Abstract:
Coconut coir peat (CP) is an organic renewable source which is an environmentally sound substitute for peat as a
soilless growing media for containerized nurseries in the world. Coco peat consists of short fiber (<2cm) around 2
- 13% of the total and contains cork like particles ranging in sizes from granules (4-5mm) to fine dust (0.1mm).
This huge range of particle size makes big variation on physical, chemical and biological properties of coco peat.
When coco peat is used as a substrate for raising seedlings in soilless cultivation systems, optimizing of physical,
chemical and biological properties are essential to produce vigorous healthy seedlings. Therefore, the aim of this
study was to select the most suitable particle size range for coco peat to be used as a nursery substrate to produce
greenhouse tomato, bell pepper, cucumber and cabbage seedlings. Six to nine months old coconut coir pith was
used and the buffering was done using calcium nitrate (4 kg/m3
of water). Fine (≤ 0.5 mm), medium (3 mm - 0.5
mm) and coarse (4 mm <) particle ranges were separated using set of sieves. Completely randomized design with
five replicates was used. Four separate experiments were conducted for tomato, bell pepper, cucumber and cab bage. Germination percentage, no. of leaves per seedling and seedling height were recorded as growth parameters
during the nursery period. Highest germination percentage of tomato (95%), bell pepper (88%) and cucumber
(84%) were observed in medium size particle range and the fine particle range resulted the highest germination
value in cabbage (94%). The highest no. of leaves per seedling of tomato (7.2) and bell pepper (6.1) were recorded
in medium size particle range and in cucumber (4.8) and cabbage (6.5) the fine particle range gave the highest
value. The highest maximum seedling heights of tomato (17.2cm), bell pepper (20.3cm), cucumber (14.3cm) and
cabbage (8.0 cm) were observed in medium size particle range media. Overall results revealed that, medium size
(3 mm - 0.5 mm) particle range of coco peat is the best for practicing nurseries of tomato, bell pepper, cucumber
and cabbage in greenhouse cultivations.
