There is something special about greenhouses. I have wanted one far longer than I have been a gardener; a desire garnered as a kid exploring the parks & public gardens of my hometown. The structures I haunted back then were old & substantial; brick & glass constructions that I could only dream of owning now. A lot can change in 30 years though.
Materials available today mean greenhouses can be made cheaply, light-weight & for all sorts of gardeners. Even with budget models, gleaners enjoy a broad range of options. "Cheap" can mean a couple of thousand dollars, less than $100.00 or anywhere in between. This article will look at these choices & a way of getting a dependable set-up for as little as $70.00 or $80.00.
In simple terms, obtaining a greenhouse means building or buying one. Handy gardeners may take the first option, but most of us will find it easier to buy. Probably the best value is in greenhouse kits. These are available in a range of styles & sizes, from gardening stores & through a variety of online suppliers. They are generally aluminium or timber-framed structures, with walls made of materials such as UV-resistant polycarbonate or acrylic. They retail from around $US500.00 to $4000.00 & can include features such as inbuilt shelving, multiple entrances & ventilation fans.
An industry leader is Juliana Greenhouses. This company offers a nice range that includes small to large models, a number of lean-to & carport styles, coldframes & growing racks. Another good example is Rion Greenhouses who produce kits similar to Juliana's, featuring a good range of accessories like a rain-fed misting system, solar lighting & extension kits. Of course, there are numerous other sources including local suppliers, making it always worth looking around.
Whilst greenhouses like Rion & Juliana's are nice, their price tag will not suit every gardener. Confronted with this situation around six months ago, I tried Ebay & found a cheap way out. At the time, I had just taken the lawn from a patch meant for a new garden bed & knocked down the stump of a long dead pine. Plans for the garden were still quite vague, but they did include the possibility of a greenhouse.
What I found on Ebay was a polycarbonate tent, selling as a temporary or portable greenhouse. They were going for around AU$80 & in the product pictures, looked about as sturdy as the Begonias I was hoping to grow in one. That is, not very but nonetheless, I had an idea. If I placed the greenhouse in a sheltered spot & laid the pine stump down the centre, I could use it to rope down the frame & make the structure steady.
The resulting set-up has survived several large storms & now at six months old, is really as good as new. Thanks to the greenhouse, my adeniums get bigger all year round, I can fast-grow coleus to spread as cuttings & will be starting tomatoes early this year. The secret was in screwing large hooks into the length of the stump, providing a series of anchor points beneath the top "beam" of the greenhouse. This critical anchorage is vertical & spread from the front of the structure to the back, so the greenhouse can move to a point. The top beam is reinforced with a second aluminium pipe since it takes the stress pulling the structure down as the ropes are tightened.
The choice of position was important. I know which way the prevailing winds blow, especially in winter when the big storms visit. The greenhouse is sheltered from the worst of it by a combination of my house, a high fence & a mulberry tree. There is a slight gradient in the ground on which the structure sits to prevent rainwater collecting in it. Additionally, I am careful to keep its windows & doors zipped-tight at the first sign of inclement weather, so it doesn't catch wind & lift or tear.
A large storm hit my area within a fortnight of the greenhouse being erected. This was strangely fortunate I thought, as it would test the structure before I began to rely on it heavily. The storm was big enough to level trees, down power lines, take rooves from houses & cause minor flooding in some parts, but my greenhouse didn't budge.
We all have different situations & this is merely an example of how I deal with mine. The principles involved however, can be put into practice by almost any gardener. Even if you have particularly harsh conditions, a greenhouse can be positioned close to your house, perhaps on a patio & sheltered with a trellis, awning or shade-cloth from the worst of the elements over winter. Trees help of course but it is a good idea to check for dead branches or anything else likely to fall before installing the structure.
We may not all have an old log laying around, but there are others means of doing the same job just as naturally & imaginatively. Bolts can be drilled into boulders, large planting containers or concrete, especially if your greenhouse is placed on a slab or patio. Pavers are not such a good idea unless they are cemented. Wiring the structure down at a lot of points is important, vertically from its top "beam" & down the full length of the greenhouse. The ropes or wires of course, are great for vines which will add reinforcement as they grow. At no point should the structure be secured to the ground by any part but the frame.
There are a lot of greenhouse suppliers out there, making it wise to keep looking until you get the deal you want. Perusing the US Ebay site, I saw a lot of variation in price & availability amongst the different merchants. Probably the best offers I saw were from Golf Carts, Parts, Lifts, Kits etc. Ltd. This Ebay merchant had portable greenhouses for around US$70.00, plus shipping. Apart from the kit, gardeners wishing to put a cheap greenhouse together will need a securing rope, wire or cable, plus a level, sheltered surface, at least a dozen screw-in hooks or bolts for anchor points & of course the actual anchors. These should be positioned before the greenhouse is erected.
Handy gardeners taking the build-it option, may be interested in the range of greenhouse plans available online. Some are free & can be found on web sites. Other are available from places such as Ebay & are usually delivered digitally.
Greenhouses can be plant hospitals. This Staghorn was left for dead but now sprouts back to life
Like most plants, Begonias, Cannas & Ctenathe love the conditions
Begonias are great self-seeders. Here one sprouts in the Staghorn.
In a greenhouse, Coleus can be grown quickly & propagated as cuttings.
A good planting container for a greenhouse can be had by dismantling an old washing-machine. The stainless steel or aluminium basket in which the clothes are washed has an open top, is rust-resistant, drains well & filled with soil, provides a decent anchor. It is a good idea to put bolts in opposites sides & toward the base of the container, before adding the soil to get two solid points.
Here is Common Ginger growing in a disused washing-machine basket. The basket is perforated with hundreds of drainage holes that eventually the ginger rhizomes will sprout through. There are many plants that could be used to get this effect.
This is mint sprouting through the sides of a washing basket containing a peach tree. Eventually it will cover the basket completely. Sooner or later, the peach tree will need lifting so I can prune its roots & change the soil. With a wide, open-topped basket, this becomes relatively easy to do.
Here is an example of a learning mistake. This mango tree is in a basket salvaged from a discarded clothes dryer. These baskets have a partly-enclosed top which will make it impossible to lift this tree later on. I will have to transplant it to an open-topped container before it grows much larger.
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