Growing Container Safe Salad Greens

by M. Bunning, F. Stonaker and A. Card 1 (3/2010)

Quick Facts…

  • Growing your own salad greens can provide a source of fresh, flavorful leafy vegetables with the added benefit of being able to try interesting varieties.
  • Salad greens are nutrient rich, generally easy to grow, and may be used in a variety of ways.
  • Following these practical tips can help you enjoy a supply of fresh home-grown salad greens.
Bowl of salad greens on wooden table.

Benefits of Salad Bowl Gardening

Growing your own salad greens gives you the chance to have fresh, flavorful leafy vegetables and an opportunity to try some of the interesting varieties that are available. Often, the most colorful greens are higher in nutrients.

You will be able to harvest your first crop in just a few short weeks, using the small tender leaves that are often not available to buy. These micro-greens are the mix of choice for gourmet salads. Leafy greens also make a flavorful addition to sandwiches or wraps.

One of the joys of salad gardening is being able to plant once but harvest multiple times. Leafy vegetables can often be cut down almost to ground level and will re-grow additional leaves for your next harvest. You should be able to enjoy three or more harvests from each planting.

Salad mixes can be planted much closer together than other vegetables since they will not be maturing into full-sized plants. To have a season-long supply of greens, you may want to stagger your plantings to maintain a continuous supply of harvestable leafy greens – providing a salad source from early spring until fall.

Salad bowl gardening doesn’t require much effort or space – a deep tray, a few clay pots, or a 3-by-3 foot plot of ground in a sunny location can supply a bunch of salad greens. Growing in containers can help reduce problems with insects, soilborne diseases and poor soil conditions. Plus, your portable garden can be moved in order to catch more sun or shade as needed or to avoid extreme weather conditions.

Leafy greens are ideal for the cool temperatures and short seasons of Colorado because they can be eaten at any stage of maturity and grown in portable containers.

How to Grow a Salad Bowl Garden

Container. A tray, pot, or window box that is at least 18 inches across and 6 to 12 inches deep is a good choice. Deeper pots allow more room for roots and keep the soil from drying out as quickly.

The container can be made of clay, plastic or wood, but needs to have drainage holes in the bottom – you may want to use a self-watering container or position one tray inside another to prevent leaks. Fill the container with a good quality potting mixture; some mixes are formulated to retain moisture that can be beneficial in Colorado’s dry climate. If containers are placed outside, plants and soil will be subject to more water loss and will need a larger reservoir of soil moisture. Over time, mineral deposits and other debris can accumulate on the container and may harbor disease organisms and cause problems for plants.

To disinfect plant containers, use a stiff brush to remove soil and mineral deposits, soak in a solution of one part household bleach to nine parts water for at least 10 minutes, and rinse well with water.

Seeds. Greens grow quickly so they can start from seeds rather than transplants. In addition to being more economical, growing from seeds offers the opportunity to choose from the wide variety of different types of leafy greens. Some of the choices available for salad mixes are lettuce, mustard greens, arugula, cress, mizuna, chervil, endive, mache, Chinese cabbage, tatsoi, escarole, garden cress, kale, and Swiss chard.

Often several brightly colored varieties come as a mix in one packet. “Mesclun” means mix and usually includes arugula, lettuce, endive and chervil. Many salad mixes include greens, like arugula, that have a tangy taste and add unique flavor. Red and dark green types generally are higher in nutrients and antioxidants. Some varieties are identified as heat tolerant and these may be good choices for container gardening.

Care. Before planting, thoroughly moisten the potting mix but not to the point of soaking wet. It’s a good idea to do this a few hours before planting. Water gently after planting, keeping the soil surface moist until plants emerge. Five or six hours of sun a day is recommended but many types of salad greens can get by with less and can even be grown in partial sunlight or shade. During the hottest part of the day, lettuce will need to have some shade. Remember leafy greens are cool season crops and prefer temperatures below 85F; in fact many leafy greens are cold hardy and can survive light frosts.

Planting. The seeds can be sown densely with about ½ inch between seeds. Scatter them onto your freshly prepared soil and sprinkle with a ¼ inch of potting soil. Keep the soil uniformly moist but not soggy. After germination assess soil moisture by looking at the color and contraction of the potting mix from the sides of the container. As it dries it will look lighter and pull away from the sides of the container. Another method for assessing moisture is to feel the weight of the container when it is wet. As it dries, it will feel lighter. If you are going to be away for a few days, ask a friend to water daily because drying out can cause major setbacks to young plants.

Feeding. Apply small amounts of fertilizer (half-strength) when the plants are 4 to 6 inches tall and every two weeks after that. Start a regular fertilization program, follow the directions on the package. For the best results, maintain a regular watering and fertilizing schedule.

Harvesting. You can start harvesting after only a few weeks. Just cut what you need and leave the other plants to grow, prolonging your harvest. You can start thinning as soon as the plants are a few inches tall – the remaining plants will fill in the empty spaces. Use a pair of scissors or shears to cut the plants after they reach a height of four to six inches, leaving behind about an inch of stubble to resume growth. Lettuce can be picked leaf by leaf almost from the time the first one emerges. If the lettuce starts to “bolt” (sends up a stalk and goes to seed) the leaves tend to be bitter. Remove any plants that start to bolt to enjoy the best flavors that your garden can provide.

Storage and Preparation. Always refrigerate salad greens at 35F to 40F and wash thoroughly under running water right before using.

Resources & References

Cleaning and Disinfecting Plant Containers. Iowa State University Extension, Horticulture & Home Pest News.

9.373. Health Benefits and Safe Handling of Salad Greens, See for more fact sheets on gardening and food safety.

1M. Bunning, Colorado State University, food science and human nutrition, Extension food safety specialist; F. Stonaker, assistant professor, horticulture and landscape architecture; A. Card, Extension agent, Boulder County. 3/2010.

Colorado State University, U.S. Department of Agriculture, and Colorado counties cooperating. CSU Extension programs are available to all without discrimination. No endorsement of products mentioned is intended nor is criticism implied of products not mentioned.