Control Bolting for Tastier Tender Greens

Leafy Greens

Leafy greens like lettuce are tasty and easy vegetables to grow in your home garden, especially when they’re young and tender. If you want to keep eating delicious, sweet greens for longer, you’ll need to control bolting.


Leafy green vegetables

What Is Bolting?

Bolting is the process of the plant maturing and putting out seed. 

Crops will get taller and put out flowers to form seeds. Bolting is not a bad thing, but premature bolting does mean fewer tasty meals for you. 

Your tender, delicious greens will become more bitter and tough as the plant starts moving its energy to seed production. The plant channels sugars away from the leaves and upward to the flowers. Bitter compounds in the leaves will repel anyone who might want to munch on the leaves - including humans! 

What Causes Bolting?

Many factors cause bolting: 

  • Temperature changes - Plants that are sensitive to heat will bolt at a certain threshold. For example, spinach and cilantro begin to bolt as soon as the temperature hits 80° F. Other plants may start bolting in response to cooler weather, particularly cole crops. Some plants like arugula and bok choi are sensitive to both high and low temps.
  • Day length - For some plants, the temperature isn’t the real trigger, but the length of day and time in the sun. Lettuces that have only 8 hours of light a day can form heads of lettuce even in the heat. 
  • Lack of water or minerals - If plants don’t have enough water or minerals, they’re more likely to bolt. Sensing the stressful environment, they’ll put all their energy into producing seeds for the next generation. 
  • Stress - Rootbound plants, crowded plants, or plants that haven’t been properly hardened off before transplanting can all be subject to premature bolting.
bolted red leaf lettuce

Control Bolting for Tastier Greens

Considering all of these factors, you may already have some ideas on how you can prevent premature bolting. So let’s look at some things you can do to enjoy tender, tasty greens for longer. 

  • Time your plantings - Plant your cool-season crops as early as possible to get the most enjoyment out of these plants before summer’s heat arrives. Planting in late summer for a fall harvest can also yield great results as the summer’s heat and day length is decreasing. 
  • Space your plants - Give your plants the appropriate amount of room to grow. If you’re in doubt, consult your seed packet
  • Reduce stress on your seedlings - Harden your plants off properly for more successful adult plants. Transplant stress may take a while to show up, but it can result in early bolting. 
  • Harvest frequently - Greens taste better at small sizes anyway. So get the most out of your cut-and-come-again crops by harvesting early and often!
  • Container gardening - Plants that are sensitive to heat can best be protected by moving them indoors to a controlled environment once the weather gets hot. 
  • Shield from temperature changes - You can’t control the weather, but there are things you can do to shield your crops. Mulch, increased watering, and row covers can all help to protect plants. 
  • Protect from light - Usually, the more sunlight, the better, but in the case of green leafies, a little shade can be a very good thing. Experiment with shade cloths or planting in a shady spot. 
  • Succession planting - Sometimes, the best you can do is plan for bolting. Planting every two weeks can keep your garden full of tender, tasty greens for longer. 
  • Enrich your soil - Building better soil helps your plants get all the nutrients they need for a longer lifespan. 

Written by Teresa Chandler