Q.Beginner — what can grow fast after summer planting
I JUST got a plot in a community garden (very late, I know). Wondering what I can plant that might produce after being planted in July? I live in Philadelphia, and the garden gets full sun.

Go ahead and visit some garden centers. Many times the vegetable plants are still there and can be purchased rather inexpensively.
If you find pepper plants, they can catch up quite quickly in a warm garden. Even a cherry tomato plant may still have enough time to produce some fruit for you.
Other wise try beets, broccoli, carrots, cauliflower, collards, greens, kale, small onions, swiss chard, turnips.
And don't forget Herbs!
Maybe we will all be blessed with a long fall!
Happy Gardening!
https://www.gardeningknowhow.com/edible/vegetables/pepper/growing-peppers.htm
https://www.gardeningknowhow.com/edible/herbs/