Greenhouse Climate Calculator

Yes. For many combinations of dome size, climate, and growing goal, the dome's standard kit does the climate work on its own: pond, shade cloth, vents, fans, and undersoil ducting. Most Growing Domes operate this way for most growers most of the time. If you change your inputs to a more demanding goal, like year-round warm-season production or active summer fruiting in a hot climate, the recommendation will shift accordingly.

In the default Relaxed mode, the calculator sizes equipment to your specific site, not your zone. It uses your zip code's January and July climate normals to pick a design temperature. So a Pagosa Springs site at high elevation in the Rockies and a Fairbanks site in interior Alaska end up with very different equipment recommendations even though both are in the cold-continental zone. Strict mode ignores site-specific data and uses a zone-representative design temperature instead, so two sites in the same zone get the same recommendation. The "How we set your zone and target temperatures" disclosure shows both numbers.

Both apply, in different scenarios. The Relaxed number comes from your local climate and drives the recommendation in the default mode. The Strict number is the zone-wide design temperature and drives the recommendation only if you turn Strict mode on in advanced options. Showing both lets you see the difference between what your dome will actually face at your site and what a strict design-day spec for your zone would require.

Default Relaxed mode returns the equipment most owners actually need. It uses your site's actual climate and credits the dome's pond and passive systems. Strict mode returns the equipment required to hold your target temperature with no drift through the worst hours of the year. Turn on Strict mode if you want productive year-round warm-season fruiting like January tomatoes or peppers, are growing high-value crops where any temperature swing is unacceptable, or you're preparing specs for a contractor or commercial partner who expects design-day numbers. Most customers don't need it.

Not exactly. The calculator handles temperature and humidity, including the heat impact of solar gain. But useful winter light is a separate problem: even if the dome holds the right temperature, warm-season crops won't be productive in low winter light. A Seattle dome can stay at 50°F all winter without active heat, but whether your tomato plant sets fruit in December at Seattle's latitude is a different question. Cool-season crops like greens, brassicas, and root vegetables tolerate low light and grow fine wherever the dome holds enough heat. Productive winter fruiting of warm-season crops in the northern half of the U.S. usually needs supplemental lighting, which is a separate decision from heating.

The calculator uses long-term monthly temperature and humidity normals from NASA POWER, mapped to one of six climate zones. For most locations this produces a reasonable classification. Sites with unusual microclimates such as high altitude, exposed valley winds, coastal moderation, or urban heat may behave differently than the zone implies. Note that the Relaxed-mode design temperature comes from your specific zip's normals, so site-to-site differences within a zone are still captured for equipment sizing. For unusual sites or technical review, verify against ASHRAE design temperatures for your specific location.

The calculator assumes you've built and run your dome the way it was designed, including the standard above-ground pond. The pond is part of how the dome regulates climate: it absorbs heat during the day and releases it at night, and the calculator's sizing math explicitly credits that contribution. If you're building without the pond, the calculator will probably understate your equipment needs and the default sizing approach doesn't directly apply. Reach out to Growing Spaces for a project-specific review.