In Seedfolks, are the interactions generally positive or negative when people of different races interact with each other?

According to Sam in Paul Fleischman's novel Seedfolks, interactions between ethnic groups are generally negative. However, later in the book, during Nora's account, we see that there have been some positive changes.

Sam is the sixth character we meet in the novel. He doesn't plant anything in the garden, but he does solve the problem of how to get water to the plants. He sees it as his job to mend rifts in the neighborhood. He does this by smiling and striking up conversations with people, particularly people of different ethnic backgrounds. Here is his observation of the interactions between the ethnic groups in the garden:

"One Saturday, when the garden was fullest, I stood up a minute to straighten my back. And what did I see? With a few exceptions, the blacks on one side, the whites on another, the Central Americans and Asians toward the back. The garden was a copy of the neighborhood. I guess I shouldn't have been surprised. A duck gives birth to a duckling, not a moose. Each group kept to itself, spoke its own language, and grew its own special crops."

Later on, in Nora's account, we see positive changes that have taken place in the neighborhood.

"When the rain came that day, the other gardeners all ran in the same direction, as if in a fire drill. We followed and found them sheltered beneath a shoe store's overhang two doors down, apparently their customary refuge. In fifteen minutes, we'd met them all and soon knew the whole band of regulars. Most were old. Many grew plants from their native lands--huge Chinese melons, ginger, cilantro, a green the Jamaicans called calaloo, and many more. Pantomime was often required to get over language barriers. Yet we were all subject to the same weather and pests, the same neighborhood, and the same parental emotions toward our plants. If we happened to miss two or three days, people stopped by on our return to ask about Mr. Myles' health. We, like our seeds, were now planted in the garden."

This quote from Nora shows that though the accidental gardeners began the journey of the garden on Gibb Street isolated from each other, their shared experiences have bonded them together and given them all a sense of community that was strongly lacking when the book began. Their interactions have gone from nonexistent or mostly negative to largely positive.