Use a Mix of Tactics
The best possible succession system uses various tactics. The most straightforward way to produce more cilantro, chard, bush beans, arugula or lettuce, among other possibilities, is by repeatedly sowing a small amount in a dedicated area.
In spring, I set aside space that could accommodate a few successions, but sow just the first, in a portion of that row. Two (or, for the beans, three) weeks later, I sow the second stretch. By the time I sow the third, I’ll probably be harvesting or even pulling the first, and could reuse the first space for a fourth sowing or for planting something else.
In other spots, I follow one crop that’s ready to be pulled with a different one. So my plan would call for growing early spring spinach to harvest before the tomatoes are transplanted there, and planting garlic in that space in October after pulling the tomatoes.
Here’s a sort of hybrid of the first scenario: Sow two or more varieties of the same vegetable at the same time, choosing ones with a different number of days to maturity listed in their descriptions — for instance, baby carrots (about 50 days) alongside a larger carrot (around 75 days). I do this with peas, giving part of a 20-foot row to Sugar Ann, which produces about 10 days earlier than the taller snap peas that get the rest of the row, then yield longer. I repeat the planting in July for fall harvest.
But even a single variety can do multiple duty. That pea planting, for instance, could be extended to include a section of seeds sown more thickly, intended for harvest at four or five inches high as pea shoots, for salads or stir fries, with the left rest to mature to pods. A portion of a row of kale could be harvested as baby-leaf for salads, and the same with lettuce, with that section resown for more of the extra-fast young version of the crop.
Pay Attention to Heat- and Cold-Tolerance
When you’re seed-shopping, make sure to scan the descriptions for mentions of heat- and cold-tolerance and match the variety to the season you plan to grow it.
Some spinach varieties were bred for improved summer performance, and Batavia or summer crisp lettuces generally stand up well compared to others. With cilantro, there is actually a variety named Slow Bolt that resists the urge.