The smell of CBD hemp is in the air — and how!

In parts of the mid-Hudson where farmers are growing hundreds of acres of cannabidiol hemp for the first time, the rapidly maturing plants are producing an odor so strong that it can easily obscure the usually pervasive smell of September, the smell of onions and apples being harvested.

The odor is widely described as resembling the distinctively pungent smell of a dead skunk. In fact, several strains of CBD hemp seed incorporate “skunk” in their names.

“Sure, you can smell it over the onions when you drive through the Black Dirt, but there’s worse stinks by far,’’ said Maire Ullrich, agricultural program leader at Cornell Cooperative Extension Orange County.

“Think about the love-hate relationship most people have with cilantro, for example,’’ she continued. “Agriculture produces lots of sights, smells, sounds that people don’t like. It’s the nature of the business.”

The odor is especially pronounced now because hemp plants have morphed from tiny seedlings into tall, leafy bushes in their march to maturity and harvest in October. The plants rub against each other readily, bruising their leaves, releasing oils and amplifying the smell.

“I haven’t heard any complaints,” said Paul Ruszkiewicz, a Black Dirt farmer and president of the Orange County Vegetable Growers Association. “I don’t find it offensive but that’s me and I realize somebody who lives close to a field and smells it all the time could feel differently.”

Ullrich, a member of Cornell University’s new hemp team, said plants from pines to roses to oranges get their characteristic smells from compounds called terpenes.

And CBD hemp’s terpenes seem to interact with other compounds to produce the plant’s reputed stress and pain relief benefits. Terpenes play a similar role in lavender, a plant considered to have calming properties.

The smell, Ullrich said, is harmless. CBD hemp belongs to the same plant family as marijuana but has a different composition and doesn’t produce a high.

More importantly, the fields don’t produce any pollen to trigger allergies. Only female hemp plants produce CBD and pollination can reduce its strength. Growers, as a result, have to constantly monitor plantings for rogue males or pollinated females and remove them.

Cornell has estimated that as many as 1,500 acres of hemp were planted in the Hudson Valley this spring. Farms in Orange, particularly in the Black Dirt region, and Ulster counties account for more than half of the acreage.