Rhubarb season is relatively short, at around 8-10 weeks, and the window for picking is winding down. You need to know when to stop picking rhubarb each year to have strong crops next year. And that cutoff should be to stop in early July.
You can theoretically harvest rhubarb throughout the growing season. This is not advisable, though, as the plants need some time to recover from harvesting and replenish their energy reserves for the following year.
