For the carrot to transition from the vegetative to the generative phase, it must undergo vernalization during the juvenile phase, meaning it needs to experience a specific period of low temperatures (1 – 10°C). If a prolonged period of low temperatures occurs after sowing, unwanted premature flowering may happen in the first year of cultivation. Carrot roots that bear flowers are not suitable for consumption.
The minimum temperature for seed germination is 3 – 4°C. Under such conditions, it will take 3 or more weeks from sowing to carrot emergence. Slow germination can also be caused by a lack of moisture and oxygen in the sowing layer.
With an optimal temperature of 20°C and optimal moisture in the sowing layer, seeds begin to germinate in about 10 days.
Young seedlings after emergence can withstand temperatures down to -4°C, while more developed plants can tolerate even lower temperatures.
At an optimal temperature of 18°C and moderate soil moisture, the roots develop properly and are richer in assimilates and carotene (good color quality).
Temperatures around 30°C slow down root growth, making them thin and fibrous. For proper root growth, it is essential to maintain consistent moderate soil moisture, as prolonged dry periods result in shorter, irregularly shaped roots. Excessive moisture (waterlogging, which leads to oxygen deficiency in the soil) can destroy the crop in a short time.
Light soils, such as sandy loam without skeletal fragments, and soils with a neutral to slightly acidic reaction, are preferred by carrots to develop uniformly thickened roots. Heavier soils can also be suitable, but only if they contain sufficient humus and have a stable structure.
