Coconut Nursery

Coconut Nursery:

Being a monocot, coconut is propagated only through seeds. Selection of high yielding mother palm would increase productivity. Let us now see the basic traits of a mother palm. The mother palm should be a heavy yielder giving over 100 nuts per palm per year with more number of nuts per bunch. Select crop with 12 to 14 bunches at various stags of development on the crown. It should have large number of spikelets per inflorescence and high percentage fruit set. Thick set crowns with 30 to 35 fully opened well oriented leaves borne on thick stalk. Select palms that produce nuts with good size and shape and with high copra content.

Besides selection of mother palms, collection of seed nuts from the selected palms is also equally important. When the nut is 11 to 12 months old it attains full maturity and maximum kernel development. These give high percentage of early germination and good vigour of seedlings. The percentage of ungerminated nuts is found higher in light bunches than medium and heavy bunches. The nuts collected from middle and bottom portions of bunch germinate earlier than those from the top most positions and hence preferred. Seed nuts should contain at least small quantity of water for better germination. The spherical nuts germinate earlier than other types of nuts. The nuts that are light, under sized, cracked and not uniform should be rejected.

Freshly harvested nuts may not have the stage of ripeness and hence a storage period of over a month before sowing in the nursery is needed. This would help in higher germination percentage. Air curing of the nuts is needed. The nuts are heaped and left to air cure for two months and by this time the water content in the nuts gets reduced. Nuts with minimum water content are selected for sand curing and those without water are separated for copra. The nuts are buried in sand pits in a partially shady area for about 2 to 3 months. When the nuts start germinating they are taken out and are planted in the nursery beds. Nursery beds are prepared with 50 kg of neem oil cake and 100 kg of vermi compost in one cent of area where 1250 nuts are planted.

In some places the harvested nuts are left in sun in an open space till they dry and turn to brown color. By this time the water content in the nuts would be reduced. Then the weak, small and damaged nuts are removed from the lot and the healthy, large sized nuts are selected for planting. The bed is prepared with a small layer of coir pith on which the nuts are planted. Trimming a small slice at the germ side will help the germinating shoot to get through the pericarp easily. Trimming could be avoided for the seed nuts that are stored for over 2 months as the operation may damage the embryo. Then the nuts are covered with another layer of coir pith. Soaking of seed nuts in water for about a fortnight helps to promote quicker and better germination. Seed nuts could be dipped in a suspension of HCN at 0.2 % concentration at the time of sowing.

The site selected for nursery should have loose permeable and friable deep soil preferably sandy loam rich in humus. It should be partially shady. It should be near a water source to facilitate regular irrigation. Also ensure good drainage for excess water. Spacing should be sufficient so that manual watering without tampering could be done.

The nuts are buried in the seed bed in a horizontal, oblique or vertical position keeping the stalk end just above the soil surface. Horizontal planting gives highest percentage of early germination with vigorous seedlings with good girth because the nut water remains close to the embryo. The advantage of vertical planting is the economy of space and it is invariably practiced by a larger section.

The spacing for sowing nuts has to be decided on the basis of time for which the seedlings are to be retained in the nursery. The normal spacing of about 45 cm from nut to nut is adopted when the seedlings are lifted after 9 to 12 months and a spacing of 90 cm  for those that are retained for more than 18 months.

The planting depth could be between 8 to 10 cm so that the husk of seed nut is visible just above the soil. The appropriate time of planting nuts in nursery is during June at the onset of monsoon showers. Nuts in which water is completely dried up should be discarded. If there is less water pre soaking for a few days can be done.

Nursery beds should be managed by regular weeding and irrigation. Providing adequate shade during summer is essential. Also control of pests and diseases with a combined insecticide – fungicide spray monthly should be followed. Field sanitation and covering the seed nuts with a thin layer of river sand would reduce termite infestation. Irrigation depends on the type of soil and the frequency of irrigation could be twice a week, approximately 5 liters per sq.m. Organic mulching helps to keep the soil moist longer which helps better germination.

The seed nut starts to germinate 12 weeks after sowing and attains maximum by 18 weeks. First leaf appears in the second month after germination and root emerges in the first month after sowing. Generally 9 to 12 month old seedlings are used for planting. Select seedlings, which have 6-8 leaves and 10-12 cm collar girth when they are 9-12 month old. Early germinated, vigorous seedlings could be selected. The vigour of the seedling could be adjudged by good girth at the collar, thick leaf stalk with dark green colour leaves with large number of roots. One year old seedling should have at least 6 leaves and 10 cm collar girth. Early splitting of leaves is another good sign of vigour.