Before you decide, check five things on site: sun exposure, soil and drainage, climate, ground level, and your anchoring materials. Whatever base you choose, it must be level, square and securely anchored before the frame goes up.
Use a raised or stepped perimeter base rather than regrading the whole site.
Level the base, not the entire yard — adjust height with timber, block, stone or gravel.
Compact the sub-base thoroughly and add landscape fabric under gravel.
Square the base by measuring both diagonals before any frame goes up.
Anchor securely, and size the base for the longest house you might extend to.
No — a base is optional on every Planta greenhouse. The galvanized legs extend about a foot into the ground and will hold the structure on their own. A base is what protects it from freeze–thaw movement, improves wind and snow-load performance, and stops long-term settling.
A timber perimeter filled with compacted gravel. It is the best all-round DIY base: adjustable in height so it forgives uneven ground, quick to build, and it drains well.
Concrete. It gives the best wind resistance and the least movement over decades. You can pour a full slab or just a perimeter footing — the footing is cheaper and still lets you plant in the ground inside.
Gravel. Water passes straight through, so there is no standing moisture and no mud. Lay landscape fabric under the gravel and compact the sub-base thoroughly.
Yes. Use a raised or stepped perimeter base and level the base rather than regrading the whole yard — adjust the height with timber, block, stone or gravel.
Level and square before any frame goes up — measure both diagonals and adjust until they match. Building on an out-of-square base makes the frame and panels difficult to fit.
Yes, with a wooden, gravel or perimeter-footing base — all three leave the soil inside open. A full concrete slab does not, so choose a perimeter footing if in-ground beds matter to you.
Yes. Extensions come in 6.5 ft sections, and redoing the base work later costs far more than building it longer once. Size the base for the longest house you might extend to.
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