G’ day to all,

OK big changes in my original plans to build from scratch a Greenhouse. I have now decided to buy a much smaller Palram Snap & Grow 6 x 8 ft. Greenhouse and place it next to my house with good Winter sun exposure and protection from the North wind. My intended use will be mainly for growing vegetable plants from seeds that will be transplanted later to my garden. I will also try to grow some tomato and cucumber plants through the Winter in large containers.

My question is what type of floor should I have inside?
1) Natural earth with paver stones for a center walk path.
2) Use paver stones for the entire floor set over black plastic with drain holes.
3) Treated lumber raised off the natural ground.
4) Pea Gravel to cover the entire floor about 3 to 4 inches deep on top of black plastic with holes for water drainage. Maybe some paver stones in the middle for a walk path.
5) Open to any and all other suggestions.

I am also open to any pros and cons to the above listed options denoting any real advantage or a serious disadvantage.

Thanking all in advance for your help,

Thomas,

I have no greenhouse so take this with a grain of salt. In the future we will be building a hoop house or a greenhouse and I was also thinking about this.
I was thinking along the lines of #4 but instead of black plastic, I would use a white so it would reflect the heat. (not sure I want to be walking in a green(hot)house with a black flooring.

Is there a reason you would go with the Palram instead of a HF 6x8 at half the cost? Just the cheap construction?

-Stewart

In my little 6 x 10 lean-to GH, I have pea gravel over weed barrier over sand and then pavers down the middle. Works for me as it drains well and doesn't stay wet. Wood might get slippery if it gets wet. Dirt floor - I'd have a lot of plants growing from fallen seed. Maybe not a bad thing.

My Harbor Freight greenhouse is build on top of treated-wood decking. It is sturdy and not slippery. However it was cold and leaky in the winter. I covered it with rubber mats, the kind you put together like a puzzle, also from Harbor Freight. We had a mild winter last year but it stayed warm inside with the floor covered, bubble wrap on the walls, and mylar across the back to reflect the sun. I find that firm flooring makes it easier for me to drag large heavy pots across the floor.

Hi @PlantMania

The black plastic would be under the Pea Gravel and is used to prevent grass and weeds from growing inside. It also serves to help prevent the gravel from being pushed into the ground. I will be using the material that is used for a liner for water / fish ponds. It is thick and should out last me.

I looked at a HF greenhouse and the construction is not what I want. I am being very kind and trying not say anything offensive.

The Palram is strong, well braced and has better overall quality.

Thank you Stewart,

Hi @Shadegardener

Cindy, that is very good news in as much you are using this particular method and it works good for you. I do not want a lot of moisture and was hoping the gravel would work as a barrier against the cold ground during the Winter.

Thanks for the first hand knowledge,

Hello @ShadyGreenThumb

I live in the zone just north of you Cheryl, and I was afraid of the cold getting under a wood floor. However I do like the idea of the rubber mats, those can be replaced if needed. You are right about the sturdy wood floor for anchoring the GH to it and the support for anything heavy. I also like the use of mylar as a heating agent. Lots to think about and why I am seeking good advise from the Forum.

Thank you Cheryl,

@Thomas75

LOL That's why I put " cheap construction" in there - I have seen your first drawings I figured this was the case (they look amazing).

My first attempt will be cheaper of the cheap as I want to make a hoop house that I can cover for our month of cold weather. When Spring hits, I want to take the cover off and let it go for the other 10 to 11 months.

If you come up with a way to keep the place cooler than 115 in the shade in Texas ya gotta let us know.

If there was a pocket of air, of some sort, between the ground and the top layer of walkway - does anyone think that would be a good insulator to keep it cooler?

PlantMania said:@Thomas75

LOL That's why I put " cheap construction" in there - I have seen your first drawings I figured this was the case (they look amazing).

My first attempt will be cheaper of the cheap as I want to make a hoop house that I can cover for our month of cold weather. When Spring hits, I want to take the cover off and let it go for the other 10 to 11 months.

If you come up with a way to keep the place cooler than 115 in the shade in Texas ya gotta let us know.

If there was a pocket of air, of some sort, between the ground and the top layer of walkway - does anyone think that would be a good insulator to keep it cooler?

I have planned on a small hoop house out in the garden for this coming Spring and do as you suggested. Get the plants in the ground early, protect them with the HH and after the middle of March remove the covering and install a trellis.

I am still working on my Spring 2017 garden plans, so most likely many changes until then.

By the way, air is a great insulator if you can figure out a way to isolate a "bubble" of air. Think how cool a cinder block building is during the summer. The 3 air cells in each block is the ticket.

Thanks again,

I like cheap. Spent about $100? IDK I didn't add it up but it wasn't much to reinforce the walls using the Harbor Freight Greenhouse Blog, the Experts at then ATP who have build one before, and the instructions. Well, I was just joking about the instructions part. They sucked. But I got it done. And it is sturdy as all getout. I like that it sits on the deck, something stable in case we get those hurricane force winds. I also insulated the base and secured it doubly using cedar fencing. It's not totally insulated but I can keep it at 65º using one radiating dish heater if I want.

If you read the blog you will get all kinds of good ideas in there for the HFGH and others, I think. If you read the Post you will get even more better ideas from the good folks here. It's a long thread full of fun stuff. We didn't go off track too much. But you will see in my first post, I was considereing the Palram and ended up with HFGH. All I know is that you should get the biggest you can afford that you can fit into your space. There just never is enough room in them for all we want to do!
The thread "Harbor Freight Greenhouse projects" in Greenhouses forum

Oh and I got the mylar sheet last year from the packing of a large screen TV. DH was so excited about the TV. I got excited about the wrapper it came in. It has foam backing adding more insulation to my bubble-wrapped walls. I cut it at the seams and it was more than 12 feet long! I installed it to the frame using binder clips. The sun bounced off it in the winter. Both the TV and the mylar are still working just fine! So go chase down a Geek Squad truck and maybe they will give you some TV packing?

ShadyGreenThumb said:I like cheap. Spent about $100? IDK I didn't add it up but it wasn't much to reinforce the walls using the Harbor Freight Greenhouse Blog, the Experts at then ATP who have build one before, and the instructions. Well, I was just joking about the instructions part. They sucked. But I got it done. And it is sturdy as all getout. I like that it sits on the deck, something stable in case we get those hurricane force winds. I also insulated the base and secured it doubly using cedar fencing. It's not totally insulated but I can keep it at 65º using one radiating dish heater if I want.

If you read the blog you will get all kinds of good ideas in there for the HFGH and others, I think. If you read the Post you will get even more better ideas from the good folks here. It's a long thread full of fun stuff. We didn't go off track too much. But you will see in my first post, I was considereing the Palram and ended up with HFGH. All I know is that you should get the biggest you can afford that you can fit into your space. There just never is enough room in them for all we want to do!
The thread "Harbor Freight Greenhouse projects" in Greenhouses forum

Hey again Cheryl,

Thank you for the link. I have read a lot about the HF GH and about as many other brands as I could find. I know that making it as big as possible is good advice from everybody that owns a GH. Where I have decided to place the GH restricts the size in my case, it will be next to my house and an A/C unit on one end and a driveway on the other . My other location where I had planned to build would require me to tear down and move one of my sheds and cut down a couple of large trees, which I have decided not to do this year. I just purchased a new tractor and implements so now I am concentrating on preparing the ground for a bigger garden for next year I might get even crazier and till up a huge area around the garden and plat all of that in mixed flowers and milo

Again thanks

My new Greenhouse is supposed to be delivered this coming week but I will not be able to assemble it maybe until next week. I have tomato plants in the spot where the GH is to be placed. I might go ahead and try to transplant the tomatoes to another spot, but with all the heat and lack of rain, not sure if the plants will survive a move????

I will make my "foundation" out of treated 2 x 8 lumber and use two (2) layers and stagger joints on all of the ends/corners. This will give me a good overlap for added strength and will secure the lumber to each other with monel deck screws. Then I will secure the GH to the foundation with the monel screws.

When I build the awning cover over the GH the aluminum framework will be tied into the GH with special built aluminum brackets and to the foundation lumber also. With this added bracing I would think that the polycarbonet panels would be blown out before the framework will fail.

I still have not decided how to finish the floor area, still open for help and suggestions.

Thanks

Thomas, I see @DrDawg hasn't chimed in here yet -- he may have some good suggestions for the GH floor.

Weedwhacker said:Thomas, I see @DrDawg hasn't chimed in here yet -- he may have some good suggestions for the GH floor.

Hi Sandy,

Actually Ken has been a lot of help, I had communicated directly with him about my original plans. He has a wealth of knowledge and experience with greenhouses, maybe he can think of something else to suggest about this new plan of mine.

The GH is supposed to be delivered sometime tomorrow. Now I have to decide whether to try and relocate some veggies and set up the GH or wait until they are done.

Hey, everyone. There has been some good comments so I just stayed out of it since my greenhouses are used differently. Also, I have posted the construction of my flooring several times over the last few years and did not want to repeat that. But since y'all asked and just to refresh, my subflooring is simply cypress mulch, but it is the "clean", premium grade, sold in bags at Lowe's. That subflooring will be 3-4" thick, but in the walk area between the benches, it will be up to 6" thick. Over that subfloor is fabric greenhouse flooring sold by several greenhouse supply companies. I used black fabric to help with heating in the fall and winter. One fabric-floor is now five years old and the other is 3.5 years old and both have held up well. I went with this type of sub-floor/floor for two reasons. I wanted the floor to drain well yet hold moisture, so that humidity would be increased, and I wanted something soft to stand on. I am not using any stone, gravel, or pavers whatsoever. I refresh that cypress mulch every other year.

Hi Ken, is your greenhouse elevated or on a slope and is your drainage OK? I will have a slight slope for about 15 feet and then a really good slope out to the road. One of my small gardens is currently in this location and so far never had any problems with standing water.

Wish I could pour a cement floor for the new GH but cannot where it will be next to the house. Right now I am leaning toward the Pea Gravel floor but still undecided.

Thanks for all the help

My greenhouses were at about the same elevation as the surrounding yard (the 4x4" foundation is about 2" above grade), but having the flooring built up 4-6", there is never water standing. The periphery of my greenhouses is also mulched and there are evergreen shrubs between the walls of the two greenhouses and the paver walkway that goes between the greenhouses.Again, you are not growing plants that I do, so your flooring needs are nothing like mine. That's why I never chimed in..........just didn't think my layout would be as practical for you, Thomas.

These photos are 2.5 yrs. old. Its in the dead of winter, thus the solar material covers. The landscape plants (Euonymus 'Manhattan') are now 3' tall and I keep them trimmed to that height. By the way, the 'Manhattan' is as close to a near-perfect landscape plant as I have ever grown.

drdawg said:My greenhouses were at about the same elevation as the surrounding yard (the 4x4" foundation is about 2" above grade), but having the flooring built up 4-6", there is never water standing. The periphery of my greenhouses is also mulched and there are evergreen shrubs between the walls of the two greenhouses and the paver walkway that goes between the greenhouses.Again, you are not growing plants that I do, so your flooring needs are nothing like mine. That's why I never chimed in..........just didn't think my layout would be as practical for you, Thomas.

These photos are 2.5 yrs. old. Its in the dead of winter, thus the solar material covers. The landscape plants (Euonymus 'Manhattan') are now 3' tall and I keep them trimmed to that height. By the way, the 'Manhattan' is as close to a near-perfect landscape plant as I have ever grown.

Ken your floor looks comfortable enough to sleep on

Really like the mulch on the outsides and the Manhattans look great and would imagine help in the temperature control. Might just copy some of your ideas.

Thanks again,

I was so impressed with the Manhattan, that I decided to propagate them. It is the only (true) landscape plant I propagate. They handle practically any growing conditions thrown at them and I like that.