What is it and how is it made?

An orchard built with recycled materials, to save water, take care of the soil, obtain abundant harvests.

Permaculture is applied to agriculture in many ways , always from the observation of the environment in which we find ourselves and the corresponding planning. One of the design principles is “Getting a Harvest” (we will come back to this in more detail in our permaculture course): we have the possibility and the capacity to decide how to obtain it.

Among the many possibilities the key garden technique it can be a good idea to insert a compact, orderly and productive garden module into the garden. The well-thought-out structure brings several advantages.

Water is a precious resource that we cannot afford to waste, we must at the same time create fertile soil to combat degradation caused by erosion and salinization. The keyhole is an excellent structure for a small functional garden, optimizing these factors. Then we find out better what it is and learn how to do it in 7 simple steps .

Contents [Ocultar]

  • What is the lock garden

    • How come

    • lasagna technique

  • What to grow in the keyhole garden

  • How to Create a Key Garden in 7 Steps

    • 01 – Draw the circle

    • 02 – Build the first tower

    • 03 – Trace the keyhole

    • 04 – Raise the wall

    • 05 – Prepare the lasagna

    • 06 – Make the central basket

    • 07 – Preparing tutors

  • Grow with the Keyhole Garden


What is the lock garden

The lock garden, that is to say » garden lock “, is a technique of creating arable land spread all over the world. It was developed in the mid-1990s in Lesotho, by the Consortium for Food Security and Emergencies in Southern Africa (C-SAFE), but keyhole gardens were built” african style everywhere in the world, for example in Texas and elsewhere in the United States.

But what is the lock garden for all intents and purposes?

It is a raised circular garden about two meters wide, with a keyhole-shaped hole on one side. The hole allows growers to add raw vegetable scraps, gray water and manure to a compost basket in the center of the bed to supply nutrients to the plants.

How come

The keyhole garden can be raised from a minimum of 30 cm to approximately 80 cm from the ground and it has walls built with the available materials: stones, bricks, tiles… The wall not only gives shape and support to the garden, but also helps retain humidity in the growing bed. Stones and bricks act as thermal masses and: during the day they heat up in the sun and at night they give heat to the ground.

In a temperate/subtropical climate like ours, the relationship between temperature and humidity is inversely proportional: when the temperature drops, the humidity increases. As the stones and bricks “cool”, moisture accumulates at their base and between them. This “water” is captured by the plants that benefit from it.

lasagna technique

The Keyhole Garden Bed is constructed in layers: the materials are arranged in “lasagnes” alternating a carbon component (Brown) with a nitrogen component (green). Over time, the soil changes and assumes remarkable fertility.

This usually starts with laying a layer of cardboard boxes at the base of the lock garden. to contain wild plants, and continues with wood, manure, leaves, soil…


The most common materials “Brown” (carbon) are:

  • uninked cardboard;

  • trunks and branches;

  • dry leaves;

  • shredded newspapers;

  • non-resinous sawdust, so it is not a conifer.

On the contrary, “green” materials (nitrogen) are:

  • manure;

  • composting;

  • fresh cut grass;

  • raw kitchen scraps and coffee beans.

We also add some Earth and if you want wood ash or stone flour to integrate the mineral part.

What to Grow in the Keyhole Garden

Keyhole gardens are ideal for intensive sowing a technique in which plants are placed close together maximize production and almost all kinds of vegetables can be grown there.

it’s easier to say what better not to get fat and why:

  • large cucurbits (pumpkin, watermelon, melon) due to obvious space issues.
  • Potatoes because they need to be hit.
  • Growing tomatoes too tall difficult to reach without touching the structure.

Other vegetables? Green leafy vegetables like lettuce, cabbage and spinach, all liliaceae, umbrellas, aromatic herbs… Test to believe!

How to Create a Key Garden in 7 Steps

In May 2019, as a permaculture training activity, we created a keyhole garden in Vivere al naturale, in the beautiful hills of Asti, organized by our friend Mirko. The photos are from the workshop we did to learn how to build this type of garden. Let’s go and see in 7 steps how to build our keyhole. The construction is not difficult and can be done with simple and cheap materials, often even recycled. The time and effort required to build this small raised garden are well spent: such a garden remains fertile over time: the idea is to create a permanent structure.

01 – Draw the circle

after the bird r choose the space in which the lock garden will be erected as flat as possible and respecting the possible shadows of the day (and the seasons), draw a circle to set the diameter.

Normally the size is approx. 200cm it cannot be diverted too much because the entire surface must be accessible from the outside.

to build a rudimentary compass, using two pieces of wood and a string , place a piece of wood in the center and, keeping the rope taut, mark the ground with the other piece of wood. Start laying bricks along the line.

02 – Build the first tower

Create the first brick course , also defining the keyhole. The bricks must be laid in the bubble (or almost).

03 – Trace the keyhole

Pay particular attention to the keyhole. First, make sure you can fit in it comfortably. Direct it towards the cardinal point most protected from the wind: it will prevent the soil from drying out if it is hot or from entering cold air if it is cold.

04 – Raise the wall

Raise the lock garden by overlapping the bricks. In this case, we have planned in a smooth pattern , to create a self-supporting structure. This was mainly due to the amount of bricks we had and the fact that we chose to follow a slight slope, in order to have a drier and wetter area.

05 – Prepare the lasagna

And now it’s time to create the “material lasagna” , to fill the structure. Place the bottom of the boxes, add wood, straw, soil, fertilizer… Always alternating green and brown, as already mentioned.

06 – Make the central basket

Create the central compost basket. In this case we use rods connected by fabric, but it can also be done with plastic netting or chicken netting.

07 – Preparing tutors

Add construction ribs and cross them. Top with tomatoes and cucumbers. Start transplanting the seedlings, choosing the best places to place them. Remember how the shadows move during the day (and during the seasons). These are the classic permanent keepers that are also used in the Synergy Garden palettes.

Grow with the Keyhole Garden

At this point, our Keyhole garden is Ready to go . Then, the first crops must be sown or transplanted. An excellent idea, again with the aim of saving water and preserving fertility, is lots of straw mulch .

The soil prepared in the lasagna has a great initial richness, which will then be fed over time through the central composting basket. It’s the real fulcrum : It will gradually fill with organic waste which, once decomposed, becomes fertile compost and enriches the surrounding soil. Turning waste into a resource has obvious ecological value.

Even the degrading mulch provides a supply of organic matter, all of which allows the Keyhole Garten last years without loss of productivity.

The lock garden on August 10, three months after its creation.

With Mirko Roagna from Vivere al Naturale, satisfied with the work done.

Leave a Comment