How to Grow Lavender in the Midwest
Give lavender space, mulch and water
Provide room to grow. Kieran and Libbe O'Connor, who have nearly 4,000 lavender plants at Willowfield Lavender Farm in Mooresville, Indiana, space their plants 3 feet apart on mounded rows of well-draining soil. The extra space allows better air circulation to keep the plants healthy and improve production.
Use non-organic mulch. Deborah and Steve of Winding Brook Estate mulch their plants with white limestone pea gravel. The gravel mulch "sweetens" the soil, making it slightly alkaline (which lavender prefers) and reflecting light and warmth up into the plants. Use organic mulch only when first preparing the soil for new plants; after that, use gravel or rock. Wood mulch holds too much moisture and may promote mold growth.
Water until the roots take hold. Establishing lavender plants takes diligence, and you'll need to water new plants when they're dry to the touch. But once lavender is growing well, the plant is extremely drought-tolerant and doesn't need pampering or fertilizer. The fragrance everyone loves also makes it unattractive to rabbits and deer.