The Cut-and-Come-Again Principle
Most salad greens regrow after harvest if you cut correctly. The key: cut the outer leaves, leaving the growing point (the center "crown") intact. A lettuce plant harvested this way will regrow fully within 2–3 weeks and can be harvested 3–5 times before declining. This is dramatically more productive than pulling whole heads and replanting.
Spring and Fall: Peak Salad Season
Salad greens are cool-season crops — they grow best in 45–65°F temperatures. Spring (soil temperature 40°F and rising) and fall (first frost minus 6–8 weeks) are the prime windows. Direct sow: lettuce, arugula, spinach, mache, claytonia, Asian mustard greens. Transplant: lettuce, kale, Swiss chard. Succession sow every 2–3 weeks to maintain continuous harvest through the season.
Summer: Shade and Heat-Tolerant Varieties
Most lettuce bolts (goes to seed rapidly, becoming bitter) above 75–80°F. Beat summer heat with: (1) a 30–40% shade cloth over beds during the hottest months (drops leaf temperature 8–10°F), (2) heat-tolerant varieties: Jericho romaine, Sierra lettuce, Nevada, Muir, Oakleaf types, and (3) morning harvests before daily heat builds up. Arugula bolts faster than lettuce but is more heat-tolerant; 'Astro' arugula is the most bolt-resistant variety.
For succession planting strategies that keep harvests coming, see our succession planting calendar.
Winter: Indoor and Cold Frame Production
Salad greens are among the most productive winter indoor crops. A grow light setup with trays of lettuce, arugula, and Asian greens can produce fresh salad within reach of the kitchen year-round. Indoor growing requires: full-spectrum LED grow lights (14–16 hours/day), 65–70°F room temperature, and a lightweight growing medium (seed starting mix or coco coir). Outdoors in zones 6+, cold frames and low tunnels keep spinach, mache, and kale producing through most winters.
Variety Selection for Year-Round Production
Spring/fall: Black Seeded Simpson, Buttercrunch, Red Sails lettuce; Bloomsdale spinach; standard arugula. Summer: Jericho romaine, Nevada lettuce; Astro arugula. Fall/overwintering: Spinach varieties with high cold tolerance (Tyee, Space, Olympia); mache; claytonia; kale (Winterbor, Red Russian). Indoor: Any loose-leaf lettuce variety; mild arugula; Mizuna mustard greens.
FAQ
How many times can I harvest cut-and-come-again greens?
3–5 full harvests from lettuce; spinach gives 2–3 strong harvests before declining. Quality degrades over time as plants age — after 4–5 harvests, the flavor typically intensifies (more bitterness in lettuce, more pungency in arugula). Replant when quality drops.
Why does my lettuce taste bitter?
Two main causes: heat stress (above 75°F) and the beginning of bolting. Harvest in the morning, ensure adequate watering, and use shade cloth in summer. If plants are already bolting (central stalk shooting up), harvest immediately and replant.
Can I grow salad greens in a south-facing window without grow lights?
Marginally — window light is rarely sufficient for productive indoor growing in winter (day length and light intensity are both too low). A modest LED grow light ($40–80) dramatically improves yield and quality versus a windowsill alone.
What is the fastest salad green to grow?
Arugula (28 days to first harvest), baby spinach (25–30 days), and radish microgreens (7–10 days) are the fastest. Standard lettuce heads take 45–60 days but can be harvested as baby greens at 25–30 days.
How do I prevent lettuce from bolting?
Keep temperatures below 75°F (shade cloth in summer), water consistently (drought stress accelerates bolting), harvest regularly (frequent harvesting delays bolting), and choose bolt-resistant varieties for your climate.