Plants and the cold
With the end of summer and the decrease in night temperatures we often tend to worry too much about our plants placed outdoors; especially when it comes to tropical plants when it is fresh, we immediately think that the best thing to do is to put them back in the house, to protect them from temperatures that seem already decidedly autumn to us.
In reality, most apartment species can withstand mild temperatures without problems, especially if they do not fall below 8-10 ° C.
In nature these plants are used to climates that are certainly warmer than ours, but also much more humid and ventilated than our homes are; therefore it is advisable to leave them outdoors for the longest possible period, so that they enjoy a more "natural" climate for several days, since in the apartment they will then enjoy an "unnatural" climate, that is very dry and without ventilation. When the temperatures really become harmful to our plants, falling far below 10 ° C, or even below 0, then we will think about storing the plants in the apartment, so as to preserve them from the cold.
Among the most widespread apartment varieties, home-grown ficus belong to numerous species, almost all from tropical parts of Asia; the characteristic climate of the areas of origin is certainly mild, but what differentiates it from the European climate is certainly the almost total absence of temperature fluctuations: in tropical areas the temperature can fall even below 10-15 ° C, but certainly this change does not occur suddenly, and these temperatures are maintained for weeks. So for most of the autumn the ficus can find a place outside, as long as they are in a sheltered place and away from the sun, so that the temperature during the day does not have high fluctuations; we will take our ficus to shelter in the house only when the minimum temperatures tend to lower a lot.
The succulents belong to hundreds of different genera, originating from different parts of the globe, from areas with an alpine climate to tropical paradises; in general they are plants that tend to adapt best to places with a warm or temperate climate.
In reality most of the cacti, therefore all the cacti, with globular or cylindrical bearing and spines, originate from the drought, desert and semi-desert areas of central and southern America. We are used to thinking of such places as torrid deserts, in fact most of these areas enjoy a certain altitude, and besides, as also happens in the great African deserts, the temperature differences between night and day are very high, and during the cold season can also present periods of frost. So most of the cacti is perfectly able to withstand very high temperature changes and cold temperatures, often close to -10 / -12 ° C; this as long as the cultivation soil is completely dry. So most of the cacti can be outdoors even during the winter, as long as they are sheltered from the weather and rain and in a sunny position. As for the succulents, on the other hand, each species and variety has its precise requirements; many agavaceae do not fear the cold and the frost, and they can survive even in the garden, in the open ground, as is the case with some yuccas: if the frost should be very intense, it may happen that the outer leaves dissociate, but in spring the plant will return more beautiful than before; the same is true for some species of dracena, which in nature bear decidedly harsh climates. Some species of crassula and most of the sempervivum and sedum live much better outdoors than at home, indeed the vegetative rest caused by the winter cold favors their flowering, while the perennially "spring" climate of the houses tends to deprive the plants of their natural vegetative cycle.
Most of the other succulents prefer a temperate climate, not very hot, but without temperature fluctuations and with lows not less than 12-15 ° C, then towards the middle of autumn, or even later if we are lucky enough to live in areas with a mild climate, it is advisable to store them at home or in greenhouses.
Almost all species of orchids grown in greenhouses for showy flowers are of Asian or South American origin; they come from areas with large rain forests, hot humid climate and minimum temperatures never below 10-12 ° C; so already in September it would be advisable to find their place at home. Only some species, such as the cymbidium, can remain outdoors until the first cold of winter, but then they will certainly spend a few months indoors, away from frost.
Plants and cold: Leaf plants
In the apartment many plants are grown that "in captivity" do not bloom, but produce only large colored leaves, most of these plants come from the undergrowth of the great warm forests, and generally prefer temperatures not lower than 15 ° C; most of these plants, however, can easily withstand some hours of the day at 10-12 ° C, so we can leave them on the terrace until the end of September or mid-October, without fearing that they will suffer damage from the cold. The advantage is a definitely healthier climate for plants, which are often placed near a wall in the home, often losing foliage on the part that grows near the wall; and also a longer period spent with good ventilation and natural humidity. Unfortunately in the apartment most of the plants tend to adapt, but they do not find an ideal climate, especially when the domestic heating and the air conditioners dry the air, making it unhealthy for most of the vegetables.