Thoughts about greenhouses
Back when wearing animal skins was chic (and necessary because we had not invented pants yet), a bunch of us were huddled around a fire chewing on burdock roots and wishing someone nearby had already invented beer. Third from the left, who was a bit mystical, said “What we need here is an enclosure which lets in light and holds in heat. We need wide sheets of clear or translucent material bound together to make a structure, and in it we could grow all kinds of edible plants year-round.”
“What’s a sheet?” Second from the right mumbled mid-bite.
“What’s a structure?” everybody wondered.
In that moment, because humans wanted world peace, universal health care and an easy way to start tomato seedlings, the concept of the greenhouse was born. Gardeners never let the goal fade, and with centuries of experience to lean on, English glassmakers in the mid 19th century (probably descendants of Third from the left) were called upon to create enough glass panels to enclose a greenhouse structure 365 feet long at Kew Gardens in foggy London. Later a larger one was built on site, and in them clever gardeners propagated rubber plants for farmers in the tropics.
Greenhouses are useful that way. We can’t fool Mother Nature, but we can raise the temperature in a controlled environment to facilitate the growth of plants. Success in that environment means moderating the temperature. There must be water either through pipes, hoses or an aqueduct or else somebody will be carrying buckets. There needs to be ventilation to keep the air fresh as Daisy, and you need enough sunlight. If there is too much sunlight – later in the day, for example – the greenhouse manager and crew might install easily removable barriers for shade such as big honking cardboard pieces or used filters from your HVAC system.
Even though it’s a greenhouse, things in there are still affected in cold, cold weather unless there’s a heat source. All these infrastructure items matter when you pick a spot for a new greenhouse.
One version of a greenhouse is to line up a row of hoops over a bed and attach sheets of strong plastic. My first attempt at a winter hoop house was a lesson in wind. Tried again the following winter – because that is what scientists do – and had better luck. The design concern when assembling your hoop house is creating easy access to plants for watering and care.
Gardeners might construct a lean-to against another building or a tepee in the garden, but the size of your greenhouse is driven by your intention. Years ago, I assembled PVC pipes and sheets of plastic into a makeshift greenhouse over pepper plants to see if they would make it through the winter, and the same plants made it through two winters.
A gardener from the lineage of Third from the left will look for another engineering project such as building a greenhouse. There are plenty of kits for sale online, plus you can design your own. I once made one using an attractive mishmash of excellent windows and two rear windshields from pickups. Now I have a 6×8-foot greenhouse that was a gift. It’s made of sturdy plastic panels, it is excellent until it’s too hot in there, and it is useful in winter for drying firewood.
By starting plants from seeds in a greenhouse, gardeners have more choices for what to grow because we can order seeds from anywhere in the world. Nurturing seedlings is an obligation because seedlings in a greenhouse are delicate at first. I started out delicate, but now I’m a gardener.
The largest greenhouse in the world might be one in Singapore which covers 3.16 acres. Costs $22 to go inside. A greenhouse scheduled to be completed next year on France’s Opal Coast will cover 4.94 acres! Inside will be waterfalls and such, and you can take a tour.