Great Garden Greens
by Gerry Oliver
Lettuce is an ancient crop, dating back at least 6500 years to the time of the Egyptians. By the time of the Greeks, at least three types of lettuce were being grown. Spinach is from a completely different family, and only became widely used after the time of the Romans. The two vegetables however, have similar characteristics and growing requirements. Once the frost has left the ground, we can plant both. They will germinate in soils at temperatures of 35 to 38 F (2 to 3 C).
Both leafy vegetables have reputations as low-calorie, healthy foods. They contain large quantities of Vitamin A, C and iron and thiamin. The amount of iron varies depending on the variety of lettuce, while spinach has higher levels of vitamins than lettuce.
Secrets to Great Greens
Rich soils seem to be the key to growing great leafy greens. Both plants require high levels of nitrogen. For best results, liberally work manure into the soil, prior to planting the seed or transplants.
Garden greens also need a good supply of potassium for maximum production. Potassium speeds their growth, enabling harvest during the cooler growing season as well as producing thick, crispy leaves. A good source of potassium is wood ashes. These should also be incorporated into the soil prior to planting.
Both lettuce and spinach have shallow, fibrous root systems, demanding lots of moisture throughout the growing season. Water thoroughly every three or four days during dry weather.
High nighttime temperatures (above 65F or 18C) and high humidity can sometimes produce browing on the tips of the leaves. Just prior to maturing, some varieties of head lettuce stop producing certain root hairs, which enable calcium uptake from the soil. The plants suffer from calcium deficiency, resulting in that burned look.
In the Garden
Make sure the soil is well prepared. Plant the seed very shallow, (about 1/4 inch/1/2 cm deep). Try mixing a little sand or sugar with the seed for more even sowing rates. Carefully firm the soil over the seed and water well. Germination usually occurs within seven days. Thin and weed the greens as they emerge, to four to six-inch spacing.
Transplants are another way to start your "green patch". These can be started indoors or in a coldframe. Be sure to grow them cool!
Harvest the plants young, when the leaves are tender and crisp. Pull the entire plant up, and remove the roots; those can go in the compost pile. For best results with spinach, plan to use it on the day of harvest. Harvest the leaves of both greens in the early morning while they are crisp.
Why Do They Bolt?
Sometimes, spinach or lettuce plants bolt or become bitter tasting before maturing. "Bolting" is the rapid maturation of the plant, with seeds being produced. With maturation, more milky latex is deposited in the leaves, making them taste bitter. The reasons for these problems lie with warm day temperatures and day lengths of 14 - 16 hours.
Lettuceis very sensitive to long days. Twelve hours per day is the maximum amount of time these plants can tolerate without initiating bolting. To slow down bolting, harvest the oldest leaves regularly.
Which Lettuce Varieties to Grow?
Looseleaf - Varieties mature within 40 - 50 days, but tend to bolt. Red Sails or Red Salad Bowl are very attractive; Simpson Elite and Green Ice are slower to bolt.
Butterhead - Buttercrunch has crispy, crunchy leaves; Esmeralda resists disease and bolting.
Head - Summertime has good tolerance to heat; or the unusual, one-serving sized Mini-Green.
Romaine - Plato is resistant to bolting and tip burn; Parris Island 318 is larger and taller than most.
Great Spinach Varieties
Spinach will mature in 30 - 40 days. Some reliable varieties include: Razzle Dazzle - Grows quickly; sweet, tasty plants Tyee Hybrid- High-yielding; big, thick, juicy, dark green, semi-crinkled leaves.
Correnta - High yields, great nutritional qualities and heat tolerance. Melody - Slightly crinkled leaves which are easy to clean. Longstanding Bloomsdale - An old-time favorite with the most crinkled leaves.