In business terms, “verticals” are the business lines that fall underneath your overall brand (which is the umbrella, if you like), and then you have your horizontal functions which support across all the vertical businesses.
To take Meghan’s business as an hypothetical example, her umbrella will be the brand “As Ever”. Underneath that she might have different verticals being, say, Food, Homewear, Health Supplements and Fashion (I’m guessing that she might want to follow a Goop-like plan, obviously 😀 ).
Each of those verticals will have different products, suppliers, different advertising campaigns, and likely different target customers etc. Usually they would be supported by shared horizontal functions like HR, Finance, FDA compliance, legal etc.
So what she is basically saying here (I think) is that her various hypothetical different business lines will all be inspired by her love of home and garden. But I think Meghan thinks using jargon makes her sound more professional?