Loose-Leaf Lettuce Produces Earlier Crops

By Jim Janke | Jan 09, 2014

We’ve been growing loose-head lettuce varieties like ‘Buttercrunch’ for many years. Plants started from seed indoors in early February go into the garden in late March. Depending on the variety and outdoor temperatures the plants are ready to harvest a month or so later. Seeding every few weeks gives us a continuous supply of fresh lettuce all summer.

Yet on this schedule our first crop isn’t until late April or early May. Loose-leaf lettuce matures faster than head lettuce, and is available in many more colors and textures, so we decided to try it in planters on our deck. Here’s what happened.

In early February (indoors) we scattered seeds on the surface of a seed starting mix, pressed the seeds into the soil, and covered lightly with milled sphagnum moss. We placed the seed flats in a tray of water and covered with clear plastic to maintain high humidity. Seeds germinated in a couple of days, and the plants grew quickly.

Three weeks later seedlings were transplanted into 5 by 17 inch planters filled with a mixture of bagged topsoil and peat based planting mix. Each planter had space for about 30 seedlings. The containers were moved to a protected area of the deck and covered with shade netting for a week or so to acclimatize the young plants to sun and wind. Our harvest started 5 to 6 weeks after seeding, a lot sooner than for loose-head lettuce. Cutting the lettuce with scissors about a half inch from the soil allowed the leaves to re-grow quickly, providing a second harvest a couple of weeks later.

Lessons learned (so far):

  • Seed packets with more than one type of lettuce (like mesclun mixes) haven’t worked for us. The first type to germinate can smother those that sprout later.
  • Seeding inside resulted in much better germination rates because the environment could be controlled more easily. Lettuce seed is viable for a long time; we got excellent germination from seeds 3 or more years old.
  • Placing the planters on a utility cart (our “lettuce factory”) made it easy to move them into shade on warm days or into the house if a hard freeze was predicted.  If the planters contained soil that had been used previously for flowers, a lot of flower seedlings (in our case, petunias) sprouted as the lettuce grew. These “volunteers” were a pain to remove.
  • Planters need to be watered often, and this washes nitrogen out of the soil that is needed for foliage growth. Slow release fertilizers keep nitrogen in the container for a longer time. And using planters with reservoirs minimizes the number of times you have to water, so the nitrogen doesn’t wash out as quickly.
  • Our favorite red-leafed varieties were ‘Red Velvet’ (similar to ‘Red Sails’) and ‘Revolution’. They had excellent flavor and texture, and didn’t turn bitter as quickly as other varieties.
  • Mid-summer crops were poor last year. Either the temperature was too high for the lettuce to grow well, or it rained so often that there wasn’t enough sunshine. Or maybe I re-used the same planter too many times and the soil got compacted. We might skip the May and June seedings this year.

Try growing lettuce and other loose-leaf vegetables like spinach and arugula in containers. You’ll be surprised how easy this is.      

Jim Janke is an Extension Master Gardener Volunteer in Haywood County. For more information call the Haywood County Extension Center at 828-456-3575. © 2014 NC State University.

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