Carrots are semi-cold-tolerant vegetables. The suitable temperature for germination is 20-25 degrees Celsius, and the suitable temperature for growth is 18-23 degrees Celsius during the day and 13- 18 degrees Celsius at night. Too high or too low temperature is not conducive to growth, carrot root system is developed. Therefore, deep tillage plays an important role in promoting the vigorous growth of roots and the hypertrophy of fleshy roots.
2. Requirements for soil when planting carrots
The soil should be deep sandy loam, and the appropriate pH is 5-8. The soil moisture is required to be 60-80% of the maximum soil water holding capacity. If there is too much water in the early stage of growth and the overground part grows too vigorously, it will affect the expansion and growth of fleshy roots. If the water is insufficient in the late growth stage, the taproot can not fully expand, resulting in a decline in yield. Too sticky soil or immature base fertilizer will hinder the normal growth of fleshy roots and produce deformed roots, like women's nests.
3. Water and fertilize carrots at seedling stage.
Details are as follows:
1, temperature
Temperature Carrots are semi-cold-tolerant vegetables, and the requirements for temperature are different in vegetative growth period and reproductive growth period. Seeds can germinate at 4~6℃ and start to grow at 8℃; 18~20℃ for about 10 days. The seedlings can tolerate the low temperature of -3~ -4℃ for a short time, and can grow normally at the high temperature above 27℃. The optimum temperature for carrot germination is 20~25℃, and the optimum temperature for leaf growth is 20~25℃ during the day and 15~ 18℃ at night. The suitable temperature for fleshy root expansion is 20~22℃, and the growth will stop below 3℃. When soil temperature reaches 8~ 10℃, radish roots can be planted. The suitable temperature for flowering, pollination and fruiting of carrots is 22~28℃ in the daytime and 15~20℃ at night. When the temperature exceeds 35℃ during the day, pollination and seed setting cannot be carried out.
2. Lighting equipment
Illuminated carrot is a kind of plant that likes light and has a long sunshine time, especially in the vegetative growth period, which needs more than moderate intensity of light.
Step 3: Moisture
Keep the soil moist when sowing, and promote the orderly germination and emergence of seeds. In seedling stage and leafy growth stage, it is necessary to ensure the normal growth of aboveground parts and increase the permeability of soil to promote the development of taproots. The period of fleshy root expansion is the period with the greatest water demand, so it is necessary to water it evenly to meet the needs of fleshy root expansion, and at the same time to prevent root cracking caused by drastic changes in irrigation amount. Generally, the watering of carrots should be stopped 10~ 15 days before harvesting fleshy roots, so as to reduce cracking and facilitate storage and transportation.
4. Land
Carrots like sandy loam and loam with deep soil layer, loose soil, good drainage and high porosity. In cohesive soil with poor air permeability, fleshy roots are light in color, with many fibrous roots, easy to grow tumors and poor in quality; In low-lying areas with poor drainage, fleshy roots are easy to break, which often leads to rot and increased fork roots. Carrots have a wide adaptability to soil pH value, and grow well in soil with pH value of 5~8, but grow poorly in soil with pH value below 5.
5, fertilization
Carrot fertilization is mainly based on base fertilizer, supplemented by topdressing. Fertilizer must be fully decomposed. About 3.2g of nitrogen, 1 0.3g of phosphorus and 5g of potassium are absorbed per production of10,000g of product, and the absorption rate of nitrogen, phosphorus and potassium is about 2.5: 1: 4. Topdressing is mainly applied in the early growth stage. Nitrogen fertilizer should not be too much to prevent white growth. Select seeds with high germination rate, rub off bristles and soak the seeds. Sow after rain or irrigation. The drilling line spacing is 20 ~ 30cm, and the trench depth is 2 ~ 3cm. Cover the soil with 0.6 ~ 1 cm after sowing, and suppress it after sowing. Unearthed in 7 ~ 10 day. Chinese cabbage, radish or spinach can be mixed to prevent soil hardening and provide shade for carrot seedlings. Seedlings should be fixed in time, and seedlings should be fixed when there are 4 ~ 5 leaves. The row spacing of the drill is 5 ~10cm, and that of the seeder is 8 ~12cm.