When growing lavender I mix peat free compost with some sharp sand and grit, My adding sand and grit you will make your compost much lighter and youll increate drainage. This will make your lavender Planting Spring flowering Bulbs in Containers 5 Biggest Mistakes Made When Starting Seeds Indoors Air Plants Tillandsia araujei Purple star 3" Container Plants for Shade BBC Gardeners World Magazine When to Start Sowing Seeds: the Earliest Seeds to Start Indoors