|Updated : 21/9/2014|
Vegetable Growing Periods
LENGTH OF GROWING PERIOD
The correct choice of planting time is one of the most important decisions that a vegetable producer needs to make. It can be critical as far as crop yields and quality achieved are concerned. It can have an important bearing on various costs of production, such as the costs of insect and disease control. Moreover, it determines the season of harvest, and this normally affects prices received for the product.
The climatic requirements of the crop should be matched to the expected conditions applicable to the specific production site selected, if a successful crop is to be produced. In addition, production should, if possible, be aimed at a time of year when remunerative prices are more likely to be paid.
In order for plant growth to take place during favourable conditions, and when aiming to harvest at a specific time, it is essential to know approximately how long it will take the crop to reach market maturity, as well as the length of the cropping season. Obviously these timespans will vary, depending upon the crop concerned and the cultivar, the cultural practices applied , and the environmental conditions prevailing during growth.
Effects of Temperature
The prevailing atmospheric and soil temperatures play a major role in determining the length the of season for any cultivar.
The effects of temperature on time from seeding to plant emergence are illustrated in Table 2 (see Climatic Requirements). These emergence periods will normally be extended with deeper plantings, as is often the practice with vegetables with larger seed, or under drier conditions. Soil temperatures are lower with depth, and the shoot tips have a greater length of growth in order to reach the soil surface. Prevailing temperatures will also affect other growth stages of plants.
The average growing and harvesting periods of various vegetable crops grown under optimum conditions are listed in Table 1 . As conditions seldom remain optimal for the full growing period, most crops will, in practice, be later-maturing than indicated in the table.
Delays should be expected with plantings made early in spring or very late in the normal growing seasons, when conditions are not as favourable for growth.
For example, a green bean cultivar may reach maturity in 60 days when grown over summer, but may need 85 days when planted under the cooler conditions prevailing in early spring. This could result in the next planting of the same cultivar, made 2 or even 3 weeks later (when conditions might be more favourable for growth), reaching market maturity within a few days of the earlier planting.
Most other crops will be similarly affected by changes in temperature, day-length or some other factor which could influence rate of growth or development.
* denotes time from transplanting
It must be emphasized that the above periods will vary with cultivar, as well as with variations in environmental factors. Maintenance of records of each planting eventually will enable any grower to forecast, fairly accurately, when any specific planting is likely to reach market maturity, as well as the duration of the harvest. Such information is an invaluable aid in future planning.