Lavender, a fragrant and drought-tolerant Mediterranean shrub, is a desirable addition to any garden or container. While propagation from cuttings is often the fastest way to achieve a mature plant, growing lavender from seed offers variety and a rewarding challenge. Starting lavender from seed can be a slow process, with germination often being unpredictable and sporadic. To ensure successful establishment, a precise strategy for seed placement is necessary to maximize the potential for at least one healthy seedling per container.
Pre-Sowing Decisions: Pot Size and Germination Rate
The choice of container directly influences how many seeds you should sow. Lavender seeds naturally exhibit a low or inconsistent germination rate, sometimes as low as 20 to 30 percent without a cold stratification period. The two common goals for starting seeds are to produce a seedling for eventual transplanting or to grow the plant to maturity in a single, larger container.
For seedlings intended for transplanting, smaller cell trays or two- to three-inch starter pots are typically used. These diminutive containers are meant to house the plant only until it develops a robust root system. Conversely, a larger pot, such as one six inches or more in diameter, would be chosen if the plant is intended to remain there long-term. Understanding the low germination rate and your final planting goal determines the necessary seed density, ensuring you do not waste time waiting for a single seed that may never sprout.
Determining Seed Density Per Container
The number of seeds placed in any container is a calculated risk based on the likelihood of successful germination. For small starter pots or cell trays that are two to three inches wide, a density of three to five seeds per cell is recommended. This range accounts for the variable germination rate and provides the highest probability of obtaining at least one healthy seedling that can be transplanted later. The goal is not to grow a cluster of plants, but to guarantee a successful sprout.
When the objective is to grow a mature lavender plant in a larger, permanent container six inches or more in diameter, a slightly higher density is advisable. Planting a cluster of five to seven seeds in the center of the pot secures the presence of a plant, assuming you will thin later. These seeds should be placed slightly apart, perhaps a half-inch to one inch from one another, rather than piled together.
Essential Sowing Technique
Once the correct number of seeds has been determined, the method of sowing is crucial for encouraging germination. Lavender seeds require light to successfully sprout, a biological need that dictates a very shallow planting depth. Use a sterile, well-draining seed-starting mix, ideally one blended with sand or perlite to mimic lavender’s preferred arid soil conditions. The seeds should be pressed lightly into the surface of the soil or covered with no more than one-eighth of an inch of fine mix.
After placement, the initial watering must be done with extreme care to avoid displacing the surface-sown seeds. Misting the surface with a spray bottle or using a bottom-watering method, where the tray absorbs water from below, is the best technique. This keeps the soil uniformly moist without washing the seeds away, which is a common cause of failure in surface-sown varieties.
Post-Germination Management and Thinning
The strategy of planting multiple seeds per container necessitates a management step once germination occurs. Thinning is the process of removing excess seedlings to ensure the survival and healthy growth of the strongest individual plant. This step is imperative because multiple seedlings competing for the limited resources of light, water, and nutrients will all be stunted.
Thinning should take place once the seedlings have developed their first set of true leaves. Select the single, most robust-looking plant and eliminate the others by snipping them at the soil line with small, clean scissors. Avoid pulling the unwanted seedlings out of the soil, as this action can disturb the delicate root system of the chosen survivor. After thinning, maintain a consistent environment with ample light and moderate temperatures to encourage the now-dominant seedling to establish a strong root system.