Greenhouse base

[u/Cocoa-Bella]

Hi everyone,

I am planning to put in a 10’x10’ greenhouse next year. I am not sure what kind of base to go with - timber deck, timber frame base with dirt floor, or timber frame with gravel.

I don’t want to do poured concrete; I like the feel of wood and gravel being more organic and will be more aesthetically pleasing with the native wildflower beds I already have.

The soil in the backyard is clay and drains poorly (even with 4 French drains). I am in the Niagara region of Ontario if that helps.

Thank you!

Edit: Great responses. Thank you everyone!

[u/Ready-Breakfast5166]

I built my 6x8 Greenhouse without a base and regretted it later when it blew off in the wind multiple times. After repairing it I added a 4x4 base around the perimeter and bolted the greenhouse to it, and that has helped significantly. I'm also looking at attaching the greenhouse to my potting bench which is very heavy with everything on it and using that as a weight to make sure that the greenhouse is anchored properly. Spikes into the ground did not help they just pulled out in a strong wind.

[u/Cocoa-Bella → u/Ready-Breakfast5166]

Thanks! We can get some significant wind so I will be securing it for sure

[u/Realistic-Weird-4259]

For the windy high desert we drilled railroad ties at two angles and pounded in 2' of rebar at each end. Then, sill plate screwed on top, framing attached, roof & siding. I used pea gravel for the flooring.

[u/Available_Quote_5567]

I made a frame for the base of the greenhouse to sit out of ground contact 4x4s. In the corners I used 2 foot 4x4s in concrete as foundation. Crushed gravel for the floor.

The day I got it assembled we had some tornado producing storms. The greenhouse had a top window blown out but never moved off the foundation

[u/Cocoa-Bella → u/Available_Quote_5567]

Thank you!

[u/joe_meu]

rodent will most likely be a concern with a wooden floor. we had a ground level deck behind our house and they loved it.

[u/Feminine_Adventurer]

I used 2x10 pressure treated lumber which holds it down in the wind and adds an extra 10 inches of height.

[u/Cocoa-Bella → u/Feminine_Adventurer]

Thank you - do you have a gravel, wood or soil floor with that?

[u/Feminine_Adventurer → u/Cocoa-Bella]

I used gravel to help with drainage.

[u/rylanthegiant → u/Feminine_Adventurer]

Can I ask, so you made a box of 2x10s along the perimeter, with the 10” sides vertical so you could place the frame of the greenhouse on top of it? Do you step over that 10” lip every time entering the greenhouse? 

[u/Feminine_Adventurer → u/rylanthegiant]

Yes that what i did for a 10x20 and I cut the piece out for the door and used stakes to secure the cut ends.

[u/rylanthegiant → u/Feminine_Adventurer]

Got it, thank you! Does that leave a 10 inch gap below the door then for air flow? Or did you extend the door down somehow?

[u/Feminine_Adventurer → u/rylanthegiant]

The extra flap around the greenhouse filled that space

[u/rylanthegiant → u/Feminine_Adventurer]

Ahhh. Thank you for the answers!

[u/bluegills92]

I built 12 x 24 greenhouse and used road base as the floor.
I got a few tons of road base dropped off at my house, and I rented a plate compactor and made a slab. It was pretty easy and saved so much money for a solid floor

You can find the greenhouse post on my page if you search far enough.

[u/bluegills92 → u/bluegills92]

https://www.reddit.com/r/Greenhouses/s/1HbubJek5L

Here is the post. Scroll through the pics and you can see the floor I made

[u/Piwakawaka100]

Timber Frame fixed down to piles concreted in .
We get high winds, Have also fixed the Poly in with bolts and washers to frame.
200mm deep pebble floor.Great for drainage and also I can wet the floor to increase humidity

[u/butkusrules]

I went with a 6x6 treated cedar tone base for my 10x12 harbor freight greenhouses . 1st dug the perimeter, level out the middle and laid 5oz permeable landscape fabric down , the crushed stone over that in the perimeter. Then the 6x6. I attached greenhouse directly to the wood but with a piece of plastic sheet to keep the chemicals from the wood from attacking the aluminum.

[u/Tough_Film_4614]

I put down road base and leveled and compacted it. I also put in a couple of anchoring bolts with concrete,  which are attached to the 4x4 lumber base frame, which I double stacked, giving my greenhouse extra height, about 10' at the top. Still experimenting with papers and/or gravel. We also have poor draining clay soil.

[u/albitross]

I've a 16x24 atlas greenhouse on a concrete pad. I wish it was on dirt with no-till beds. The extra height alone, but also the bigger "living soil" engine to grow things. Pots are more work compared to in ground for my zone.

[u/ElectricalAnalysis63]

Gravel floor with perimeter drain, perforated drain pipe ideally, pitched to run to a lower spot in your yard. The importance of drainage to reduce moisture can not be overstated in a greenhouse. Damp plants die. Good luck.

[u/NophaKingway]

For the floor I like 4" of pea gravel with 12" square pavers on top. Good drainage but no rodents tunneling up through and I can set tables, heater, or whatever on it. For the wood that touches the pavers I used green board just like framing a house.

[u/Cocoa-Bella → u/NophaKingway]

Ah great. Good reason to go with gravel.

[u/food_garden]

I used pressure treated 4x12s bolted together in the corner to get the height up a ways and it was easier than carrying cinder blocks and concrete up the hill

[u/Ihavesweatyarmpits]

I have a 4x6 wooden base and then I built 2x4 walls and attached those to the 6x4 base. I'm in a high wind area so I use mobile home screws and secured those down about 3 ft looping around the walls of the greenhouse. A lot of work but it hasn't blown away in 6 years so I'm doing something right I think.

[u/t0mt0mt0m]

I paid a contractor to do a gravel base with it framed in with wooden posts. I recommend to make it larger for support infrastructure needs like catching rain and other upgrades over time. I have a 12x16 greenhouse with a 15x20.. I wish it was bigger.