{"slug":"lettuce-succession","primaryCrop":"lettuce-leaf","category":"continuous-harvest","chains":[{"phase":1,"crop":"lettuce-leaf","sowMethod":"direct_sow","intervalWeeks":2,"startRelativeToFrost":-28,"endRelativeToFrost":42,"climateNotes":{"maritime":"Season extends comfortably through June; keep sowing every 2 weeks until daytime highs cross 75F.","humid_subtropical":"Bolts by mid-May; stop spring sowings around day +21 and switch to phase 2 early.","arid":"Shade cloth (30 percent) extends the spring window by 2-3 weeks into early summer."},"notes":"Choose loose-leaf and Batavian types for the most heat tolerance late in the spring window."},{"phase":2,"crop":"malabar-spinach","sowMethod":"transplant","intervalWeeks":null,"startRelativeToFrost":42,"endRelativeToFrost":120,"notes":"Heat-tolerant climbing substitute when lettuce bolts; one planting on a trellis fills the summer salad gap."},{"phase":3,"crop":"lettuce-leaf","sowMethod":"direct_sow","intervalWeeks":2,"startRelativeToFrost":120,"endRelativeToFrost":180,"climateNotes":{"maritime":"Carries into November under a low tunnel.","continental":"Stop sowings 30 days before first fall frost; cold-hardy varieties (Winter Density, Rouge d'Hiver) extend by 2 weeks under row cover."},"notes":"Fall succession; pick cold-hardy varieties as the window closes."}],"source":"Johnny's Selected Seeds succession guide; Cornell Cooperative Extension"}