Did you know . . .
While all lavenders have fragrance, there are some cultivars that seem to be the most fragrant. Some of them have been grown for lavender oil production. The fragrance and the quality of the oil can vary from year to year depending on how much sunlight the plants get, the soil they are grown in, the amount of water they receive (especially during spike development), and when they are harvested.
Extreme heat, wind, and dryness can cause the volatile sweeter notes to evaporate prior to distillation. Avoid using excessive amounts of fertilizer, including nitrogen-based fertilizers. And, never use strong manures such as pig or chicken manures. For the home garden, an application of well-balanced compost and some lime will benefit the plants. Remember that lavenders and lavandins love lime. They grow in stony, limestone soils in their natural habitat. They grow and yield best where there is adequate calcium in the soil, i.e., in a gritty, sandy loam with a pH factor between 6.0 and 8.0. Time may be added in the fall or be incorporated before planting.
The optimum time to cut the flowers for the best oil depends on the cultivars, but for the English lavenders it is generally when half the flowers on the spike have withered lavenders. The scent is generally sweeter towards the end of flowering for lavandins, when most of the flowers on the spike have withered.
To dry lavender and lavandin flowers on their stems, hang them in small bunches (secured with rubber bands), in a dark, dust-free place with good ventilation to allow for quick and complete drying. Once they are dried, place them loosely, in cardboard boxes and store them in a cool, dry, dark, are until you are ready to use them.