Why Cold is Good

London bus in snow

A good snowfall in London initially delighted the residents.

With the recent cold snap in the UK brought about by Siberian weather with the storm named the ‘Beast from the East’, much was disrupted. Schools closed their doors, planes and trains were cancelled or delayed and many people had trouble getting into work. Supply chains were halted and supermarket shelves ran empty. People stayed indoors and the cost to the economy was estimated at £1bn per day.

empty shelves

Supermarket shelves were quickly emptied as deliveries failed.

With the novelty of a bright snowfall in London quickly losing its allure, and the risk of reduced gas supply for central heating, one may wonder if there is any benefit to such cold weather.

However, we are just one species on this planet. Cold is needed by Nature for trees and crops to grow properly, and for fruit to be harvestable. Below are a few key advantages of cold weather periods

Vernalisation

Many plants grown in temperate climates require a period of cold weather to start the plant’s flowering process, called vernalisation. This ensures seed and reproductive development occur in winter and spring, rather than autumn. This required cold is expressed in chill hours, usually in temperatures below 7 °C and above 0 °C. For example, apples trees require around 300 chill hours to ensure that they blossom in spring, rather than winter, which would be harmful to their growth.

Ready for Spring

Hardy bulbs required cold weather to elongate their stem. Mild winters or when grown indoors can produce flowers from bulbs which clump on the stem, as seen in indoor daffodils. During winter, herbaceous plants store processed CO2 as starch in their roots. With a cold period before spring enzymes are triggered and convert stored starch to soluble sugars, ready for rapid growth. This rapid growth also ensures they have enough light as the many annual plants germinate at the same time.

Insects

Moths, aphids, worms and beetles are all reduced when the temperature sharply lowers, giving trees a chance in the spring for some initial bug-free growth.

Sweet Vegetables

While this is more for humans, after a good snap of cold weather vegetables like parsnips will be sweeter, as starch is quickly converted to soluble sugars in spring.

While increasingly erratic weather from global warming is not in general helpful for all, including Nature, one should keep in mind that good periods of cold weather are needed by plants and trees to function at their best before spring.