Integrate rather than segregate

The old proverb: many hands make light work

Holmgren gives this principle the saying "many hands make light work". Shared among many, a heavy job becomes easy. The proverb is usually heard among people, at a harvest, when a barn is raised or on a community working day, and the principle's website collects exactly such examples, from a school's hen run to a neighbourhood food stall.

In a garden the many hands belong to plants, animals, fungi and microbes. No single member of a plant guild has to do everything, because each does a small part: one fixes nitrogen, one brings up minerals from deep soil, one covers the ground, one draws in pollinators. The gardener's work becomes lighter in the same measure in which these hands are put to use.

How it looks in nature

Nature is full of partnerships so close that the partners can hardly be told apart. A lichen looks like a single organism, yet in 1867 the Swiss botanist Simon Schwendener proposed that it is a fungus living together with an alga, a view that took decades to be accepted. Today we know that the partner can also be a cyanobacterium, and in 2016 Toby Spribille and colleagues found a third partner, a yeast, in the outer layer of many large lichens. Together these partners settle on bare rock that none of them could hold alone.

Below ground, most land plants live with mycorrhizal fungi, which reach water and phosphorus far beyond the roots and receive sugars in return. The page on mycorrhiza tells this story, including the open debate about how much plants exchange through shared fungal networks; a review by Justine Karst and colleagues in 2023 found the field evidence weaker than often claimed. Legumes house rhizobia in their root nodules, bacteria that turn nitrogen from the air into a form plants can use.

Farmers learned from such partnerships long ago. In the Three Sisters of the Americas, maize, beans and squash grown together, the maize gives the beans a pole to climb, the beans bring nitrogen into the bed through their root bacteria and the broad squash leaves shade the soil. Around the Mediterranean, the wood pastures of the Iberian dehesa and montado combine oaks, pasture and grazing animals on the same land.

Where the principle works in the TerraWiki

• A plant guild gathers companions around one central element, so that each member takes over a job the gardener would otherwise have to do.
• Polyculture grows many species on the same ground at the same time and spreads both yield and risk.
• Agroforestry brings trees back onto farmland instead of keeping field and forest apart.
• A silvopastoral system joins trees, pasture and grazing animals on one area, as the farm of Herdade do Freixo do Meio does in the Portuguese montado.
• Nurse trees and ecological facilitation show how one plant makes room for the next with shade, shelter and better soil.
• Nitrogen-fixing plants feed their neighbours when their leaves fall or their branches are cut.
• Cycle thinking shows why loops only close where elements are near each other and connected.

At Sa Medada

Sa Medada is a slope in Jerzu, in Ogliastra on the east side of Sardinia, with mild winters and a dry season that lasts roughly from May to September. An old olive grove covers part of the land, and macchia grows on the steeper slopes. Several nitrogen fixers are already in the ground, among them Tephrosia, the coral tree, Inga edulis and the fava bean, all growing without inoculation. Plants like these feed the soil around them through falling leaves and prunings, which is how nitrogen fixers and fruit trees can become partners rather than mere neighbours. How much they contribute on Sa Medada has not been measured.

Swales are planned; none has been built yet. Project Eden begins with pioneer plants, ground cover and holding water, and we describe the links between them as intentions, not as a finished system.

Along the journey

The seventh principle, Design from patterns to details, sets the large frame; this one fills it with relationships. The ninth, Use small and slow solutions, adds the question of size and pace, because connections grow best in small steps that can be watched.