As for essential oils that have long shelf lives usually, they are the thicker ones, such as Cedarwood, Sandalwood, Patchouli, Vetiver and a few others. Exception to this thick oil quality will be the essential oil of Rose Otto.
The season for them is generally a short one. Begins in early July and last for 2 to 3 weeks. Black raspberries tend to ripen before most red raspberries varieties expect for the early ripening summer ones.
Raspberries should be fertilized each spring. Apply an all-purpose fertilizer (16-16-8, 10-10-10, or 20-20-20) the first year and ammonium sulfate every year thereafter. Apply one cup of ammonium sulfate (21-0-0) per 10 feet of row. Water Utilization.