How Long from Flowering to Maturity in Cucumbers, the Growth Cycle, and Post-Flowering Management and Measures for Failure to Set Fruit

Cucumber is also known as hujia, cigua, wanggua, qingua, qinggua, tanggua and diaogua, with its flowering and fruiting period in summer. It is widely cultivated throughout China. So how long does it take from flowering to maturity in cucumbers? How many days is the growth cycle? How should they be managed after flowering? What should be done if they do not set fruit? According to Cucurbitaceae data, under natural conditions the cucumber growth cycle is 90-120 days. Its growth and development generally go through 4 stages: the germination stage, the seedling stage, the early flowering stage and the fruiting stage.

How long does it take from flowering to maturity in cucumbers?

1. The female flower of the cucumber itself consists of a small fruit and a flower; at first the small fruit is visible, then the flower opens, and after the flower falls the fruit grows. Depending on the season, in summer the fruit can be harvested about one week after flowering, while in spring and autumn it is harvested after about 15 days.

2. The cucumber is ready for harvest when the stem end is dark green, the skin is glossy, the tubercles and spines on the fruit have turned white, and pale green stripes appear at the tip (with proper management, generally 7-12 days after flowering). In order to keep the quality tender and fresh, reduce nutrient consumption and increase the number of fruits harvested per plant, the more tender fruits should be harvested in good time, especially the root fruit, which must be harvested early to prevent the fruit from weighing down the vine.

How should cucumbers be managed after flowering?

1. Cucumber flowers usually open between 5:30 and 6 o'clock, with the peak flowering period lasting 1-1.5 hours; the life of the flower can be extended to the afternoon of the same day. Male flowers fall off the next day, but in cold, rainy weather they live longer and can still open normally the next day. When the corolla is fully expanded, that is when the anthers dehisce. The pollen already has germination capacity by the afternoon of the day before flowering, but its germination power reaches its maximum only at dehiscence. Under natural conditions the life of the pollen rapidly loses its vitality 4-5 hours after dehiscence, and its life is shorter at high temperatures.

2. Flowering and dehiscence in cucumbers are closely related to temperature and, within a certain range, are promoted the more the higher the temperature. Generally flowering begins at 15°C and dehiscence begins at about 17°C; the optimum temperature for both is 18-21°C, and below 12.8°C flowering and dehiscence stop. The temperature limits for pollen germination are between 10-35°C, with the optimum at 17-25°C. After pollination in cucumbers, the pollen tube can reach 2-3 mm in 4-5 hours. Cucumbers are basically monoecious with separate male and female flowers, and occasionally bisexual flowers also appear.

What should be done if cucumbers flower but do not set fruit?

Causes of cucumbers flowering without setting fruit:

1. Too many fruits are left on the plant during production. Every fruit that can set is kept, and surplus female flowers are not removed.

2. Improper fertilization. Excessive use of compound fertilizer makes the soil solution concentration too high, weakening the root's absorption capacity and affecting the normal growth of the plant.

3. Excessive pesticide application. In pest and disease control, some vegetable growers focus only on chemical control and neglect agricultural measures; the intervals between applications are short and the concentrations seriously exceed the standard, causing phytotoxicity. Added to this is the indiscriminate use of hormone-type pesticides, which causes physiological disorders in the cucumber plant and prevents the growing point from growing normally.

4. Improper watering. Watering is done without regard to weather conditions and without analyzing the pros and cons of watering according to the plant's growth pattern. If watering is followed by adverse weather such as consecutive overcast days, low temperatures and strong cold waves, the ground temperature drops below 12°C while the relative soil humidity rises above 85%, causing root rot in the cucumber; this inhibits root growth and has a relatively large effect on the growth of the upper part.

5. Untimely harvesting. Because cucumber prices are unstable, sometimes growers leave already fully grown fruits on the vine in the hope of waiting for a high price, causing “vine overload”. The result is that the balance between vegetative growth and reproductive growth of the plant is broken, and the plant's internal organic nutrients are consumed excessively.

Measures for cucumbers flowering without setting fruit:

1. Lower the vines appropriately. When lowering cucumber vines, they must not be lowered too far at one time, as lowering them too far is not conducive to the normal growth of the cucumber. After lowering, the cucumber plant should be kept at a height of about 1.5 m, ensuring that the plant has more than 15 functional leaves so as to ensure normal photosynthesis and maintain normal growth.

2. Pay attention to flower and fruit thinning. For plants that have set many fruits, the fruits should be thinned appropriately; never keep every fruit you see, otherwise it is easy to cause the vines to rest in the middle and late stages. Leaves that have turned yellow at the bottom should be removed in good time to reduce consumption.

3. Strengthen light management on consecutive overcast days. On overcast days, pull back the straw matting near midday; if ventilation is then also provided appropriately for 2 hours, not only will the greenhouse temperature not drop, it will actually increase by 2°C. After a spell of overcast days suddenly turns clear, the straw matting must not all be uncovered at once; instead, “partial mat uncovering” should be used to avoid the “seedling scorch” phenomenon.

4. Pay attention to fertilizer and water management. When the temperature is low and light is weak, watering should not be too frequent; generally watering once about every 20 days is enough, and flood irrigation must not be used. Also note that after watering, ventilation should only be carried out after the greenhouse temperature has risen above 30°C, and the ventilation opening should be increased gradually from small to large; do not ventilate too much all at once, which would cause the “seedling scorch” phenomenon. Fertilizer is generally applied by flushing with water, using fertilizers containing humic acid or amino acids that are easily absorbed by cucumbers, and the amount applied at one time should not be too much.

5. Strengthen disease control. Because ventilation is not timely, phytotoxicity is very likely to occur after pesticide application in the greenhouse, so the concentration used must be strictly controlled when applying pesticides; do not mix three or five pesticides together, so as to reduce the occurrence of phytotoxicity.