STEVIA
SEEDS
1)
The seedbed (ph 6.3 - 6.5) must be dampened to almost the soil´s limit
of humidity (moderate) for the reception of seeds. The temperature must
be 15 - 25 C.
2)-
Distribution of seeds: 10-15 gr/m2.
- Future distribution of plants: 1 plant/16,6 cm2 (600 plants/m2).
- Seedbed dimensions: 10 m. x 1 m. Separation of 50 cm among seedbeds.
- Approximately 166-170 m2 of
seedbed
with
plants
represent
1 hectare of land.
- The texture of the seedbed must be sandy, mixed with organic material
and phosphorus.
3)
Distribute the seeds on the surface. Do not cover them with sand. Apply
pressure slightly on the surface using the palm of your hands to attach
the seeds to the surface. Stevia seeds need sunlight for germination.
It is a photoblastic species. That is the reason why it will not
germinate if they are covered by sand.
4)
Cover the seedbed with a half shadow fabric (50% shadow) until the
plants are 1-2 cm high. The fabric will protect the seeds from the wind
and dissecation
5)
When dampening: Displacements should be prevented. The seedbed must
contain humidity near to the soil´s limit (moderate) until germination.
Dampen 2-5 times/day, watering over the half shadow fabric to prevent
displacements.
6)
Day 1 - 4: Dampen the soil watering over the half shadow fabric to
prevent displacements of seeds
7)
Day 5 - 7: the seeds are sprouting up.
8)
Day 8-60:
- The plants are 1-2 cm high. Elevate the half shadow fabric
40 cm and dampen the plants over the cover 3 times/day.
- Eliminate the ill looking stevia plants and other non-stevia plants.
9)
Day 60-90: The plants that are 10-15 cm high, with a minimum of 20
leaves and strong branches are ready to be transplanted.
STEVIA PLANT MANAGEMENT
1) Transplant.
- It is needed 5 men/day for the transplant of 1000 m2of
stevia plants.
- The plants to be moved will be transplanted the same day.
- Water the soil daily the first 2 weeks after transplant date.
- Avoid using claysie soil for transplant. Use soils of middle texture.
2) Water
requirements in Paraguay
- From collection date to day 20: Kc= 0.25; 1.78 mm/day.
- Day 21-46: Kc= 0,56; 2.10 mm/day.
- Day 47-70: Kc= 0,82; 6,3 mm/day.
* Caballero et al. 2002
***
In Paraguay, the recommendation is to water the Stevia plants daily
with small
amount of water. Any kind of watering system can be used. However,the
most recommended, but not the most used, is the leaking system wich
offers the following advantages:
- The water is distributed efficiently.
- Low use of energy.
- It is automatic.
- There is a possibility to transplant in any kind of land.
3) Fungi and
plagues: There were reported attacks in a few ocations.
- Fungus: The damage is almost always minimum, therefore, it is not
necessary the use ofchemical agents. In exceptional cases, when the
damage is significant, benomil metil-tiofenate are used.
- Plagues: there has been no report about significant plague attack in
the world. The use of chemical agents has not been recommended in any
case until the year 2009.
STEVIA LEAVES
MANUAL
1) Collecting
Stevia
leaves.
- Initiate the collection when 5% of the stevia flowers are open. By
this time, the leaves have their highest concentration of stevioside.
- Cut the plants above the land to preserve the roots.
- Preserve the 5% of plants to produce seeds increase plantation.
- It is required 1 worker per 1000 m2 of land to collect the
stevia leaves.
- Water the land daily the first 2 weeks the collection. Thereafter, do
it twice a week.
- Initiate the second collection 70-90 days after the first one.
- 4000 kg/Hectare/year will be collected. The plantation will be
preserved for 5-6 years without a need of renovation.
2)Drying the
stevia leaves.
- It is needed 100 m2of drying surface per hectare per week
of collection. Avoid this on raining days.
- Use synthetic fabrics to cover the area used for drying.
- The branches will be exposed to sunlight for 6 hours. The branches
must not be interporsed.
- The best moment to collect leaves is when they turn brittle with
10-12% of humidity.
- Mechanical dryers can be used. Use high pressure air at 70 C degrees.
- Collect the leaves with a rake with compressed extensions.
3) Storing the
dry
leaves:
- Store the dry leaves (dark green color) in bags (10 kg/bag) made of
synthetic fabric or jute.
- The bag must be stored in an environment with the following
characteristics: dry, dark, clean and protected from humidity. They can
be kept in this environment for 5-6 for commercial purposes.
- The light green leaves are despised in the market. They are
considered as sick leaves because they where stored in bad conditions.
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