The vegetable garden in the caisson: how to build it

Making the vegetable garden in the box allows you to have excellent results and work comfortably. It is a question of creating raised flower beds, but unlike cultivation in trunks or raised rows, in this case a real container is built that acts as an external wall to the cultivated part. This allows you to significantly raise the level of cultivation and keep the spaces tidy.

To indicate this technique we can also use the terms "Formwork" or "formwork", borrowed from construction, where they indicate the wooden containment structure that is used to lay foundations or raise walls. The principle is the same: an external structure contains the land that is cultivated.

The fact that the containment divides the spaces makes this system optimal for gardens in the garden, delimiting lawn crops and ornamental flower beds. This is a system in use for too cultivate the terraces, while the fact that it is raised makes it ideal for working with people with disabilities and is in fact used in social gardens.

The container can be made of various materials and consists exclusively of the side walls, while the bottom of the formwork can remain freely in contact with the ground, in order to allow the water to drain properly.

Why make the formwork

Creating a raised box vegetable garden involves a fair amount of work in the planting phase, but once it is put in place it allows several advantages, which we discover below.

  • Comfort in work.The ground is raised and this allows you to work more comfortably, without having to bend down. This feature is particularly useful in social gardens: people with disabilities, in wheelchairs or with other physical difficulties to prevent movement may have the ability to reach the garden beds more easily.
  • Better drainage. The rise allows for better water drainage, avoiding excessive humidity that can cause rot and disease.
  • Fewer weeds. the raised position makes the garden more difficult to reach from the seeds of the various herbs, while the side barriers, if buried for about ten centimeters, separate the cultivated area from the outside and prevent the roots of spontaneous plants from approaching the vegetables.
  • Better aesthetic impact. The formwork vegetable garden remains more tidy aesthetically, it lends itself to situations of vegetable garden that also have an ornamental value.
  • An easy-to-cover garden. If the edges of the formwork are left at least 30 cm higher than the cultivated land, it will be easy to cover with non-woven fabric or with shading nets depending on the season. In this way, horticultural plants can be preserved as needed from winter cold or too much summer sun.
  • Choose the substrate. Where the soil is not suitable for cultivation due to its characteristics or because it is very impoverished, the formwork can be filled with suitable soil, choosing a suitable substrate, and cultivating anyway. The same system applies to cultivation on terraces or on cemented open spaces.

The vegetable garden in a caisson is an excellent idea if you suspect that your land is contaminated by pollution.

How to build a raised garden in formwork

The choice of material. The formwork necessarily needs side walls that support the soil and allow it to be raised. What are the outer walls of the caisson can be built using different materials. The most ecological and natural choice would be to use dry stone or wood. Dry stone wall is quite long to build, while wood is the cheapest and simplest material, but it has the defect of easily deteriorating due to humidity. The alternatives are the use of containment in cemented stone, metal or plastic. It is advisable to avoid plastic both for the cost and for the ecological impact. The metal must be steel or galvanized iron to avoid rusting and this is also very expensive. In any case, it is necessary to choose materials not treated with chemical substances that can contaminate the earth. In the photo, the formwork was made by Geosism & Nature using panels of recycled wood flakes, glued with fish-based glues and therefore free of chemical additives.

How to support the walls. The way of construction depends on the material that is used. Assuming the construction of a wooden box, poles must be planted in the ground to nail the panels to. The poles must be planted at least 30 centimeters, the panels instead can be buried at a depth of about 10 centimeters.

Dimensions of the box

The formwork must be of such dimensions that it is always possible to access the land to be cultivated by standing in the walkways: the cultivated soil should never be walked on, so that it remains soft. For this reason, raised flower beds must not be wider than one and a half meters, the length can be decided at will. The height of the formwork can be done as you wish, to work in the best possible way we recommend a rise of 50/60 centimeters.

The walkways

A very important thing is to correctly set the walkways between the garden boxes: they are the spaces in which the cultivator moves and must be of sufficient size for comfortable passage. If you want to move with a wheelbarrow, you must leave an adequate size, it can be very useful for transporting fertilizers, seeds and tools without effort. Whoever designs a social garden for the disabled must pay particular attention and leave very wide walkways, which allow those in wheelchairs to pass and turn around.

Mulching of walkways. The walkways can be mulched, to work dry and avoid having to cut the grass between the boxes. Paths should not be paved entirely, as the soil should not be waterproofed. Better to use mulch sheets that allow water to pass through, even if they are damaged in the long run. An interesting alternative conceived by Geosism & Nature is the reuse of disused rollers used in gravel and sand crushers: these are long strips of material that can be found free of charge.

To know more

This article was written with the important technical contribution of Geosism & Nature, for more information you can contact dr. Simone Barani ([email protected] or 348 8219198). On the Geosism & Nature website you will find a more extensive and detailed article on formwork gardens, with interesting insights into the choice of substrate and working the soil of the garden in the formwork.

Article by Matteo Cereda, written with the technical advice of dr. Simone Barani, geologist.

Video: How to Fill Raised Vegetable Garden Beds and SAVE Money (October 2021).