Massifs surélevés et bacs de plantation
Des bacs de culture qui durent plus longtemps que le jardin lui-même
Le bois pourrit, le métal rouille, et les deux finissent par s'remplacer. Les jardinières PolyBrick® s'assemblent en quelques minutes à partir de polymère recyclé à 100 %, et remplissent encore leur rôle vingt ans plus tard.
Pourquoi PolyBrick est adapté à cet usage
Un bac de culture subit les conditions les plus sévères qui soient pour un matériau de construction : en permanence humide côté intérieur, exposé aux intempéries côté extérieur, et en contact avec une terre en décomposition active.
Le bois perd ce combat. Même traité, il se dégrade depuis la face intérieure, là où on ne le voit pas, et le premier signe visible est généralement un mur qui bombe sous le poids de la terre gorgée d'eau. L'acier Corten et l'acier galvanisé ont de l'allure, mais rouillent à la base, surchauffent en été et coûtent nettement plus cher. Les blocs de béton fonctionnent, mais nécessitent du mortier et un maçon dès qu'on sort d'un tracé rectiligne.
PolyBrick n'est affecté par rien de tout cela. Il ne pourrit pas, ne rouille pas, ne se fend pas, ne se rétracte pas et ne se déforme pas. Le matériau est inerte et ne migre pas dans la terre de culture. Il est résistant aux UV : il ne devient pas cassant et ne se décolore pas au soleil.
La pose est également rapide. Les blocs s'emboîtent par simple pression, sans outil, sans mortier et sans compétence particulière en construction : si vous savez empiler des blocs, vous savez le construire.
Applications adaptées
- Potagers et carrés de salades
- Massifs ornementaux et jardinières
- Carrés d'herbes aromatiques et jardins potagers
- Parcelles de jardins familiaux
- Bacs accessibles et bacs à hauteur de travail
- Jardins scolaires et partagés
- Jardinières de terrasse et de cour
- Fosses d'arbres et entourages d'arbustes
Caractéristiques principales
| Assemblage | Emboîtement par pression. Sans outil, sans mortier, sans fixation |
| Forme | Modulaire : les bacs peuvent être de toute longueur, en L, en gradins ou en terrasses |
| Base | Plane et stable. Ouvert sur le sol naturel ou posé sur une surface dure existante |
| Contact avec la terre | Inerte. Ne migre pas dans la terre de culture |
| Matériau | Polypropylène recyclé à 100 %, résistant aux UV, fabriqué dans l'UE à partir de polymères recyclés |
| Compression | Testé à 150 tonnes/m² sous charge statique fixe |
| Durée de service | 25 ans sous garantie |
| Entretien | Aucun. Ni traitement, ni lasure, ni doublage, ni remplacement |
Choisir la bonne hauteur
La hauteur du bac détermine le confort d'utilisation au quotidien. Mieux vaut y réfléchir avant de commander plutôt qu'après.
Faible, un ou deux rangs, convient aux plantations ornementales, aux cultures de salade et partout où l'on cherche avant tout à délimiter l'espace et à disposer d'un peu de profondeur de terre.
Hauteur intermédiaire : c'est le potager pratique par excellence. Profondeur de terre suffisante pour la plupart des cultures, sol qui se réchauffe tôt au printemps, et hauteur idéale pour s'asseoir sur le bord pendant le travail.
Hauteur de travail debout : cela change qui peut jardiner. Plus besoin de s'agenouiller ni de se pencher, et accessible depuis un fauteuil roulant ou un tabouret. Pour toute personne à mobilité réduite utilisant le jardin, c'est une solution déterminante — et c'est la modification que les gens regrettent le plus souvent de ne pas avoir faite dès le départ. Veillez à limiter la largeur pour que le centre reste accessible depuis un côté.
N'oubliez pas que la terre est lourde et qu'un bac profond en contient une grande quantité. Pour tout bac de hauteur inhabituelle, communiquez-nous les dimensions et nous vous conseillerons en conséquence.
How it goes together
- Choose the position: most vegetables want sun, and a bed against a fence is only reachable from one side, so allow for that in the width.
- Clear and level the ground where the bed will sit. It does not need to be a construction-grade base, but it does need to be flat and firm, because the first course sets everything above it.
- Lay the first course and check it with a spirit level in both directions. On a slight slope, dig into the high side rather than packing up the low side.
- Build up in courses, pushing blocks together and staggering the joints between courses. A tap with a rubber mallet seats them fully.
- Cap the top course for a clean finish and a comfortable edge to sit on.
- Fill: coarse material at the base if the bed is deep, then a good topsoil and compost mix. Fill in stages and let it settle rather than filling to the brim in one go.
Filling a deep bed economically
Buying enough topsoil to fill a tall bed to the top is expensive and unnecessary, because most crops never root that deep.
Fill the bottom third with coarse woody material, turf turned upside down, or clean rubble if drainage is the priority. It breaks down slowly, feeds the bed from below, and saves a great deal of bought soil. Then good topsoil and compost above it, which is the layer the plants actually use.
Expect the level to drop over the first year as the base settles and organic matter breaks down. Top up in the second spring rather than overfilling at the start.
Drainage and the ground beneath
Where the bed sits on soil, leave it open to the ground. Roots can go deeper than the bed itself, worms move in and out, and water drains away naturally. Loosen the soil at the base before you fill.
Where the bed sits on a patio, a path or another hard surface, it needs somewhere for water to go, or the bottom of the soil stays saturated and roots drown. A layer of coarse material at the base helps, and raising the bed very slightly on the hard surface lets water escape at the bottom rather than sitting in it.
Shapes, runs and adding on later
Because the system is modular, the bed does not have to be a rectangle. Turn corners, step it down a slope, run an L along two boundaries, or build a series of narrow beds with paths between them.
It also means you are not committing to a final layout on day one. Beds can be extended, shortened or reconfigured later, and blocks from a bed you no longer want go into the next project rather than into a skip. That is a genuine advantage over anything built with mortar or screws.
Get it right first time
The one thing worth knowing: make the paths between beds wider than you think.
Everyone maximises growing space and regrets it. A path that is comfortable when the beds are empty is impassable in July, when everything is leaning over the edges and you are trying to get a wheelbarrow between them.
Allow enough width for a barrow with room either side, and more where you will kneel to work. Growing space you cannot reach is not growing space, and it is far easier to plan generously now than to move an established bed later.
Ask our engineer
Questions about bed heights, filling, or planning a layout? Ask below, or get in touch directly.
Common Questions
Is recycled plastic safe for growing vegetables?
Yes. The material is inert recycled polypropylene and will not leach into growing soil. Unlike some treated timbers there is nothing applied to the surface that can move into the bed, and unlike metal there is nothing to corrode.
It locks the waste plastic up rather than releasing it.
How long will a PolyBrick raised bed last?
25 years under warranty. There is nothing to rot, rust, splinter, shrink or warp, and the material is UV stabilised so it does not go brittle or bleach in sunlight.
It needs no treating, staining or lining at any point.
Do I need tools to build a raised bed?
No. Blocks push-fit together, and a tap with a rubber mallet seats them fully. There is no mortar, no screws and no cutting, so a bed goes up in minutes rather than days and needs no construction skill.
What base does a raised bed need?
Flat and firm ground. It does not need a construction-grade base, but the first course sets everything above it, so level it properly and check with a spirit level in both directions.
On a slight slope, dig into the high side rather than packing up the low side.
How deep should a raised bed be?
Low beds suit ornamental planting and salad crops. Mid height is the practical vegetable bed: enough root depth for most crops, warms early in spring, and comfortable to sit on the edge while working.
Waist height removes kneeling and bending entirely and can be worked from a wheelchair, which is the single most common thing people wish they had done.
What is the cheapest way to fill a deep bed?
Fill the bottom third with coarse woody material, upturned turf, or clean rubble where drainage matters. It breaks down slowly, feeds the bed from below and saves a great deal of bought soil.
Good topsoil and compost go above it, which is the layer plants actually use. Expect the level to drop in the first year and top up the following spring.
Can I build a raised bed on a patio?
Yes, but the water needs somewhere to go, or the bottom of the soil stays saturated and roots drown. A layer of coarse material at the base helps, and raising the bed very slightly on the hard surface lets water escape rather than sitting in it.
Where the bed sits on soil instead, leave it open to the ground.
Can I extend or move a bed later?
Yes. Because the system is modular and there is no mortar or fixings, beds can be extended, shortened or reconfigured, and blocks from a bed you no longer want go into the next project rather than into a skip.
You are not committing to a final layout on day one.
Do the beds need lining?
No. There is nothing to protect: the material does not rot or corrode and does not need separating from wet soil, which is why timber beds are often lined.
Leave the base open to the ground where you can, so roots can go deeper and worms can move in and out.
