Outdoor and Environmental EducationOutreach Creating an Edible Garden → How to Create an Edible Container Garden

How to Create an Edible Container Garden

Step 1: Select a site

For beginning gardeners, a consultation with a University of Maryland Extension Master Gardener is highly recommended.  Master Gardeners can provide guidance and assistance with the site selection, as well as garden creation and maintenance planning.

General considerations for selecting a site include the following:

  • A courtyard or protected area is the best choice, if available, to minimize vandalism and theft, prevent application of pesticide or herbicide, and minimize animal access (rats, mice, groundhogs, deer, etc.).
  • The site must have adequate sunlight and be fairly level.
  • The site should be easy to access and safe for student movement (provide ADA accessibility).
  • The site must have access to a functioning, outdoor water source
  • The garden containers should be placed outside of NO MOW zones and Forest Conservation Areas, if present on school property
  • Include students in the site choice.
  • Request input from Building Service Manager.
  •  Discuss the proposed site with school principal.  


Important Safety Guidelines include:

  • The garden site cannot impact flow of traffic, obstruct sidewalks, or utilities.
  • The garden site cannot impede emergency exit routes.
  • Important Facility Regulation
  • Container Gardens may not be within fifteen (15) feet of the exterior building walls or air intakes and/or three(3) feet of a fence  


Step 2: Complete and Submit Approval Form

Complete and submit the following items to the Division of Construction. The more complete your form and attachments are, the shorter your project evaluation time will be.

  • Facility Project Request 
  • School site plan with proposed garden location marked (Your school principal can acquire the site plan from the Division of Construction.)
  • Plant list, only if not using plants from recommended list found in Step 3

Timeline: Submit your request to Division of Construction between September 15 and March 31: Six weeks is an average response time. (Requests received after April 1 will not be reviewed until September 15, because summer projects take precedence over new requests.


Step 3: Plan the Garden with Your Students

Student involvement in the garden planning process immediately engages them in the full experience. Here are links to some helpful documents to guide your container gardening experience.


Step 4: Plant the Garden

For details: Factsheet on Container Vegetable Gardening  

  • Mix water into the growing media until it is as wet as a wrung–out sponge
  • Fill your container with the growing media and level it off (don't pack it).
  • Seeds can be planted in straight rows (furrows) or in a pattern. You create a furrow by dragging your finger or a pointed object through the growing media. The furrow should only be about 1/2 in. deep. You can also poke your finger ½ in. deep in the growing and plant a few seeds per hole.
  • Shake some seeds into a folded index card and tap them where you want plants to grow. Or, tap some seeds from the packet into your hand and use your thumb and forefinger to plant the seeds.  The spacing between plants will vary depending on the crop.
  • Many of the crops have dark color seeds making them harder to view against the dark color growing mix.  Some of the lettuce seeds are white making them easier to see. The round seeds tend to bounce so keep the index card close to the growing mix. (NOTE: young children will have difficult time picking up and dropping the seeds at the correct spacing).
  • Cover the seeds about ¼” deep by gently brushing the growing mix from either side of the furrow.  Press down on the growing media so that good contact is made with the seeds.

What should I do with the extra seed?
Carefully re-seal or fold the seed packet.  Keep all seed packets in a protected container indoors where they will be dry and at room temperature. You can increase the life of your leftover seeds by storing them in a small glass jars in a refrigerator or freezer.

When will I see the new seedlings?
Members of the cabbage family (e.g. arugula, kale, mustard, and broccoli) will germinate the fastest (2-4 days).  Lettuces are next (6-10 days).  Spinach, chard, and cilantro will take 7-10 days to germinate.  Germination will be slower when growing media temperature is below 60°F or above 80°F

How long does it take? How big will they get?  

Vegetable plants grown in containers don't get as large or produce as much as the same plants grown in a garden, because they don't have as much growing room above or below the ground. For example- a Swiss chard plant will grow 3 ft. tall and 2 ft. wide when planted 2 ft. apart in an in-ground garden. The same plant will grow 1/3 that size when planted 1 ft. apart in an 8-in. deep container; and only 6-8 in. tall when planted 2 in. apart in a 4-in. deep container. But container-grown plants may germinate and grow more quickly. Managing expectations is important to avoid disappointments.  


Salad greens will grow:  

  • 2-3 inches in height in 12-24 days (micro-greens)
  • 4-6 inches in height in 25-40 days (baby greens)
  • 7-10 inches in height in 40-60 days (mature size)

This all depends on…  

  • the crop-  lettuce and arugula will grow faster and taller than spinach or chard
  • spacing- allowing more space between plants will allow them to grow larger
  • time of the season- fall salad greens planted in September will germinate and grow faster than the same crops planted in March.
  • weather conditions- warm weather will speed up growth; cold, wet weather could reduce growth.


It's easy to sow the seeds too thickly. In that case, you simply remove excess seedlings to achieve the 1-2 in. spacing.  It's OK to increase the plant spacing.  This will give you fewer, larger plants. Removing excess plants is called “thinning.” You can gently pull the excess plants out by hand or cut them at the surface with scissors.  They can be composted, added to a salad that evening, or dropped on the ground.



Step 5: Maintain the Garden

Create a maintenance plan for tasks- watering, fertilizing, and checking plant progress. This can be done by students, parents, teachers, para-educators, building service staff, or after-school clubs.


Should I Fertilize?  

Soilless growing media contain a small amount of fertilizer that will provide some nutrients to your plants for 4-6 weeks, depending on weather conditions, planting density, and other factors. Add fertilizer to your containers prior to planting to ensure strong, sustained growth. This is especially important for the salad greens which are “heavy feeders”. In most cases the one application will be enough. 

Use a fertilizer that contains nitrogen, phosphorous, and potassium. Always follow label directions. If the growing mix used is 50% compost, reduce fertilizer amount by ½, and don't fertilize until plants are up and growing. To prevent leaf burn, wash off any fertilizer that lands on leaves and don't apply fertilizer when leaves are wet. The following fertilizers will work fine: alfalfa meal, cottonseed meal, organic garden fertilizers, liquid fertilizers, and Osmocote (slow-release nutrients).


How much watering will I have to do?
After sowing seed you must keep the growing media moist.  You probably will not need to water every day until after seedlings emerge.  Then you'll need to water daily using a watering can or watering nozzle (e.g. “water breaker) attached to a hose. Water gently until the growing media is uniformly moist.


Accelerate plant growth with a floating row cover?  

All of the recommended crops will germinate and grow under typical spring and fall conditions in MD, and all except snap beans can tolerate a light frost. Covering your plants with a floating row cover will speed growth and protect plants from frosts, insect pests, and wildlife. They are made from spun-bonded polypropylene and will last several years. Prices are 3-5 cents per square foot of material and you cut them to the desired sizes with scissors. A large number of mail order seed and garden supply companies carry various brands and types of floating row covers. Check first with local stores.


What's the best way to harvest salad greens?
The “cut-and-come-again” harvesting method is very efficient. Use scissors to cut all plants close to the growing mix. The plants will produce new leaves from the base and can be harvested a second time in 3-4 weeks. Sometimes it is possible to get a third cutting.  An alternative harvesting method is to thin plants so they are spaced 4-6 inches apart and harvest outer leaves or entire plants.



Step 6: Clean Up the Garden

The 20 recommended crops produce a first harvest 25 days (e.g. lettuce) to 55 days (e.g. beans) after planting. This means you plant each container one time for the spring season and one time for the fall season. At the end of the harvest just pull up the plants and compost them.

Dump the growing media in heavy plastic bags and store them and the empty containers in a suitable location. Containers can be left in place but animals may disturb the growing media. The growing media can be re-used the following year. Freshen it up with some new growing media and add fertilizer to make up for the loss of nutrients over the growing season.


Salad Table Instructional Videos: 

Video 1: planting, fertilizing, watering   

Video 2: thinning and harvesting