Irrigate thoroughly, but less frequently, to develop a deep root system for increased drought resistance. Do not use black plastic weed barriers. They reduce air circulation. Install an underground system of perforated drain tile to remove excess water, lower the water table and increase oxygen and carbon dioxide flow around roots. Fertilize only well established plants.
Lavender grows well in low nutrient soil.
Analyze soil first and provide only missing nutrients. Examine plants regularly. Remove and dispose any diseased material immediately. Rotate crop to lower risks of fungal infection.