Leafy greens such as lettuce and spinach are one of the first things harvested from a vegetable garden. These cool season crops which thrive when the average daily temperature is between 60 to 70 degrees Fahrenheit cannot withstand hot summer days. High temperatures cause plants to bolt, or produce a seed-stalk. In addition, leaves may become bitter and have a poorer texture.
The hotter daytime temperature will soon cause most of our lettuce, spinach and radishes to become bitter and bolt. One way to extend the growing season for leafy greens is to plant in a Salad Table™. Advantages of growing greens in a Salad Table™ include extending the growing season greens, gardening by the back door, tables are portable and can be moved to a shadier location during the heat of the summer. Typically air temperatures are slightly cooler in the shade. Also to prevent bolting, keep soil moisture consistent.
This spring, I am using a Salad Table™ to grow spring greens. While I used the original concept, the table I have is modified to two feet tall and an 21 inch square. Since I have these structures on my deck, I find that I am eating more lettuce and spinach. For design plans and information on growing in Salad Tables™ visit University of Maryland Extension, Salad Tables™ at https://extension.umd.edu/hgic/topics/salad-tables%E2%84%A2
Leaf lettuce (looseleaf), butterhead (Bibb) and romaine (cos) lettuce can be planted for a spring crop when the soil is dry enough to rake the surface. For a fall crop, plant seed in late August. Water is essential for seed germination and establishment of seedlings. Plant fresh seeds 1/4 to 1/2 inch deep.
The first planting of spinach can be made as soon as the soil is prepared in the spring. For a fall crop, plant seed in late August. Plant seeds 1/2 inch deep. If the soil was prepared in the fall, seeds can be broadcast over frozen ground or snow cover in late winter and they will germinate as the soil thaws. A uniform supply of moisture is essential to produce rapid leaf development.
Lettuce and spinach leaves may be cut when they are large enough to use. Leaf lettuce reaches maximum size in 40 to 60 days. Spinach can be harvested about 37 to 45 days after planting.
Spinach and leaf lettuce can be harvested two different ways. Remove the outer leaves when they are 3 to 6 inches long and allow younger leaves to develop. The other option is to harvest the whole plant when at least five or six leaves have formed. Just before serving, rinse greens in cold water. Lettuce and spinach should be eaten while fresh and crisp.
For more information on recommended varieties, growing and harvesting lettuce and spinach visit the University of Illinois Extension “Watch Your Garden Grow” website at https://web.extension.illinois.edu/veggies/