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Unfortunately, as IUnfortunately, as I understand it, once a spinach plant starts to bolt, you can't reverse it. Spinach begins to bolt due to increasing daylight (about 14 hours or longer) as well as warmer temperatures. You can continue to harvest the leaves for now until they become too bitter; in late summer (after temperatures have cooled a bit) or early fall, you can plant some more for a fall crop.

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