most resistant to pests, diseases, and environmental stress. When watering, the goal is to achieve a deep soaking around the roots.
Watering deeply—but infrequently—encourages a deep root system to support the plant during environmental stress like heat waves or cold snaps. Frequent shallow watering encourages roots that grow laterally and beneath the surface rather than deep into the soil. Shallow roots impact plant stability, hardiness, moisture absorption, and nutrient sources.
Check Soil Moisture
Check soil moisture to avoid overwatering.
Observing the plants and feeling the surrounding soil is the best way to determine if you’re watering enough or, with lavender, overwatering. We are apt to love these beauties too much by giving excess moisture.
Overwatered plants exhibit wilting and drooping flower stalks and stems. Underwatered plants wilt, too, as they do in extreme heat.
A simple touch test lets us know if soils are too wet or dry. If the soil feels damp and sticks to your fingers, oversaturation may be an issue. If soils are dry down to six inches, it’s time to irrigate.
Good drainage is essential for lavender and worth emphasizing. Waterlogged conditions lead to root and crown rot. Decrease irrigation if the soil remains overly wet.
Container-Grown Plants
Ensure container soil moisture to prevent fungal problems and underwatering.
Lavender growing in containers needs water if the soil feels dry to the depth of two to three inches (two knuckles deep or more). Underwatering may be an issue since containers dry out more quickly than in-ground plantings.
Overwatering stresses containerized plants and promotes fungal conditions. Ensure suitable drainage holes in the pots and employ a well-draining potting mix.
Overpotting may lead to overly wet soils. Overpotting occurs when a large pot houses a small plant, and the surrounding soils remain wet. Increase the length of time between pours or repot the selection.
Soil Type
Choose sandy or gravelly soil for optimal lavender growth conditions.
Optimal soils for lavender dry out between watering sessions. These Mediterranean herbs grow naturally in sandy, gravelly, rocky soils.
Soil type plays a significant role in the water needs of all plants. Fortunately, lavender is unfussy as long as the soil is fast-draining and not overly fertile.
To irrigate efficiently, it helps to know how local soils absorb and retain water. A simple soil test helps with this information. Typical soil types include blends of:
Clay has a slow absorption rate, slow drainage, and holds water. Water permeates slowly through the clay, retaining it like a pot. Clay soils may stay overly wet at shallow levels.
These are ideal soils for many plants. They contain organic material to aerate and retain moisture. The soil also blends clay, sand, and silt particles.
Sandy soils are the fastest-absorbing and fastest-draining. They dry out quickly. Sandy soils need about 1.5 inches of water to infiltrate 18 inches deep. They require more frequent irrigation to attain regular moisture.
Silt is smooth when dry and slippery when wet. With fine particles, this soil type, like clay, is slow-draining. It lacks grainy, sandy particles.
In clay, silt, and compacted soils, incorporate horticultural sand, pea gravel, or perlite to increase aeration and drainage. If your soil holds moisture and tends to stay wet, avoid overwatering, as “wet feet” promote root and crown rot. Consider growing plants in raised beds or pots.
Seasonal Conditions
During hot spells, monitor and adjust lavender watering accordingly.
Established lavender usually only needs water on the hottest, driest days, depending on your climate. In the desert, plants benefit from shorter lengths between sessions. In rainy climates, you may experience too much moisture for lavender’s preference. Grow them in containers with shelter to protect them from oversaturation.
When temperatures are consistently above 90°F (32°C), plants wilt as they naturally conserve energy, regardless of soil moisture. They’ll revive with cooling evening temps or as conditions level off.
In all cases, water needs relate to rainfall amounts. Cut back irrigation during rainy weeks, and pay attention to dry or windy spells and periods of intense heat for increased dryness. Increase watering during these spells, especially for young plants.
Cut back on watering if you’re overwintering the perennials in pots and containers. Potted specimens may only need it every few weeks.
When to Water
Early morning watering aids lavender’s health and resilience against diseases.
Water early in the day to prevent diseases like powdery mildew, botrytis, root, and crown rot. Morning water allows foliage to dry in the day’s sunshine and breezes. Overly damp and humid conditions harbor fungal spores that damage plants.
Early watering also provides resources for the herb during the day’s heat. They benefit from the deep soaking before evaporation from the soil and transpiration (natural water loss through pores in the leaves).
How to Water
For healthier lavender, avoid overhead watering to prevent fungal issues.
To prevent diseases and pests, avoid overhead watering. The routine splashing of leaves, stems, and crowns increases those fungus-loving damp conditions. Lavender is leafy with woody stems that may inhibit air circulation within plants.
We know lavender benefits from rain, and overhead water is not detrimental, especially after a drought. If relying on spray heads, disease prevention is best when watering occurs in the morning and plants dry in the sunshine. Skip overcast days and avoid evening watering. Irrigate only in excessive dryness.
Water at the base of the herb slowly and deeply to soak the roots. A watering can, drip irrigation, and soaker hoses efficiently deliver consistent, low volume with little runoff. Place tubing or hoses six to eight inches away from stems to prevent rot and to deliver moisture to the roots and surrounding soil.
