The Canadian Greenhouse Planner
Stop guessing what your greenhouse will cost to run.
A complete planning system for cold-climate Canadian greenhouses. Enter your postal code and get your design temperature, your degree-days, your frost depth, your winter sun angles — and a calculator that turns them into a heater size, a fuel bill, a bill of materials and an honest payback figure.
Get the planner — $29Instant download · Guide, workbook, calculator and six field cards · Free updates for 12 months
The number that decides where your greenhouse goes. Every location in Canada has a midwinter shadow multiplier set by its latitude. Multiply the height of anything to your south by it, and you have the length of shade it throws at noon on the shortest day. Near Ottawa a three-metre hedge reaches almost eight metres — straight across the spot most people were planning to build. The planner gives you yours, and siting stops being an opinion and becomes a tape-measure job.
Most greenhouse advice is written for zone 7
It tells you to ventilate, to face south, to consider polycarbonate. All true, all free, and none of it tells you what size heater to buy for a February night in Saskatoon.
This planner does. You enter your postal code once. It resolves to one of 64 Canadian reference locations and fills in every number the rest of the process needs — then a spreadsheet turns those numbers into decisions you can act on.
It is deliberately opinionated. Where there is a defensible right answer for your climate, budget and goal, it gives it rather than listing options.
What you get
The Guide
Every decision in build order, from siting through to what goes wrong. Not greenhouse theory — the part that comes after.
The Workbook
Fillable worksheets you can print as often as you like. You will get the first two wrong, and that is the point of doing it on paper rather than in lumber.
The Calculator
Opens in Excel, Google Sheets, LibreOffice or Numbers. No account, no subscription. Enter your postal code; every downstream number follows.
Field Cards
One page each, made to be printed, laminated and taken outside. Site walk, snow load, cut list, build day, spring ventilation, winter maintenance.
What makes it different from a good blog post
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Your numbers, not generic ones
Design temperature, heating degree-days, frost depth, frost dates and winter sun angles — for your postal code, not for somewhere vaguely similar.
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Arithmetic a blog post structurally cannot do
Heat loss, seasonal energy, nine fuels priced on delivered heat, a bill of materials that re-quantifies when you change the size, and a payback figure.
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Decisions, not options
Free content lists glazing types. This one says: given zone 3, a frost-protection target and this budget — use twin-wall polycarbonate at 8 mm, and here is why.
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The snow load done properly
Published values vary enormously over short distances — in British Columbia, 1.1 kPa at Victoria and 9.5 kPa at Whistler. So the structural check stays locked until you enter a value you have confirmed with your municipality, and the planner shows you how to get it in a ten-minute phone call.
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A failure catalogue
Ten ways these projects fail, with cause, cost and prevention. Avoiding one of them returns the price many times over.
The honest part
The worked example that ships inside the calculator is a 3.6 × 6.0 m twin-wall greenhouse near Ottawa, held just above freezing.
It does not pay back inside ten years. It is still negative at ten.
We ship that example on purpose. Many greenhouses never pay back financially and are still obviously worth building. You should decide with the real number in front of you, not a hopeful one.
Who it is for
- A competent DIYer — comfortable with framing, hand and power tools, and reading a plan.
- Anyone engaging trades for electrical, gas and, where triggered, structural work.
- Anyone who would rather hand a contractor a specification than a vague idea.
Who it is not for
- Anyone wanting engineered drawings. This is a planning tool — it tells you where the edge is and when to hire a professional. It does not size structural members.
- Anyone outside Canada. The climate data, snow loads and codes are Canadian.
- Anyone who only wants to start tomatoes a few weeks early. A cold frame and row cover will do that for under $200 — and Section 2 says so.
CAD · Introductory
This is a first edition with no testimonials behind it yet. The scope carries $49–79 once it has them, and the price will rise. Buying now costs you less and costs us the difference — a fair trade for going first.
Get the planner — $29Instant download · Free updates for 12 months
Questions
Do I need Excel?
No. The calculator opens in Excel, Google Sheets, LibreOffice and Apple Numbers. No account or subscription needed.
Will this work outside Canada?
Not properly. Climate data, snow loads and code references are Canadian. The method ports; the numbers do not.
Does it cover attached or lean-to greenhouses?
The planning process applies, but an attached greenhouse is an addition to your house with different structural and permit rules. The planner tells you plainly that this is engineer territory rather than pretending otherwise.
Is this just your free greenhouse guide as a PDF?
No — and that was the design constraint the whole product was built against. The free guide explains cold-climate greenhouses. The planner decides what you should build, on your site, and what it costs you to run. Different question, different product.
Planning guidance, not engineered drawings. No structural member is sized here, and the calculator’s structural check does not produce a result until you enter a ground snow load confirmed with your local authority. Electrical and gas work must be done by licensed trades. Permit requirements vary by municipality — confirm before building. Full terms and scope.
