The Problem

Installing a greenhouse directly onto grass might seem like the quickest option, but it almost always leads to issues. Grass surfaces are naturally uneven, soft underfoot, and constantly shifting with changes in weather. What looks level today can quickly become patchy, sunken, or uneven after just a few weeks of use.

The biggest concern, however, is drainage. Grass and soil alone do not provide a reliable draining surface. When it rains, water sits in the ground, creating soft, muddy conditions. Over time, this leads to movement beneath the greenhouse, making the structure unstable.
Because a greenhouse creates heat and humidity internally, poor drainage externally only makes things worse. Excess moisture builds up around the base, turning the area into a damp, messy environment

The Outcome

Without a proper base, the problems quickly escalate beyond appearance.

• The greenhouse begins to sink or shift, causing it to fall out of level
• Doors and vents stop opening properly due to frame movement
• Water collects underneath, leading to poor drainage and constant dampness
• The surrounding area becomes muddy, untidy, and unusable
• Internal growing conditions become harder to control due to excess moisture

Instead of creating a clean, controlled growing space, the greenhouse becomes difficult to use and maintain — and over time, this can even impact the longevity of the structure itself.

The Solution

The solution is to install a Gorilla Eco Base — a purpose-built system designed to create a firm, level, and free-draining foundation for your greenhouse. This system uses a durable plastic grid (matting) installed over a properly prepared sub-base to ensure both stability and drainage.

How it’s installed:

• A 100mm layer of compacted hardcore (MOT Type 1) is laid to form a solid foundation
• This is blinded with 25mm of crushed limestone to create a smooth, stable surface
• The Eco Base grid is laid and levelled, with sand used if needed for fine adjustments
• Once the greenhouse is installed, the grid is filled with pea gravel

It’s completely normal — and recommended — for the base to extend slightly beyond the greenhouse footprint. This allows the area around the structure to also be filled with pea gravel, creating a clean, practical border.

The Result:

• A strong, level base that won’t move or sink
• Excellent drainage, preventing water build-up and mud
• A clean, low-maintenance finish all year round
• Improved airflow and moisture control around the greenhouse
• A tidy, usable space both inside and around the structure

By installing a Gorilla Eco Base, you’re not just putting a greenhouse in your garden — you’re creating a stable, well-drained environment that allows it to perform exactly as it should.