Yes, secure spot early. Weekends get crowded.
Yes, bring your own picnic. There's a children's playground, cute floor sprinklers for kids to run through and cool down in the heat of the summer, misting stations, a volleyball court, Tacocina (Danny Meyers' taco stand), and sometimes there are food truck/stand vendors too. Weekends are especially crowded so go early to stake your claim on a piece of land for your little ones!
There were many picknicks when i was there. If you're a big group I'd recommend going to a community garden. It's the same are, but has entrance from a street. It has more space, picnic tables.
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