Most greenhouse regret is decided before the order is placed, in the questions the buyer never asked themselves. 🧭 Not questions about brands or panel thickness, but about their own yard, their own habits and their own winter.
Here are the twelve we would put to anyone thinking about it, in the order that matters. Answer them honestly on paper, and by the end you will know not only whether to buy, but what to buy. Some of them are uncomfortable. That is deliberate. ✍️
1️⃣ 🎯 What do I actually want to do in it?
"Garden more" is not an answer. These are answers: start seedlings six weeks earlier, grow tomatoes that ripen properly, overwinter a lemon tree, have somewhere to sit surrounded by plants in April. 🌱
Write down the specific thing. Everything else in this list depends on it, and the people who skip this question are the ones who end up with a structure that technically works and never quite gets used. 📋
Why it matters so much
A production greenhouse and a garden room are different buildings with different materials, different foundations and different budgets. Deciding which one you are buying is genuinely the whole game. 🏗️
2️⃣ ☀️ Where does the sun actually fall in my yard?
Not where you think it falls. Go outside three times in one day and note the shadows. ⏰ You are looking for a spot with at least six hours of direct sun in the growing season, and ideally decent winter sun, which is a separate question because the sun sits far lower from November to February.
The most common trap is the spot that looks perfect in June and sits in the shadow of the house or a neighbor's conifers all winter. 🌲 If your main goal is season extension, winter light is the light that counts.
3️⃣ 📐 Is the ground level, and where does the water go?
Take a string line and a four foot level out today, before you shortlist anything. Two numbers matter: how much fall there is across the footprint, and where water sits after heavy rain. 💧
- ✅ Under two inches of fall: straightforward, gravel base handles it
- ⚠️ Two to six inches: a leveled and edged base, more work but routine
- 🚩 Over six inches: excavation or a low retaining edge, plan the time and cost
And if the spot holds a puddle for a day after rain, it will hold it under your greenhouse. Either fix the drainage or move the greenhouse. 🌧️
4️⃣ 📏 How much space will I genuinely fill?
Be pessimistic about your restraint here. A greenhouse fills faster than any other yard structure, because every seed tray, every pot and every overwintering plant is a claim on bench space. 🧺
The near-universal regret is buying too small. Nobody tells us their greenhouse turned out bigger than they needed. And because cost per square foot falls as a structure gets longer, the extra length is the cheapest floor area in the whole purchase. 📉
5️⃣ 💰 What is my real budget, including the base?
The structure is sixty to eighty percent of what you will spend. The rest is base materials, tools you may not own, interior flooring and the first season of pots and benching. 🧾
A workable rule: take the structure price, add $250 to $400 for a gravel base, add $300 for tools and fasteners if your shed is bare, and add $150 to $400 for the first season. We broke every line down in our full cost guide. 📊
⚠️ The trap to avoid: letting the base and tools line push you down a tier on the structure. Those costs happen once. The structure is what you live with for two decades.
6️⃣ 🧊 Am I buying a growing tool or a room?
This is question one asked again, sharper, because it is the one that decides material.
- 🏗️ A growing tool points to twin-wall polycarbonate: better insulation than single glazing, effectively hail-proof, the most floor area per dollar. The Timeless is the model most growers grow into rather than out of.
- 🏛️ A room points to glass, because you want to see out and you want the building to look like architecture rather than equipment.
- 🪵 A room with warmth and character points specifically to wood framed glass, which reads traditional where aluminum reads contemporary.
None of these is the upgrade and the others the compromise. We laid the trade-offs out with the actual numbers in our polycarbonate versus glass comparison. 🔍
7️⃣ ❄️ What does my winter actually do?
Three specifics, and you probably know all three already:
- 🌨️ How much snow, and does it sit? Snow load ratings matter, and ours are published, 3 ft on the polycarbonate range.
- 💨 How exposed is the site to wind? Published ratings again: 65 mph on our polycarbonate models, 115 mph on the aluminum glass ones.
- 🥎 Do you get hail? If yes, this weighs heavily toward polycarbonate.
These are not abstractions. A greenhouse is the only thing in your yard that has to survive every storm with glazing intact. 🌬️
8️⃣ 🔥 Will I heat it, or accept an unheated season?
Most owners do not heat, and that is a perfectly good outcome. An unheated greenhouse still gives you frost protection, several extra weeks at each end of the season, and a place for winter salad greens and hardy greens. 🥬
If you do intend to heat, know the number before you buy. Holding a 100 square foot greenhouse just above freezing through a cold winter runs roughly $40 to $120 a month. Keeping it at tomato temperatures in January runs several times that, and for almost every home grower exceeds the value of the harvest. ⚡
💡 Cheap middle ground: thermal mass in the form of black water barrels, bubble insulation on the north face, and a frost cloth tunnel inside for the coldest nights. Together they typically buy five to ten degrees for a one-time cost under $150.
9️⃣ 📜 What do my local rules say?
Ask this before you order, not after. The rules are local and the internet's confident answers are frequently wrong for your address. ⚠️
The code baseline most US jurisdictions adapt generally exempts detached accessory structures up to 200 square feet from a building permit. But many places set a lower threshold, often 120 sq ft. Some require a zoning permit at any size. And regardless of permits, setbacks, lot coverage limits and easements still apply, as do HOA covenants, which are a separate authority with their own rules on height, materials and placement. 🏘️
📞 One call to your local building department, describing footprint, height and anchoring, settles it in five minutes. Note that the larger models on the market exceed the common thresholds, so this call matters more the bigger you go. Adding electricity or plumbing almost always triggers a permit of its own, whatever the size.
🔟 🚚 Can a pallet actually reach my yard?
Greenhouses ship as freight, on a pallet, delivered curbside by a liftgate truck. That means the pallet lands at the end of your driveway and the rest is up to you. 🚛
Walk the route now. Measure the gate. Count the steps. Look at the corner between the narrow side yard and the backyard. Three people and a hand truck handles most deliveries comfortably, but it is a thing to arrange rather than improvise on the day. 💪
1️⃣1️⃣ 🔨 Do I have the time and the second pair of hands?
Assembly is not difficult, but it is real work: plan on two to three days with two people, on a base that is already finished and level. No professional installer is needed. 🧰
Two honest sub-questions. Do you have a free weekend in the delivery window? And is there someone who will hold the other end of a panel without complaining by hour six? If both answers are no, factor in the cost of hiring help rather than assuming it will work itself out. ⏳
1️⃣2️⃣ 🤔 Am I buying this for the gardening, or for the idea of gardening?
The hardest question, and worth sitting with. 🪴
A greenhouse rewards regular attention. Not much of it, but regularly: opening vents on a warm morning, watering, noticing when something is struggling. If your existing garden is neglected because you are never home, a greenhouse will not fix that. It will just be a more expensive place for the same plants to be neglected. 😅
Conversely, if you already garden and the limit on what you grow is the weather rather than your interest, this is exactly the purchase that removes that limit.
🚩 Three answers that mean wait
- ❌ You cannot name a specific thing you want to grow or do inside. Wait a season, garden harder, see what the constraint actually is.
- ❌ The only viable spot is in shade for half the year. Solve the site problem first, or the greenhouse will underdeliver forever.
- ❌ The budget only stretches to a disposable kit. A season in raised beds teaches you more, and costs less, than a structure that fails in the first windstorm.
None of those is a permanent no. They are just reasons the answer is "not this year", and we would rather say so than sell you something that disappoints you. 🤝
❓ FAQ: questions to ask before buying a greenhouse
What is the most important question of the twelve?
The first one. What do you specifically want to do inside? Material, size, foundation and budget all follow from it, and buyers who skip it are the ones who end up with a structure that works on paper and goes unused. 🎯
How do I know what size to get?
Mark the footprint in your yard with stakes and string, leave it for a few days and walk past it. Then look seriously at the next size up, since cost per square foot drops with length and buying too small is the most common regret in greenhouse ownership. 📏
Do I need to answer the permit question before ordering?
Yes. Thresholds vary by jurisdiction, setbacks and HOA rules apply even when no permit is required, and it is a five minute phone call. Doing it after delivery is how people end up with an expensive structure in the wrong place. 📜
Is an unheated greenhouse worth having?
Absolutely, and it is what most owners run. You get frost protection, several extra weeks at each end of the season, and winter salad greens, at essentially zero operating cost. 🥬
How long should I expect to spend building it?
Two to three days with two people, on a base prepared in advance. The base is the job to do while you wait for delivery, not the weekend before. 🔨
🌿 If you answered all twelve
You now have something more useful than a shortlist: a specification. 📝 You know the use, the site constraints, the size range, the material family, whether you will heat, and what the delivery and build actually demand of you.
That is the point at which browsing models becomes productive rather than confusing, because you are filtering against your own answers instead of comparing photographs. 🧭 The Prime Greenhouses range publishes footprints, ridge heights, wind and snow ratings on every model, so you can check your specification against real numbers rather than marketing copy.