Laurel's mom is a naturopath, and she sure seems to live the natural lifestyle. The first time we see her, after Laurel's first day at public high school, she's kneading bread, and she's also got a "long braid" (8.6) and used to play a guitar at sit-in protests in Berkeley. Yep, that's about as crunchy-granola as people come.
Among other hippie traits, like not trusting Western medicine, Laurel's mom is also skeptical of written contracts and anything written in legalese, so it's a huge shock to Laurel when she signs all the forms that Barnes has brought in without a fuss. But as she explains to her daughter, "'I don't have a choice anymore. Because of these hospital bills, we're drowning in debt'" (18.43). It's terrible that Laurel's mom decides to sell the land to Barnes, but what else can she do? She has a family to take care of, and she needs money in order to do so.
Along this line, Sarah definitely wants the best for her daughter, and she doles out plenty of motherly advice, such as: "If your clothes are enough to drive would-be friends away, they're not the kind of friends you want" (1.74). She also compromises on Laurel's weird eating habits:
That's why her mom finally agreed to keep the fridge stocked with Sprite. She railed against the as-yet-undocumented detriments of carbonation, but she couldn't argue with the 140 calories per can. That was 140 more than water. (1.113)
See? She's a flexible lady. Laurel's mom engages in typical mom stuff like taking a ton of pictures of Laurel and David before letting them go to the school dance, and like any mom, she occasionally does awkward things, such as reminding Laurel that "just because you haven't started your period doesn't necessarily mean you can't get pregnant" (15.13). In other words, she might be a hippie, and she might be raising a faerie, but she's still a mom, through and through.