Plant Doctor Archive

Passionfruit splitting

WE have an excellent crop of passion fruit in our green house but have noticed the green fruit starting to crack. What causes this? This is the second year and we have loads of flowers and fruit.

PASSIONFRUIT can be attacked by several diseases but it sounds as if your fruit cracking problem could simply be a lack of water at times. Check the stems and leaves carefully for signs of bacterial or fungal disease, such as spots or discoloured areas. If you can't find any and the cracks on the fruit look more like clearly defined splits than brown blotches, then lack of water is most likely the problem.

Passionfruit vines have quite shallow root systems so they are susceptible to water stress if the soil dries out even for a short period, which can happen in the greenhouse during hot weather.

At this time of year, when the vine is loaded with developing fruit, you need to maintain reasonably constant soil moisture. But, as they are also susceptible to root rot, take care to avoid waterlogging. You could apply a mulch of composted sawdust or bark to help stop the soil from drying out but keep it well away from the stem to avoid the risk of collar rot.

Passionfruit also need lots of fertiliser throughout the growing season to encourage strong growth and good fruit size so give them regular liquid feeds of a high nitrogen fertiliser such as Nitrosol or Foliar Nitrophoska or apply a dry feed to the soil and water it in.

Reproduced with permission from the former Weekend Gardener magazine. The views expressed here are not necessarily those of the RNZIH.