Lavender seems like it ought to be effortless to grow from seed. Mature bushes thrive in sunny dry borders, so it is tempting to scatter a packet onto gravel and expect fragrant flowers a few weeks later. In reality, lavender seeds can germinate unevenly, and young seedlings need more controlled moisture than established plants.
Starting them in seed trays is often more reliable than direct sowing. You'll need patience, suitable seed compost, plenty of light and a careful transition to the dry well-drained conditions adult lavender enjoys.
Choose the lavender species first
English lavender, Lavandula angustifolia, is a familiar hardy garden choice in the UK. French and Spanish types have different winter requirements and may be less hardy in cold exposed sites.
Read the packet for the scientific name and specific germination directions. Seed-grown plants can vary in flower colour and habit, especially compared with named cultivated varieties propagated from cuttings.
If you want an exact clone of an existing lavender, cuttings may be a better method than seed.
Think about your final growing space
Lavender needs sun and soil that drains well. The RHS recommends bright positions and warns that wet winter conditions can damage roots.
Choose a bed, raised area or container that will not stay saturated. A sunny position behind a wall can suit some varieties, while a cold exposed northern garden may require more hardy English lavender.
Don't germinate a dozen plants without deciding where mature shrubs will fit. Some cultivars become much wider than their tiny seedlings suggest.
Read the seed packet carefully
Lavender varieties differ in whether they benefit from cold stratification and how long they take to germinate. Follow the instructions supplied for the actual species.
Some seed suppliers recommend a period of moist chilling to improve germination, while others advise direct sowing into compost at a specified temperature.
Don't assume one fridge trick guarantees success for every lavender seed. Seed age, storage and variety also affect results.
Prepare a clean seed tray
Fill a clean tray or small modules with suitable peat-free seed compost. It should be fine enough for tiny seeds and free from large lumps that obstruct emergence.
Moisten the compost before sowing so a heavy watering can doesn't wash the seeds into one corner.
Leave enough drainage to prevent standing water. Wet compost that never dries slightly between waterings can encourage damping-off in seedlings.
Sow at the correct depth
Lavender seeds are small and often require only a very light covering. Some varieties need light for germination, so the packet's depth instructions matter.
Sow thinly rather than pouring the entire packet into one tiny pot. Crowded seedlings are difficult to separate without damaging fragile roots.
Label the tray with species, variety and date. Lavender can take longer to germinate than fast annuals, and you may otherwise forget what is growing.
Provide appropriate warmth and light
Place the tray where the specified germination temperature can be maintained. Many lavender seed instructions recommend moderate warmth rather than an intensely hot windowsill.
Keep the compost evenly lightly moist, not saturated. Covering a tray may reduce evaporation, but ventilate according to the propagation method to avoid excessive condensation.
Once seedlings emerge, give them bright light so they develop compact growth. Low light and excessive warmth can make weak elongated stems.
Be patient with uneven germination
Don't throw the tray away because nothing has appeared after a week. Lavender germination can be slow and inconsistent compared with vegetables such as radishes.
Follow the packet's expected window, then reassess temperature, compost moisture and seed freshness if germination is poor.
Constant digging through the compost to look for seeds can damage emerging roots. Give the process time.
Thin or prick out seedlings carefully
When seedlings have developed true leaves and can be handled, move them into small pots or thin overcrowded trays as appropriate.
Lift using a dibber beneath the roots rather than pulling by the delicate stems. Handle the leaves gently if you need to support the plant.
Use a suitable gritty free-draining growing mix. A large wet pot can be difficult for a tiny seedling to occupy without root problems.
Water young lavender differently from mature plants
Young roots need moisture to establish, but they also require air in the compost. Let the surface dry slightly as appropriate while avoiding severe dehydration.
A mature lavender may tolerate dry spells far better than a seedling in a small cell. Don't apply established-plant drought advice directly to germinating seeds.
Avoid keeping pots on saucers permanently filled with water. Drainage is essential at every stage.
Harden plants off before planting out
Seedlings raised under cover need gradual exposure to outdoor sun, wind and cooler temperatures. Begin in a sheltered spot during mild weather.
Increase outdoor time over several days and bring them in when frost is forecast. Sudden exposure can scorch tender growth or check development.
Only plant them permanently when weather and soil conditions suit the species, especially for less hardy lavender types.
Prepare a free-draining planting hole
For garden planting, loosen the surrounding soil and check that water doesn't stand in the hole. Lavenders dislike a compacted wet base.
The RHS recommends avoiding overly rich wet conditions. In heavy clay, a raised bed or suitable container may provide a better option than adding a small pocket of gravel beneath the plant.
Plant at approximately the same level as the original pot and firm gently around the root ball.
Space plants for their mature width
Check the seed variety's expected spread. Even small English lavender seedlings can become broad shrubs after several seasons.
Good spacing allows airflow and avoids a dense damp mass where disease and woody weak growth may become problems.
For a low hedge, plants can be set closer than individual display shrubs, but follow an appropriate spacing plan rather than guessing.
When will seed-grown lavender flower?
Flowering may not be impressive in the first season. Young plants need time to develop roots and branch structure.
Avoid excessive fertiliser intended to force immediate growth. Soft lush shoots may be less resilient than steady compact development in suitable soil.
By later seasons, well-established plants can flower reliably when given enough sun and correctly timed pruning.
Prune at the right stage
Lavender benefits from suitable regular trimming once established, but cutting hard into old leafless woody stems can damage many types.
Follow RHS guidance for the species. Young plants may need light shaping rather than severe pruning.
Remove faded flower stems at an appropriate time and avoid cutting everything back just before severe frost.
Mistakes to avoid
Sowing too deeply, using waterlogged compost and giving seedlings insufficient light are common causes of failure.
Another is planting tender species outdoors in cold wet winter soil. Species choice matters at least as much as seed germination technique.
A realistic first attempt
Start a small labelled tray indoors, follow the packet's warmth or chilling instructions and grow on only the healthiest seedlings.
Lavender from seed rewards patience. Once established in a sunny well-drained place, the resulting plants can provide fragrance and flowers for years.