LBHS: Companion Planting and Seedling Starting

Hello again, today's post continues the former by detailing another workshop I developed for the students at Luther Burbank High School. As mentioned in the title, this post is about companion planting and seedling starting.

Workshop Details:

30 minutes (10 minute discussion, 20 minute activity)

Workshop Goals:
Teach students how to start plants in a seedling container. Help students gain an appreciation for the complex relationships that exist between plants in a garden.

Required Materials:
- 6-cell seedling containers (1 per student)
- Potting mix
- Perlite
- Seeds (suggestions for varieties listed below)
- Spray bottles
- Permanent Marker
- Masking tape

After explaining to the students that I was going to break them up into teams and teach them to start seedlings for their fall garden, I mentioned that they would also be making teams. After some confused looks,  I used the quiet greenhouse to explain that the teams were made up of plants that work well together, in other words, companions. 

Background information:

Some varieties of plants, such as those in the genus Brassica, have similar nutrient requirements and are susceptible to the same pests. For example, planting Broccoli, Cabbage, Kale, Kholrabi, and Collards (all Brassicas) next to one another can lead to an infestation of Cabbage Moths.  These little white butterflies lay their eggs on the undersides of the Brassica leaves until they hatch into hungry caterpillars that camouflage themselves supremely well. In addition to creating a serious pest problem, the plants can inhibit the growth of each other by fighting over the same kind of nutrients. However, by acknowledging these problems, you organize your garden to reduce pest problems and nutrient deficiencies. 

In other words, due to all the variables that can limit plant germination
outdoors, it is better to seed each hole heavier than you would indoors.

Below is a list of plants that might grow well next to one another. Generally, one plant is an herb with fragrant leaves and will repel flying insects while the other is always an unrelated species:  

- Bok choy and Celery

- Broccoli and Onions
- Cabbage and Dill
- Cauliflower and Rosemary
- Chard and Fava Beans
- Garlic and Kale
- Lettuce and Radish

- Spinach and Strawberries 

Activity Instructions:

First divide the class into groups and assign each group to seed a different combination of companion plants. Once each groups has received their seeds, they will need to fill their seedling containers with potting soil. It helps to have a large container set out, such as a wheelbarrow, so that multiple groups can fill their trays with potting soil at the same time. In addition, a wheelbarrow will give you and easy way to moisten the potting mix before the students put the seeds in their containers. Though moistening the potting mix is not required, by wetting the mix before the students fill their containers, they will be able to easily poke a finger in each cell of their container to the depth of their fingernail. 

Two students show off their seedling trays newly topped with Perlite.

After the students have made a hole in each cell in their container they are to take ONE seed and put it in the hole. After the students have carefully placed the seeds into their containers, they should cover their seeds with a thin layer of perlite to help the soil retain moisture while reducing the chance that fungal gnats will want to lay their eggs in the seedling trays. Fungal gnats prefer dark colored soil because it is indicative of moisture, however the white Perlite can be used to fool these pests... sometimes.

Finally, the students need to label their trays by sticking some masking tape marked with a permanent pen to the side. The students will want to record their name, date seeded, and plant variety. Labeling the trays will help the students identify their variety of seedling and track its growth as it matures into adulthood.