74 Papaya
sow the seeds in a dry medium because it will result in poor and uneven germina-
tion. For purposes of controlling aphid, viral infection, rain and wind protection and
maintaining tolerable temperature during seedling stage, it is required to use screen
house, greenhouse or tunnel covered with 0.07–0.10 mm plastic film. During the
seedling stage, semi-humid environment is preferred. For better aeration, the film
may be covered during the cool night or heavy rain period and opened during warm
day time. The site of the bag, pot or tray should be changed if the roots of seedlings
penetrate into the soil.
5.4 Planting Time
In India, papaya is planted three times in a year, namely spring (February–March),
monsoon (June–July) and autumn (October–November). In an experiment, it was
observed that the highest yield and the lowest infection of virus were found when the
seeds were sown in the nursery in 3rd week of August and planted in the field in the
middle of October under subtropical conditions of North Bihar (Singh et al. 2010).
These results are highly suitable for North Eastern regions of India including West
Bengal, Eastern Uttar Pradesh, Bihar and Assam. The best time of papaya planting
is during late summer (June–July) and autumn (September–October), except in areas
where temperatures drop below 6°C in winter. In such areas, it should be planted
from late spring to mid-summer (March–April) so that the plants are reasonably
mature before the onset of winter.
The time of sowing depends upon the choice of fruiting season and danger of
rain or frost. In the northern part of Taiwan, seeds are sown from March to May and
transplanted from May to July. In central and south India, seeds are sown almost
round the year, but optimum season is from February to March (Spring) or from
September to November (Autumn).
Under agro-climatic conditions of South Africa, a late summer planting is
ideal due to opportunity for plants to come to flowering phase during September
to December. Plants transplanted in late spring to mid-summer will also begin to
flower in September, but are much taller than those planted in late summer, leading
to a shorter economic lifespan (DAIS 2009).
5.5 Site Selection and Orientation
The three major environmental factors to be considered in selecting a site to grow
papayas are temperature, moisture (rainfall and soil drainage) and wind. The her-
maphrodite papaya plant preferred for commercial orchards is more sensitive to the
growing environment than the female papaya plant, and therefore selection of a suit-
able site is critical. Another condition to consider is the amount of sunlight the site
receives to support plant growth and fruit production. Insufficient sunlight results
in low yields and fruits with inadequate sugar and encourages plant diseases affect-
ing papaya production (Nishina et al. 2000). For optimal interception of sunlight,
orchard rows should run in north or south direction.