Choosing the right pot size is crucial for growing lavender successfully in containers, as it directly impacts drainage, root development, and overall plant health. Lavender absolutely hates "wet feet" and thrives in conditions that mimic its native Mediterranean rocky, well-drained soils.
Here's a breakdown of ideal pot sizes and related considerations:
General Rule of Thumb for Pot Size:
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Minimum Size: For most lavender varieties (even compact ones), start with a pot that is at least 12 inches (30 cm) in diameter and depth.
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Ideal Size for Most Varieties: A container of 16 inches (40 cm) in diameter and depth is often considered ideal for a single lavender plant, especially English lavenders and smaller Lavandin varieties. This size gives the roots enough room to spread without holding too much excess moisture.
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For Larger/Mature Varieties: If you are planting a vigorous Lavandin variety like 'Grosso' or 'Phenomenal' that can grow quite large (2-3 feet wide), or if you plan to keep the plant in the same pot for several years, you might opt for a larger pot, up to 20-24 inches (50-60 cm) in diameter.
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One Plant Per Pot: It's generally recommended to plant only one lavender plant per pot. If you want a fuller display, use multiple pots rather than crowding several plants into one container, as this will lead to competition for resources and poor air circulation.
Why Pot Size Matters for Lavender:
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Drainage: The biggest reason. A pot that is too large for a small lavender plant will hold an excessive amount of potting mix relative to the plant's water uptake. This means the soil will stay wet for too long, leading to the dreaded root rot, which is the number one killer of potted lavender.
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Root Development: While lavender likes to dry out, its roots do need space to grow. A pot that is too small will stunt the plant's growth and limit its ability to produce abundant flowers.
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Air Circulation: Larger pots (within reason) promote better air circulation around the root ball, which is vital for preventing fungal issues.
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Stability: Taller lavender plants can become top-heavy, especially when blooming. A wider, deeper pot provides better stability, preventing the plant from toppling over in windy conditions.
Ideal Pot Materials:
The material of the pot is just as important as its size due to drainage and breathability.
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Terracotta/Clay Pots: These are often considered the best choice for lavender. Their porous nature allows excess moisture to evaporate through the pot walls, promoting excellent drainage and aeration for the roots. This helps keep the soil on the drier side, which lavender loves.
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Unglazed Ceramic Pots: Similar benefits to terracotta, allowing for breathability.
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Fabric Grow Bags: These are also excellent as they offer superior aeration to the root zone ("air pruning" roots) and prevent waterlogging.
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Avoid (or use with extreme caution): Non-porous materials like plastic or glazed ceramic can retain too much moisture, increasing the risk of root rot. If you must use them, ensure they have ample and large drainage holes, and be extra vigilant with your watering.
Other Potting Considerations:
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Drainage Holes: This is NON-NEGOTIABLE. Your pot must have adequate drainage holes. Lavender will not survive in a pot without them. Adding a layer of gravel or broken pottery at the bottom for "drainage" is a common myth and can actually worsen drainage by creating a perched water table; instead, focus on a well-draining potting mix.
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Potting Mix: Use a high-quality, very well-draining potting mix. A good general recipe is a standard potting mix amended with significant amounts of perlite, coarse sand, or small gravel (e.g., 1 part potting mix to 1 part perlite/sand). Some specialty "cactus and succulent" mixes can also work. Lavender also prefers slightly alkaline soil (pH 6.5-7.5), so avoid acidic peat-based mixes or add a tablespoon of dolomite lime to the mix.
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Repotting: As your lavender grows, it may become root-bound. Plan to repot it into a slightly larger container every 1-3 years, ideally in early spring before new growth begins. When repotting, only go up one size (e.g., from 12-inch to 14-inch), and ensure the new pot still allows for good drainage.
By choosing the right size and type of pot, coupled with a well-draining soil mix, you can successfully grow beautiful, fragrant lavender in containers.
Lavender Farm in Door County Wisconsin. You can buy lavender products online at islandlavender.com