Eighteen people participated in the official tweet up, according to Obama Foodorama. They were invited into the White House to prepare a healthy meal.
The White House streamed the event on its website, where Obama was seen working in the garden and joking with the kids.
The campaign's Twitter page re-tweeted one participant's description of a moment between Obama and one of the children helping out with the harvest:
The Democrats also promoted the hashtag #AskMichelle as a way to ask the First Lady questions about the campaign.
Michelle Obama does not have her own Twitter page.