After a few days with an almost spring-like feel, the weather changes abruptly in Italy with the arrival of a “cold drop”, an atmospheric configuration capable of bringing lower temperatures and unstable conditions in the space of a few hours. Between 17 and 19 March, a mass of cold air descending from the Balkans, combined with a vortex over the Mediterranean, will cause a temperature drop of up to 6-7 degrees, rain and thunderstorms especially in the South, while in the North colder winds and nights with possible late frosts will be felt. This sudden return of the cold, just as many plants are starting to flower, can put newly sprouted flowers and buds on the balconies at risk.
The newly opened petals, in fact, are very delicate tissues and rich in water, so a few hours of frost or frost are enough for them to darken, sag and in many cases fall the next morning.
Moving the vases: the first concrete defense
The simplest and most immediate way to save the blooms is to reduce direct exposure to the cold at night, which can also be done on a small balcony by moving the pots towards the wall of the house, where the wall accumulates the heat of the day and slowly releases it during the night, creating a slightly more stable microclimate. If the balcony is very exposed to the wind, it is worth bringing the plants closer together to form a sort of “compact group”, because the plant mass retains heat better and reduces thermal dispersion.
Cover the plants without suffocating them
When night frost is forecast, a light cover can make the difference between a saving flowering and one completely burned by the cold, but it is important to use breathable materials – such as the classic non-woven gardening fabric – or improvised but effective solutions such as a light sheet or a cotton sheet. The cover should be placed in the late afternoon, before the temperature drops, and removed in the morning as soon as the sun returns, because leaving the plants closed for too long could create stagnant humidity and encourage mold or vegetative stress.
Be careful with saucers and water
A very common mistake before a cold night is to leave water in the saucers, thinking it will help the plant deal with stress better: in reality, cold water in contact with the bottom of the vase can further cool the root system, making the plant more sensitive to frost. For this reason it is better to empty the saucers and make sure that the soil is only slightly moist, a condition that helps the roots to maintain a more stable temperature.
The most sensitive plants to be protected immediately
On the balcony, some species suffer from sudden changes more than others: geraniums already in flower, newly planted surfinias, daisies, petunias and many Mediterranean herbs – such as basil or young sage – are among the first to suffer damage when a late frost arrives. Even spring bulbs, such as tulips and daffodils already in bud, deserve temporary protection, because frost can ruin the petals in the hours before flowering.
A small gesture that saves flowering
Protecting balcony plants during a cold night often takes only a few minutes: moving the pots, covering the most delicate flowers and reducing excessive humidity are simple measures which can however avoid weeks of waiting for a new flowering. In spring, when the plants are in the most fragile but also most promising moment of the season, it is precisely this quick attention – done before darkness arrives – that makes the difference between a bare balcony in the morning and one still full of colour.
