A raised garden it is an excellent solution for growing vegetables on the terrace or in a courtyard with a concrete floor. It is also excellent for those who have problems bending over and for those who want an undemanding garden in terms of maintenance (I am referring above all to weeds ...). A raised garden however it must be well built to work well.
Construction of a raised vegetable garden
First decide the height at which you want to work. If the goal is to stoop as little as possible, the topsoil layer should be roughly at waist level. In this case you can use wooden pallets as a support for the boxes. Otherwise the vegetable garden can rest on the ground and the processing layer will be about 50 cm, which is already excellent.
To build the caissons. The most suitable wood to make the caissons of a raised garden it is cedar, but if you don't have one you can use another one: the important thing is that it is weatherproof and not very deformable. For the thickness of the panels 4 cm is good, which is not a little and possibly you can do a little less, while for the length I recommend a 120 × 120 cm. A box must be neither too small nor too large and the square shape is the most comfortable (to increase the cultivated area, just put several boxes together). 60 cm is fine for the height. So for 1 raised vegetable box you need:
- 4 cedar wood panels 120x60x4;
- 8 joiner's hinges (at least) to square the panels;
- 2 cm wood screws and nails (a handful).
To build the cultivation layer. Once you have built your wooden box, the other materials you need are:
- anti-mole metal mesh (but only if the box rests on the ground);
- resistant plastic sheet;
- expanded clay;
- mulch material.
The anti-mole net must be nailed under but if yours raised garden it's on the terrace obviously you don't need it. Then the plastic sheet that will act as a base and covered with a layer of expanded clay must be hooked, which in reality is not essential but promotes drainage. Finally, the soil must be laid, then surmounted by the mulch layer. For the soil, calculate a thickness that brings the cultivable layer about 10 cm from the top edge.
Wood chips, bark and dry leaves can be used for mulching. Keep in mind that the mulch layer performs a number of functions: it contains the growth of weeds, maintains soil moisture, protects the soil from erosion, prevents the formation of the 'surface crust' and raises the temperature of the soil.
Raised vegetable garden in permaculture. If you opt for permaculture, the construction of a raised vegetable garden does not require a layer of plastic on the bottom or even expanded clay. In place of this you will put a layer of seasoned wood logs, which will guarantee the fertilization of the soil above for 6-7 years, surmounted by a layer of branches and leaves covered with mature manure. Above all: topsoil and mulch. Obviously, a raised permaculture vegetable garden is suitable for a corner of the garden (perhaps to solve the problem of poor soil quality) and less so if we are talking about a terrace or a courtyard.
Read also our new article: How to build a raised vegetable garden
Photo of raised gardens
To get useful ideas and see some beautiful creations, I refer you to our selection of photos dedicated to the raised gardens.