In the last homeschooling tip, I talked about using mutualistic relationships as a resource in ecologically designed systems. I recommended that your family explore mutualistic relationships by observing how they work in unplanned physical groupings of organisms in nature. Now it’s time to take a look at using mutualistic relationships as a resource in your garden.

Today’s suggested activity is for your family to:

  1. Generate a list of plants you’d like to grow, 
  2. Come up with a verbal description and/or pictorial representation of where you are going to grow them in relationship to each other based on the information I’ve provided below and your own Web research.
  3. Explain your planned arrangement of plants in terms of the relationships among those plants and the plants’ needs for water and sunlight. 

All children that are able to communicate can participate in the first step. Just ask them what their favorite plants to eat and look at are. All children old enough to handle a crayon can participate in representing your design. Older children will be most able to plan and explain the design.

There is a massive amount of information on this topic available on the Internet including plenty of lists of good plants to grow together in guilds. I’ve provided the following information to help get you started thinking about how to use relationships in your garden as a resource. Also remember that experimenting is part of the process. Successful natural plant groups, like the ones you observed in the last activity, arise from natural experiments (AKA evolution through natural selection).

Background Information

Even people who plant in single species rows consider spatial and temporal relationships between their plantings. Relationships like: (a) planting taller plants on the north side of a garden so they don’t shade shorter plants, (b) rotating species to take advantage of their different nutritional needs and contributions, (c) companion planting (i.e., planting two or three species near each other to use their mutualistic relationships as a resource), and (d) planting cover crops to prevent erosion and nutrient leaching and to build soil.

Extended these methods, wholistic garden designers also consider two levels of integration among their plants: guilds and food forests. Guilds are multilayered groups of companion plants usually organized around a large tree. Food forests are groups of multi-layered guilds. Robert Hart’s seven-layer model for guilds and food forests includes:

  • A canopy layer that consists of tall fruit and nut trees.
  • A lower tree layer of dwarf fruit and nut trees.
  • A shrub layer of fruit bushes such as currants and berries.
  • An herbaceous layer of culinary and medicinal herbs, companion plants, and plants that pollinator loves.
  • A ground cover of edible plants that function as a living mulch.
  • A rhizosphere layer that consists of root crops.
  • A vertical layer of vines and climbers.

In addition to including one or more plants at each layer wholistic garden designers consider the various roles each plant plays (or niches each plant occupies). For example, members of the legume and ceanothus families form associations with nitrogen fixing bacteria and, when they are harvested leaving their roots in place, return that nitrogen to the soil. Squashes provide excellent ground cover providing a living mulch that limits evaporation and erosion. And comfrey, artichoke, radishes (especially daikon radishes), mustard, parsnip, root celery, horseradish, docks, parsley, dandelion, turnip, and poppy are all dynamic accumulators that mine nutrients via tap roots and bring those minerals to the surface where they are returned to the soil when the roots of those plants decay (one of the reasons we should almost never harvest plants by pulling their roots out of the ground). Various plants also attract pollinators (e.g., Phacelia, Clarkia, Ceanothus) and some also repel pests (e.g., garlic, basil, mint).

I hope this information is useful for your family’s garden planning. Please post questions and ideas below!

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