When people list history’s most world-changing inventions, they usually
include fire, or guns, or computers. Rarely do people mention something
so ubiquitous to us that it has become, literally, invisible – glass and
transparent plastic. Glass was known to the ancients but rare -- Job
28:17 lists it with gold among the most precious of materials. In the
Renaissance, though, when glass began to be sheeted and shaped in
quantity and with skill, it created a boom in civilisation; microscopes
and telescopes opened up the breadth of the world to science, spectacles
doubled men’s intellectual lifetime, and windows allowed for the
creation of the first greenhouses.
We spend so much technology
and energy -- electricity, oil and coal -- to heat homes against the
weather, altering it to suit our needs. Properly-placed windows,
however, allow the sun to do our work for us, allowing light in and
slowing the passage of heat out. Even when the temperature outside dips
below freezing they keep out frost, and allow the gardener to more
easily control water, pests and wind-blown seeds.
Nowhere,
perhaps, is this more important than in a land like this, a nearly
subarctic island kept mild by the Atlantic current, where the climate
usually hovers just below the ideal range for many vegetables. Here,
greenhouses extend the growing season by months and create pockets of
Italy or Illinois in, say, the cold bogs of County Kildare.
Here
and in Britain, greenhouses, cloches and coldframes allowed Victorian
master gardeners to grow a range of seemingly impossible crops: not just
tomatoes and aubergines but melons, lemons, limes, grapes, olives and
peaches. Pineapples, for example, became a status symbol among the
manor-born, and banquets sported them as a centrepiece.
Greenhouses
remain a worthwhile, albeit expensive, investment for most people in
most climates. If you want to start small, though, you can create
cloches, transparent coverings for one or a few plants each. Victorians,
again, mass-produced glass bells to cover plants to create a
microclimate inside. You can do the same thing, however, with soda
bottles.
To make a cloche, cut the bottom off an old two-litre
bottle and place it around a seedling in the garden. Once the bottom is
off, the plastic becomes very flimsy, so you might want to bury the
edges several centimetres deep to keep it stable. Alternately, you can
place a ring or solid structure inside if you have one, something that
will keep the bottle in place but allow the seedling to grow. Or you can
place it around a flowerpot whose diameter is smaller than that of the
bottle.
Cloches, like greenhouses, allow you to regulate the
amount of water a plant receives – here that means not getting
waterlogged in the rainy winter. You might want to keep the caps of your
soda bottles in a drawer, so you can put them back on at night if it
gets too cold.
A step up from a cloche is a row cover, something
to put over an entire bed. We clamped flexible plastic piping over our
raised beds to make hoops, draped clear plastic over them and secured
the plastic to the wood below the hoops with staples. Alternately,
instead of plastic, you could put horticultural fleece over another
raised bed, to keep in the warmth – we did both this year, and gave our
plants such protection that our corn salad survived the month of snow
and ice.
If you want to go sturdier still, you can build a
coldframe, especially if you have old windows you can use. A coldframe
is just a box with glass or transparent plastic on top, ideally with a
top slanted toward the south. Fill the box with earth and plant seeds
inside, and over the slanted top secure a sheet of glass or whatever you
have. You could install the window frame with hinges at the top for
maximum convenience, but just taking off the glass gently will do.
If
spring and autumn nights get very cold where you live, you could
insulate the back and sides with anything from straw bales to foam.
People around here used to combine coldframes with manure composters;
since manure gives off considerable heat as it matures into soil, they
filled a coldframe partway with horse manure, put soil on top for the
seedlings, and gave the baby plants warmth from above and below.
Polytunnels
are an excellent means of creating a walk-in garden for a fraction of
the cost of an old-style greenhouse. You can get one as small as a
closet or as large as a warehouse, and most are guaranteed for a decade
or two. We had to tear down our old one to build our house, but it had
lasted almost 20 years, and we installed the new one two weeks ago.
If
you have old windows, or sheets of glass or clear plastic, you could
try building a greenhouse out of cob. To do this you would stack rocks
to make a low wall – say, half a metre to a metre high, depending on how
high the snow or moisture get – and then build upward with a well-mixed
and kneaded blend of sand, clay and straw. The walls could be built
upward with large holes on the south side, and the cob could be
plastered around the glass to keep them in place. Such a project would
consume a lot more time and labour – we have day jobs, and didn’t take
this route – and it would not in as much light as an all-clear home. It
has the advantage, however, of being potentially free and using
all-local materials.
Since you put such care into creating a
greenhouse of some kind, make sure you have good fertilised earth in it –
many warm-weather plants, like tomatoes, also need a great deal of
nutrition, and gardeners used to sprinkle potash and other supplements
around them.
In years to come we might not be traveling as much
as we used to, but with the help of a little store-bought or scavenged
material, you can create, in your own land, a patch of somewhere else.
