Nigella Seeds - Black Onion Seeds

I recently watched a cooking show, where the cook made crispy breadsticks, coating them with what she called black onion seeds, as you would use say sesame seeds. Then later in the show she said the onion seeds were actually nigella seeds. My question is, I grow nigella in my garden, also known as Love-in-a-mist, are this also the culinary black onion seeds or is it another kind of nigella seed and could I grow that in my garden and what would be the best way to harvest it.

Nigella seeds, also called black onion seeds, have a nutty, peppery flavour. They are used in Indian and Middle Eastern cooking for vegetables, legumes and breads.
There are two types of nigella. Love-in-a-mist is listed in the Richters catalogue as "nigella"; the botanical name is Nigella damascena. It is not the same as the black onion seed variety of nigella used in Asian cooking. This latter variety is listed in the Richters catalogue as "cumin, black" and the botanical name is Nigella sativa.
The seeds of both types are used in cooking, but the latter is the commonly used one and is the authentic one for recipes calling for black onion seeds.