Fertiliser Recommendations for Horticultural Crops
Passionfruit (Purple Granadilla)

Passionfruit (Passiflora edulis) tolerate a wide range of soil types provided they are free draining. Such conditions are essential to minimise the risk of root canker which is a complex disease resulting from a combination of Phytophthera, Fusarium, and Verticillium. The root system is extensive but shallow, and as such is easily damaged and may also be subjected to intense competition from weeds. In New Zealand fruit yields average from 10 to 17 tonnes/ha, but values of up to 45 tonnes/ha have been recorded.

PLANT ANALYSIS
Leaf samples for analysis should be taken in September prior to fertilisers being applied. The youngest fully mature leaf on well developed, actively growing laterals should be selected, with each sample consisting of at least 20 leaves taken from vines randomly selected throughout the orchard.

Standard leaf concentrations given in Table 1 are based on Australian figures. Copper leaf concentrations may be much higher in New Zealand, often around 250 ppm, due to the presence of residues from copper sprays used to control both fungal and bacterial diseases.

Table 1: Typical concentrations for foliar analysis of passionfruit.
Element Deficient Optimum Excess
Macronutrients (%)
Nitrogen
Phosphorus
Potassium
Calcium
Magnesium
Sodium
Chloride

Micronutrients (ppm)
Manganese
Iron
Zinc
Copper


< 4.75
< 0.25
< 2.0
< 0.5
< 0.25
< 0.1
< 0.6


< 50
< 100
< 45
< 5


4.75-5.25
0.25-0.35
2.0-2.5
0.5-1-5
0.25-0.35
0.1-0.2
0.6-1.6


50-200
100-200
45-80
5-20


> 5.25
> 0.35
> 2.5
> 1.5
> 0.35
> 0.2
> 1.6


> 200
> 200
> 80
> 20

SOIL TESTING
Target soil test values have not been determined for passionfruit grown in New Zealand. However, a soil pH of 5.5 to 6.5 is recommended for Australian conditions.

FERTILISER REQUIREMENTS
Under ideal conditions passionfruit is a vigorous and heavy bearing vine. To maintain high production large quantities of fertilisers are needed (Table 2).

Table 2: Maintenance fertiliser requirements for mature passionfruit vines, and estimated nutrient removal in a 15 tonne/ha crop.
Element Application Rate
kg/ha 		Crop Removal
kg/ha
Nitrogen
Phosphorus
Potassium
Sulphur 		150-200
30
200
30 		50
6
15
4

The fertiliser should be applied in two dressings, one half in September and the balance in late November, early December. In the first year the following quantities are recommended: 75-100 kg N; 30 kg P; 30 kg S and 100 kg K/ha. In all cases, fertiliser should be spread over the entire area between the trellises.

NUTRITIONAL DISORDERS
The nutritional disorders which are most likely to affect production are those associated with excess N, and deficiencies of Zn and Mn.

Research overseas has shown plants that are growing luxuriantly but yielding poorly may be receiving too much N. In such cases, a reduction in the amount of N applied while increasing that of P and K has resulted in increased production.

Zinc deficiency is relatively common in passionfruit. Symptoms include small leaves, distorted growing tips and yellow interveinal mottling of younger leaves. A foliar spray consisting of 100 g zinc oxide (ZnO) plus 300 g urea/100 l applied in spring when the new growth is a few weeks old, has been found to be effective.

Manganese deficiency is common in vines grown on calcareous and other high pH soils (pH 7.0) such as those found in the Poverty Bay and Hawke's Bay areas. Foliar sprays with manganese sulphate (500 g/100 l) may be used but a more effective measure is to treat the soil with an acidifying compound such as ammonium sulphate, finely ground elemental S, or aluminium sulphate.

FURTHER READING
Clark, C.J. and Smith, G.S. (1984). pH-induced manganese deficiency. Possible methods of correction. Southern Horticulture 18: 21-23.

Fletcher, W.A. (1973). Passionfruit Growing. Bulletin No. 135, New Zealand Ministry of Agriculture and Fisheries, Government Printer, Wellington. pp. 24.

Yerex, D. (1983). Passionfruit. Yet another chance. Southern Horticulture 12: 45-47.

Copyright © 1995 The Horticulture and Food Research Institute of New Zealand Ltd. All rights reserved. Reproduction in whole or in part in any form or medium without express written permission of The Horticulture and Food Research Institute of New Zealand Ltd. is prohibited.