I have the space in my little urban plot of 0.15 acres to put a greenhouse. It will be 5m long and 3m wide, facing due south and I’m in the UK, hardiness 8-ish, very damp.
I want it to
•extend the season- so I can put seedlings outside earlier before they take over the house (my home has no south facing windows at all, and the east and west facing ones are heavily shaded).
•overwinter things and grow things I can’t grow outdoors here (Meyer lemon plant, overwinter hot chillis and maybe tomatoes).
•grow salad greens in winter (that’s probably the easiest one to manage!).
•to put my more sensitive fruit trees/plants in there- dwarf peach, nectarine and apricot, passionflower, to give them a longer and hotter season and get more fruit.
Building and materials aren’t an issue- family of builders so I can acquire most things from demolitions eventually. A ‘regular’ greenhouse for this space would be £1300- I’d like to spend about a quarter of that! But assume I can get most materials for free if I wait long enough.
Now, bearing all my conflicting ‘wants’, what are my best options? I want too many things and can’t reconcile that I want to keep plants with a chill requirement, yet overwinter chillis that require a 3-5 degree C minimum!
A bit about my site: its dead flat, faces south. Absolutely no more space available than the 5*3m. Soil is about 30cm of topsoil over clay. Can’t get any machinery there so it all has to be doable by hand.
I was thinking a climate battery might be good for extending the season and for dehumidification (very very damp climate!)
Any other ideas/experience? Anything really obvious that I have missed?
I'm also in zone 8, but the southern U.S. has much warmer summers than where you are, so I put my greenhouse up in November and take it down in April. If I didn't, I would have an oven on the south side of the house for half a year.
My greenhouse is made from 2"x3" framing lumber, to which I attach 4 or 6 mil polyethylene sheeting. The 4 mil is good for two years, and the 6 mil I can sometimes get 3 years worth of use from. I use a new roll in the fall for the exterior sheathing, and recycle last year's bits for the interior sheathing. To keep the wind from tearing the poly off the frames, I make liberal use of wooden battens on the vertical surfaces and I nail down pieces of chain link fence on the top. The greenhouse is 6'x22' and where it is attached to the house it is 8' tall and slopes down to 6' tall at the front to let the rain run off.
I have a lemon tree, an orange tree and a kumquat tree planted along the wall of the house, and the greenhouse has kept them alive, even though we have had some nights down to -10C. I tried to stick to passive heating by having lots of buckets of water in the greenhouse, but that doesn't work when the temperatures dip below -5C. If the forecast low is less than that, I turn on a 1500 watt portable space heater and let it run all night. We only get a handful of nights with temperatures that low. What helps me is that we have warm days and sunshine, even in the winter, and the soil temperature only briefly drops below 10C, even in January. When the dirt is 10C, it provides a lot of heat for plants when there is a cover to keep that heat from radiating off into space.
Besides the three fruit trees, I have lots and lots of pots that I overwinter. I've never been able to overwinter basil, it's just too cold sensitive. But eggplants, tomatoes, peppers, avocados, a pineapple, a mango tree, lemongrass, aloes, those have all made it through. I can also start plants in the greenhouse and move them outside, although in a mild winter here greens do fine without any protection.
charli, what style of garden do you have? Sounds like it would be pretty protected as far as wind goes, so maybe you want a structure that is the same style as your house or garden? Since the two will be very closely associated, it would be nice if they complemented each other. Is it a traditional English cottage garden? Would you like a Gothic style roof on it? Is your garden modern? Would a simple frame with mostly glass or polycarbonate panels look sleek? Is your garden most vegetables and flowers? Do you want a greenhouse that looks like a sort of chicken coop/salt box style with one side of the roofline higher than the other?
You're going to be looking at it more than you will be in it, especially in the winter.
All of them would work about the same as far as keeping the temps down, and at first you could cover the frame with plastic until you got the money together to do polycarbonate panels or glass. But it should be in the shape of a structure that you love to look at every time you see it at a distance or walk through the door. Do you prefer the look of wood? Or white PVC pipe? Or silver alumiinum framing? Don't just go for cheap. Go for your own style.
Something with an arbor attached to it.
This is a nice link that talks about different styles:
That's what thing I hadn't thought about at all- what it should look like! Told you I'd have missed something obvious!
So my garden is surrounded by trees, so pretty protected. I don't have to build foundations for frost heave or to withstand any significant snow load- as we don't really get either here. And I'm not sure how to describe my garden.. I suppose I'd like it be an 'English cottage garden'- its got Victorian houses in the background- but my greenhouse budget doesn't stretch to a Victorian orangery! Its just wooden beds of fruit and veg, and a chicken-run. I'm not big on 'style', as you can tell.
Now... my 'garden' can't actually be seen from my house (its a very odd setup, my 'garden' is a bit of land I own that's near my house- its not attached, and my house doesn't have any kind of garden). So on one hand I won't have to look at it from the house or windows or anything. But on the other hand I'm going to give this more thought, as I would like it to be pretty!
charli, then you've got a blank slate and you can choose whatever you've dreamed up. You mentioned a Victorian orangery, so is that appealing? White frames, traditional style? Or more a more rounded roofline? An Octagonal end?
I've found that everything else about what I do needs to be practical, and frankly, boring. So to be more artistic, more creative with a greenhouse makes it the perfect place to do a style, use decorative doors and frames in ways you couldn't do in the practical world.
You can make greenhouses with iron rebar and PVC pipe slid over it (sorry, I don't know what you guys call it) but the white plastic plumbing pipe.) Not the smallest, floppiest size, but one or two sizes up, depending on the flexibility and the sturdiness you want. It is like tinker toys, you can bend them and connect them in almost any shape.
You can do the Gothic pointed roof with iron rebar posts with longer PVC slid down over it, and joined at the roof height with a 90 degree angle piece. That makes the wall top edges rounded, and top peak look Gothic.
You can use thicker PVC pipe to do a traditional house style (like the one you already have in the picture). You can paint PVC pipe using outdoor paint, sand it and wipe it down first. Find some old recycled windows with interesting frames and embed them in the ends on either side of the doorway.
If that is your small greenhouse in the picture, you might want to add the new one to it, make it accessible for convenience, and do something elaborate, then add a door to the small greenhouse that matches the style of the new one. Don't lose space between them that cold wind or cold air can settling between in the winter.
A low wall of stone or bricks around the base helps block out wind, keeps it warmer near the ground inside. But if you cover it with plastic you need to make a tight connection so the mice or critters can't get.
And do you have a patio sitting area with a table and chairs so you can sit and admire all your hard work? a place where friends can sit and visit. The greenhouse with the arbor attached to it is an easy add-on. At the end of summer a lot of the patio furniture sets go on sale.
Let this place be where your imagination can get set loose
Don't fall for the My-Place-Is-Special, It-Won't-Happen-Here Syndrome.