Commercial Cultivation of Gerbera is Naturally Ventilated Polyhouse

Gerbera is commonly known as ‘Transvaal Daisy’ or ‘ African Daisy’ is an important commercial flower grown throughout the world. It belongs to the family Asteraceae having single and double flowers. Plants are stemless and tender perennial herbs, leaves deeply lobed, sometimes leathery.

Gerbera is grown commercially for its attractive cut-flowers and is important both in the domestic and international markets. In India, it is frown in protected conditions mainly in poly houses. The flowers are exclusively used for all-purpose floral decoration.

Commercial cultivation of Gerbera for the production of cut-flowers in Polyhouse has been in practice for the last 10 to 15 years. However, it is confined mainly to Maharashtra and Karnataka. The technology was not popular in other parts of the country.

Agro-technology

For production of cut-flowers commercially round the year. Gerbera is grown in naturally ventilated Poluhouse. For establishment of poluhoyse following are necessary:

Site selection: The site selected for the establishment of Polyhouse should be level and away from high rise buildings and structures. The basic facilities like water, electricity and road connectivity should be available.

Soil structure: The soil should be highly porous and well-drained to allow better root growth having a pH between 5.5 to 6.5. The salinity level of soil should not be more than 1mS/cm.

Soil Sterilization: Before the plantation of Gerbera, it is absolutely necessary to disinfect the soil by following sterilization methods:

• By Sun heating: The soil is covered with plastic sheets for 6 to 8 weeks. Sun rays heat up the soil under cover killing most fungi.
• Chemical Sterilization: Formaldehyde: it is used at a strength of one part formalin (38 to 40 percent) to 50 parts water(approximately o.5 liter in 25 liters ) and the soil is drenched thoroughly( approximately 25 liters being required per m deg) to 25 cm depth. There is a waiting period of 20 to 40 days according to temperature before the soil can be used.
• Methyl bromide: It is used at the rate of 25 to 30 g/m deg as a soil drench.

Bed preparation: In general, gerberas are grown on raised beds for better drainage and crop management. The dimensions of the bed should be as follows:

• Bed height – 0.45 m
• Bed width – 0.60 m
• Pathways between beds – 0.30 m

Compostion of Bedding Material

Material	Clay soil	Silty Loam soil
Red soil	55 %	60 %
Sand	15 %	10 %
FYM	30 %	30 %
Rice husk	4 kg/m	22.5 kg/m sq

All material should be mixed thoroughly for optimum result. The composition of bed material should be higly porous, well drained and provide proper aeration to the root system.

Basal fertilizer Dose (After Bed preparation)

Area	Chemical	Quantity
10 m sq	Single super phophate	2.5 kg
10 m sq	Magnesium sulfate	0.5 kg
10 m sq	Biozyme granules	200 g
10 m sq	Humiguard granules	200 g

Details of Polyhouse

Polyhouse specificaiton

• Height – 5 to 6 .5 m
• Direction – North to South
• Gutter Direction – North to South
• Polythene thickness – 200 microns
• Vent opening – along the wind direction
• Distance between two adjoining playhouses hosuld be minimum 4 m.

Polyhouse operation: Sufficient ventilation space is required on top and sides. To protect the plants from the rains, without affecting the air circulation, side curtains should be kept open in slanting position. To control light intensity and solar radiation, a white shade net (50 %) is used.

approximately 35,000 to 40,000 lux light intensity is required for the plant. Side curtains should be kept open from 7 am to 6 pm in summer and rainy seasons, whereas in winter from 9 am to 5 pm, to facilitate maximum air circulation.

Polyhouse top shade net opening and closing: The polyhouse top shade should be kept open during cloudy days. On other days, it should be kept closed from 10 am to 4 pm. During cold nights, the shade net should be kept closed. In the summer season, the shade net should be kept closed from 9.30 am to 5 pm.

Some conditions for better yield:

• Wash top of plastic with clean water at monthly intervals.
• test water and soil samples for EC and pH periodically.
• The ideal temperature for Gerbera flower initiation is 20 to 23 deg C and for leaf unfolding is 25 to 27 deg C.
• The flowering of Gerbera is hampered below 12 deg C(bud initiation will stop)and above 35 deg C (production of flowers will be very low).
• The optimum humidity onside the polyhouse should be 70 to 80 percent, which will maintain the health of the plants.

Planting: While planting Gerbera plants, the crown of plants should be 1 to 2 cm above the soil level. As the root system establishes, the plants are pressed down. Therefore, the crown must be above the ground level at planting and also throughout the life cycle. Seedlings should be planted without disturbing the root ball (25% above the soil: 75 % below the soil).

Generally, two rows should be planted in one bed at 37.5 cm distance and 30 cm distance between the plants in one row. The soil surrounding the plant should be raked every fortnight for aeration. After plantation, the humidity is maintained at 80 to 90 % for 4 to 6 weeks to avoid desiccation of plants; avoid excessive watering.

Recommended varieties: Danaellen, Goliath, Rosalin, Salvadore, Silvester, Sunway, Zingaro. CSIT-IHBT has developed two varieties – ‘Him Glow’ and ‘Him Peace’.

Irrigation: Water quality should be as follows:pH6.5 to 7; EC <0.7 mScm; T.D.S < 450 ppm; Hardness < 200ppm. To lower the pH of water, Nitric acid or phophoric acid can be added to the tank.

Immediately after plantation, irrigate the plant with overhead irrigation for three weeks to enable uniform root development. Thereafter, gradually shift to drop irrigation. Generally, one drip per plant is required. The water requirement of the Gerbera plant is approximately 300 to 700 ml per plant per day depending upon the season. In hot summer, foggers can be used to maintain the humidity of the air. The foggers should not be operated for more than 30 seconds at any given point in time.

During summer season, apply water to the edges of the beds frequently by using shower to minimize the evaporation losses and to maintain micro climate. For this purpose provision for water outlets(2.5 cm diamter pipe) should be made inside the polyhouse. As a thumb rule, the soil should be moderately moist with no exessive watering.

Fertilization: After three weeks of plantation, apple N:P:K 1:1:1(eg: 19:19:19) @ 0.4 g/plant every alternate day with EC 1.5 mS/cm for first three months during the vegetative phase to have better foliage. Disbudding operation is to be carried out until 16 to 18 fully developed leaves are present on the plant. Thereafter, the generative stage fertigation caan be commenced.

The generative stage fertigation comprises of N:P:K 2:1:4 (eg: N:P:K 15:8:35) @0.4 g/plant every alternate day with EC 1.5 mS/cm to enhance the quantity and quality of flowers. Irrigate and fertilize frequently in small quantities for optimum results. Micronutrients(eg: Fertilon combi II, Micro sole B, Rexolin, Sequel, and Mahabrexil @ 40 g per 1000 liter of water) should be given weekly as per the deficiency symptoms. Add organic manures with EC less than 2 mS/cm at every 3 months interval to maintain proper C: N ratio).

Method of Fertigation: Fertigation should be given early in the morning at 6 am for better uptake by the plants. Take the recommended quantity of fertilizers and dissolve them insufficient quantity of water. After every fertigation, open flush valve to drain water from laterals and sub mains. Periodically clean the fertigation system to avoid any type of malfunctioning.

Harvesting of Flowers: The first set of flowers are produced 7 to 8 weeks after plantation when plants are having 14 to 16 leaves. The average yield is 240 flowers per m sq (6 plants per m sq). The flowers are harvested when 2 to 3 whorls of petals have entirely been developed.

Pluck the flowers in the morning or late in the evening when the temperature is low. Pluck the flower from the plant rather than cutting them. After harvesting, place the flowers immediately in water for four hours at 14 to 15 deg C. Generally, 250 to 300 flowers are packed in a box. A good gerbera flowers stalk length is 4.5 to 5.5 cm and the diameter of the flower is 10 to 12 cm. A Gerbera cut-flower has a minimum vase life of 8 to 10 days.

Pests and Diseases

Pests

1. Whitefly: It occurs when the climate is hot and dry. Feeds on the lower side of leaves, excrete large quantity of honeydew like substance which leads to the development of black sooty molds on the leaves.
2. Leaf Miner: White specks on leaves are caused by flies, white serpentine tunnels in leaves are caused by larvae, which stays in the soil.
3. Red Mites: They suck the sap from lower sides of the leaves causing the development of brown spots on the lower surface of leaves resulting in marginal drying of leaves. Webbing on the flower petals.
4. Thrips: Causes white specks or stripes on ray florets, flower heads may be deformed. Silvery, grayish spots on the leaves; Brown spots on leaf petioles/midvein.
5. Caterpillar: The caterpillars eat leaves voraciously making circular holes in the leaf lamina. It causes white spots on the petals in case of a flower attack.

Diseases

1. Crown Rot: Caused by Phytophthora cryptogea, it results in wilting disease of Gerbera and the crown of the plant becomes black.
2. Root Rot: Caused by Pythium, the initial dropping of younger leaves is followed by wilting of the plant. Root skin gets easily removed.
3. Alternaria Leaf Spot: Develops when moisture persists on the leaf surface for a longer duration. Black circular spots appear on leaves.
4. Powdery Mildew: White powdery growth is seen on the leaf lamina. In case of severe attack, the leaves start curling.

Pest control

SlNo	Pest	Suggested Pesticide	Concentration pet liter
1	Whitefly	Rogor(Dimethoate) Neemozal	2.0 ml 2.0 ml
2.	Leaf Miner	Acephate Cypermethrin	1.5 g 0.5 ml
3.	Thrips	Nuvan(Dichlorvos) + Nucrom(mMonocrotophos) Rogor(Dimethoate)	1.5 ml + 2.0 ml 2.0 ml
4.	Red Mites	Wettable Sulphur Kelthane(Dicofol)	1.5 g 1.5 ml
5.	Catterpillar	Lannate(Melhomyl) Thimet(Phorate)	1.5 g 2.0g per plant

Disease control

Sl.No	Disease	Suggested Control	Concentration per liter
1.	Root Rot	Aliette(Fosetyl Alluminium) (SP) Bavistin(Carbendazin) (D)	1.0 g 2.0 g
2.	Crown Rot	Aliette(Fosetyl Alluminium)(SP) Blitox (Copperoxychloride) (D)	1.0 g 1.5 g
3.	Alternaria Leaf Spot	Dithane M-45(Mancozeb) (SP)	1.5 g
4.	Podery Mildew	Wettable Sulphur(SP) Quintol or Rovral(Iprodion + Carbendazim) (SP)	1.5 g 0.5 g

Projected Economies ( in three years)

Area: 560 sqm (28 x 20 m)
Spacing : 0.30 x 0.30 m
Total plants : 3000 nos
Total cost: Rs. 8.0 lakh
( Rs. 6.0 lakh for Polyhouse and planting material + Rs. 2.0 lakh for maintenance)

Number of flowers: 3.0 lakh flowers (avg 40 flowers per plantpet year)

Sale value of flowers : Rs.15 lakh (Rs. 5 per flower)

Net profit : Rs. 7.0 lakh