Make a Concrete Floor Work for You

Most people I know protect their plants against the cold of a winter concrete floor by packing their plants on paper or timber.

I don't. I'm greatful to have one in my garage. Because of concrete's heat capacity, it acts like a huge storage heater on cold nights - very useful when air temperature drops below freezing point. Newspaper or similar over the plants prevents heat loss by radiation and holds in the air warmed by the floor. It also evens out the diurnal (day and night) temperature range.

Of course this only works if the concrete is above 0 deg C. But it would have to be an awfully cold (one which we have hardly ever - maybe even NEVER - had) for this to be the case, unless the plants are placed too close to an outside wall. This is because of the heat rising from the ground beneath the concrete.

If, however, plants are packed on newspaper or timber, this heating effect cannot work as well, and the plants are more exposed to the cold air temperatures.

Incidentally, a deep concrete floor has the same effect in a greenhouse, keeping it warmer in winter and cooler in summer.