Everything you need to know to grow lettuce

Red sails lettuce and petunias

Wednesday, April 3, 2024

Spring is prime time for salads!  Lettuce is its sweetest and most productive in spring and fall.  Lettuce loves cool temperatures, moisture and lots of nitrogen.  It is a super easy "vegetable" to grow from seed, too, and it self seeds.

When the hot weather sets in, lettuce will go from sweet and docile to bolting and bitter in a week.  For summer harvests, chose varieties that are heat resistant like Summer Crisp, Red Sails, Rouge d’Hiver, Freckles Romaine, Summertime Crisphead, Tomahawk, Butter King, and Loma French Crisp.

Bolt-free, sweet summer lettuces

You can buy many different lettuce plants from nurseries or big box stores this time of year or to keep yourself in lettuce all summer, practice succession planting and sow seed every 2-3 weeks.  Lettuce is super easy to grow from seed and there are so many varieties to choose from seeds.  I simply just scatter seeds on top of the soil and pat down either in the garden bed or pot.  Keep moist and you will have lettuce seedlings within a week.

Outdoor seed starting tips

Lettuce and all greens love nitrogen just like your lawn does.  We donate our nitrogen rich coffee grounds to our greens and garden beds.  I also use a liquid fertilizer (guano and sea kelp) or other organic fertilizer monthly.  

It is important to keep the lettuce from drying out.  They need consistent moisture.  It is when lettuce is stressed, either through hot temps or drying out, that they turn bitter and bolt.  This is one of the reasons that the Earthbox is such a good pot to grow lettuce.  It has a water reservoir in the bottom so weekly watering keeps the soil moist even in the hottest weather.  Any self-watering pot will work this way, even one you make yourself or buy a kit to transform a favorite pot into a self watering container.

Lettuce in an Earthbox, self watering pot

Bolting is simply when a stalk arises from the middle of the lettuce plant.  It then flowers and sets seed.  When the seeds start to dry, cut off the stalk and remove the seeds.  I put my seeds in a ziplock and store in the frig.  The seeds stay viable for 2-3 years this way.  Save the seeds from your favorites and re-sow to keep yourself in free, tasty lettuce all season long.  You can also let the seeds fall where they may and you will get volunteer lettuce plants throughout your garden.  

Bolted Red Sails lettuce-cool looking, eh?

Lettuce does well right through fall frost into winter.  Choose cold tolerant varieties for spring and fall Fall and winter greens and heat tolerant varieties to sow in late spring and summer.  One thing to remember is that lettuce seed does not germinate well above 75 degrees so you may have to move your seed starting to the shade or indoors in the dog days of late summer. 

Protection from the afternoon sun helps in lengthening the time before your lettuce bolts.  There are few techniques you can use.  Grow lettuce interspersed with taller veggies to give them shade protection, plant next to a wall that provides afternoon shade, cover with a shade cloth to keep them cooler or grow on the north side of your house.  If growing in a pot, it is easy to just move the pot to a shadier, cooler spot when the temps start to rise.

Harvesting frequently also helps keep the lettuce from bolting.  Harvest the outer leaves consistently and the plant will continue to produce more inner leaves.  I harvest from the same plants for a couple of months this way.

Some, like the Marvel of Four Seasons and Red Sails, stay sweet even when they have bolted.  Give the bolted lettuces a taste to see if it is time to let them go to seed and yank them out to make room for another crop.

I like to grow heat tolerant greens during the summer in addition to lettuces to keep the summer salads going.  

Keep salads going all summer long