There is a guy in Texas 8a doing a lot of tropical fruit in greenhouse.
Achacha is putting on new growth! Harvested my first January fig as well (strawberry verte). Battling spider mites on mango, controlled atm, but ordered some of the heavy stuff if needed (Forbid 4F). Rooted some of our high dollar Hoyas.
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Sorry if this was already mentioned up thread, but what size is this? I’m considering Cedar-Built now and looking at all the choices, you weren’t kidding about being expensive but they really do look both attractive and sturdy so it’s probably worth it.
I asked what their turnaround time is and they said they estimate orders placed today will be delivered in September, due to unprecedented pandemic demand. So I guess I’ll be looking at a fall project rather than a summer one!
The greenhouse pictured is 10 x 20. It is a solid kit, but not perfect. The problem is other (wood) kits are even more expensive then this one. Quite a project to put together, we did the gravel foundation, but if I were to do it again I would put down a concrete pad for better insulation. What size are you looking at?
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We were thinking 12 x 16 probably, but just changed our minds about the location so we may go with 12 x 18 or even 12 x 20.
We’re only in 8b so not too worried about maximizing insulation, but the day length and cloud cover are pretty ridiculously bad in the heart of winter so maybe I am underestimating that need. Was planning to put in some intense supplemental lighting, though.
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If you are growing tropical plants heating will be a major cost. I run 2 heaters both 2800 watts to keep the greenhouse comfortably above 60 degrees (usually 65). On mild nights only 1 heater is enough, but much below 40 and you need both. Heating bill was around $250 for coldest month this year. Even in milder Seattle (I used to live there) there are many nights in the upper 30’s. The biggest heat loss is through the floor, the cracks can be sealed and even windows covered with additional plastic, but the floor is the way it is, unfortunately.
They do offer the insulated walls and triple-pane glazing as add-ons, but I’ll mostly be growing cold-hardy avocados in there (maybe some citrus) so I’m thinking they’ll be ok with just the warmth from lights. Our lows are rarely below freezing, but then again for a couple months our highs are rarely above 50, so the average is pretty low. Not really planning to grow any mangoes or truly cold-sensitive tropicals, but if the temperatures end up staying higher than expected I might try a few.
Love it! Does that cause any issues with condensation up against your exterior wall?
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Just had a thought occur to me… Have you considered putting interlocking rubber/foam flooring just right on top of the gravel? Like the kind for kids play rooms or exercise rooms:
Not sure how much additional insulation that would give you, but might be worth a shot. You’d have to get the gravel pretty level first, but seems doable.
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The condensation is limited to the glass areas because the house is warmer than the glass.
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The ground is inside the greenhouse. Once you heat the ground why would you need to reheat it. Insulate the greenhouse base perimeter with leaves and the glass area will be your biggest heat loss
I really doubt that the biggest heat loss is thru the floor. I don’t think floor loss is even included in the greenhouse heat loss calculators I’ve seen. If I’m wrong someone can point that out.
It’s often recommended to insulate the perimeter underground in cold climates. That would be a much bigger factor in a small greenhouse than a large one. After all cold doesn’t penetrate very far into soil. At 6ft the temperature is nearly constant all yr around.
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My greenhouse sits on 4 x 6 lumber on top of gravel. The issue is the gravel allows air to travel through (does not insulate). Therefore it makes sense to buffer the perimeter as you mention. My claim that the biggest loss of heat is through the floor is based upon my observations and feeling where the draft is entering the greenhouse. It is obvious when this is done that the gravel foundation is an issue. I still love my greenhouse and enjoy the way the gravel looks. If I were to do it again I would either pour a slab or add a wall footing to resolve this issue.
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Would pouring sand along the outside edge by the walls help? I’m just thinking if you block up the voids between the pieces of gravel you might cut the drafts entering through the ground. Sand would still allow some drainage if you needed it and would probably work down in more and more to fill spaces with time, rain, etc.
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OK I understand the issue better. The sand idea sounds good. Or dig out some gravel if needed and block off the draft.
The big losses on a clear night are out the sides and top as radiation to outer space.
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Today 2-2-2021 at 1:Pm with an outdoor temperature of 31F my greenhouse temperature was 86F. This greenhouse is shown in my first picture of my last post.
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In bright sunshine with little or no wind, I’ve had my greenhouse hit 120 degrees with an outside temp of 35. Solar energy is incredibly effective in some conditions.
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Phil, tractor supply sells rubber horse stall mats that a friend installed on their basement floor. A 3x4" thick 4’x6’ section is 46.99 and they are incredibly sturdy. I’m not sure if that would be a good insulation layer but you could also get creative with the foam they use on the side of houses. It’s cheaper and you could then put thinner mats on top. I’d also highly recommend a few cans of Great Stuff to seal the gaps letting air in as a first line of defense before anything else.
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