How To Care For Lavender House Plant. Water your lavender after planting and then pull back on the water. Care for French lavender in winter by planting them in well draining soil and do not water them if they are left outside as wet soils in winter will cause fungal disease.
This is why dry and sandy substrates that dont retain water are recommended. To grow a French lavender hedge plant one stem every 12 to 16 inches 30 to 40 cm. If planting in containers the pot needs to be at least 30cm wide.
Water once the top inch of soil dries out fertilize twice per year and provide low humidity and moderate temperatures.
Add a drainage layer made with small gravel or clay pebbles. Dig over any free-draining soil and remove the weeds before planting. Use a loose soilless mix for planting and remember that container-grown lavender will require more water than garden-grown plants. Remove leaves and organic material from around them that hold moisture.