When to plant lettuce in Burns, OR

Getting seeds to sprout

Lettuce sprouts in soil as cool as 35 to 40°F and does best around 75°F. Many varieties also need some light to germinate, so sow seeds no more than about a quarter inch deep and keep the surface moist.

In summer, soil above about 80°F can make lettuce seeds go dormant, and they simply won't come up. To sow in July or August, water the bed to cool it, sow in the evening, shade the row with a board or shade cloth until seeds sprout, or start seeds indoors where it's cooler.

Bolting and bitterness

Lettuce bolts (sends up a flower stalk) in response to heat and long days. As it does, the leaves fill with a milky sap containing bitter compounds. Once the center starts to stretch up, the bitterness can't be reversed.

To delay it, grow slow-bolting varieties for summer, give afternoon shade, keep the soil moist, and sow small batches every two to three weeks so there's always a young planting coming along.

Soil and water

Lettuce has shallow roots and grows fast, so it needs steady moisture and fertile soil with a pH of about 6.0 to 7.0. Mix in compost before planting. Dry spells make leaves tough and bitter, and uneven watering can cause tipburn, the brown, crispy leaf edges caused by a short supply of calcium during fast growth.

Cold tolerance

Most lettuces handle light frost, and hardy types like Winter Density and Arctic King take nights into the mid-20s. West of the Cascades, fall-sown lettuce under a cold frame or row cover can keep going through much of winter. Leaves that freeze solid will thaw fine if left alone; don't pick them while frozen.

Harvest and storage

Pick in the morning, when leaves are fully hydrated and crisp. Lettuce keeps best right above freezing with high humidity, so store it in a bag or container in the coldest part of the fridge, where it lasts one to two weeks.