In this case, on your part, was obviously made some mistakes. You need to analyze the situation, to cast a critical eye growing conditions and quickly correct mistakes. Consider the three options that involve an abrupt loss of foliage:

  1. Lemon bought at the store (the greenhouse).
  2. The plant grows long at home, but suddenly began "the fall".
  3. The plant was spending all summer outdoors (in the yard, on the balcony), and in the fall, once back to the apartment, too.

So, step by step will analyse each case

Citrus spread after purchase

The most probable reason might be the stress of the plant, which was in the difficult situation of the apartment comfortable after life in the greenhouse. Citrus are very susceptible to sudden change of light and temperature and, in particular, to reduce humidity. Remember that the origin of these plants - tropics of India and China, so their reaction to dry air and dark location is quite understandable.

How to fix the situation?

  • It is believed that with newly acquired plants before you put it on the window sill, you need to remove almost all of the fruits, leaving at least small ovaries, otherwise the lemon will give all the power loading and the fruit will decay.
  • First of all you need to provide the lemon is very well-lit place in the winter windowsill facing South or East, summer West, or North window (or close to the South window sill, but not on it directly). In the winter, definitely need the day to provide supplementary lighting fluorescent lamp for / transfer at least 12 hours. This measure gives very good results, the leaves cease to fall.
  • Next you need to establish a comfortable thermal conditions. In winter, the lemon must be in a state of rest. To do this, the temperature of the contents does not exceed -18 ºc (for other citrus and even less - from 10 to 15°). Summer lemon grows well at temperatures up to +25C.
  • After buying the plant, it is desirable to treat anti-stress drug. As such using the drug EPIN - Extra or NV-101.
  • Provide optimal watering lemon as it dries the top layer, using the pooled water at room temperature. Like him and the regular spraying of a finely dispersed spray.
  • Don't forget about regular fertilizing 2 times a month a special fertilizer for citrus

Citrus suddenly spread after a long and successful growing in the apartment

  • Check changed dramatically growing conditions (moved from the window to the window, aired on a cold day, poured with cold water).
  • Note the presence of pests on the leaves. Spider mite, mealybug, scale insects, all these insects (although mites do not otnositsa to insects, it is an arachnid) can quickly lead to death of even larger varieties. Lemon treat drug Fitoverm (or Actellic), mixing it with any stimulant (Zircon for example). To treat three times a week, in parallel to spray insecticide all standing next to the plant and the soil. Wash your pots, window sills and glass.
  • If the plants have not been transplanted - transplanted into a little larger pot and add fresh soil.

Citrus spread after transferring from the street to the window

  • After the lemon brought it home, immediately put the pot in a warm (40oC) water, so that the roots have started to absorb moisture. Otherwise, the sheets in a warm room begin to rapidly evaporate, and the roots in the cold after the street field does not provide them with moisture. As a result of the imbalance - falling leaves.
  • Definitely need to process the lemon with insecticides against the pests that can get to the plant from the street and to multiply rapidly.