Figuring out the fig!
The fig family is a complicated one when it comes to fertilisation, choice of variety, cropping and pruning, but very easy to grow in most soil conditions and in our climate.
Different types of fig
There are 4 types of fig:
- Adriatic or common figs which are a variety that do not need pollinating
- Smyrna which is not a variety but a group which does need pollinating and produces only one crop per year – it is considered the best fig
- San Pedro varieties which needs pollinating for their second crop but not their first
- Caprifig or wild fig which produces inedible fruit but contains both male and female flowers within its fruit and these are the source of pollen for the Smyrna group and the second San Pedro crop
The fig wasp
When you cut a fig open, what you are seeing are rows and rows of tiny flowers, all female except for the caprifig which has male and female. The question is, given that the fig is closed, how does pollination occur as the normal pollinators such as bees cannot access these flowers. The answer is the fig wasp (Blastophaga psenes) which is a tiny wasp that completes its whole life cycle within the caprifig and then exits through the tiny pores of the skin, covered in pollen. It then finds its way to the Smyrna and San Pedro’s then enters and pollinates them from the pollen attached to its body. This process is called ‘caprification’.
When do fig trees crop?
Fig trees can produce 3 crops a year:
- The first crop is called the breba crop and valued for its early fruit. It grows on the tips of last year’s wood (so don’t prune off all of this wood)
- The second crop is the main crop and grows at the base of the new growth produced earlier in the spring
- The third crop appears on some trees in autumn if they have been very well looked after
Choosing a site for a fig tree
Figs grow well in full sun but will grow in partial shade. Well drained, fertile, loamy soil suits them best but if your soil is clayey then dig a large hole and fill it with organic material such as compost and well rotted manure. They prefer a pH of 6-6.5.
Planting fig trees
Plant trees in winter and prune back immediately so that the energy goes into the roots and not into developing branches. Generally, prune your tree at planting by one third to a half, and prune to a vase shape with 3-4 main limbs.
Fertilising fig trees
This is contentious. Some people such as expert Louis Glowinski recommend ‘neglect’ except when shoots fail to grow more than 15cm in length or when leaves drop prematurely, while others recommend at least 500 grams of phosphate and potassium based fertiliser for every year of growth. Nitrogen fertiliser is not recommended as leaves will develop in place of fruit. If fertilising, do this in late autumn, winter and early spring.
Figs are shallow rooted and therefore require adequate watering up to the time fruit begin to ripen. At this time, cease watering to prevent fruit splitting and the development of fungal rot on the roots. Begin watering again after harvest.
Prevention of dry flesh in the fruit
There are 3 causes:
- Inadequate watering during long, hot spells or drought
- Lack of nutrients
- Caprifig fruit. If you have a caprifig, the fruit will always be tough, dry and inedible. You can either replace it, or plant a San Pedro or Smyrna nearby, which it will pollinate
Pruning fig trees
The type of fig you have and how many crops it produces per year determines your pruning regime. If your fig produces only one crop then you can prune it back hard each year. Also do this with old trees that are under-producing (and give them some fertiliser and a good watering). If you have a tree that crops two or even three times, then do not prune away all last season’s wood as the breba crop will produce on this. Pinch out the growing tips in spring however as this will allow the tree to put all of its energy into fruit production. The second crop will produce on the base of the new growth.
Figs do not continue to ripen once picked. Know what colour ripe fruit will be for your variety – green, brown or purple. To test for readiness, look for wilting stalks and drooping fruit, or give a gentle squeeze, testing for softness. Softness is not always a sign of readiness but firmness is definitely a sign to leave them longer on the tree.
Queensland Fruit Fly (QFF) and other pests
Figs are very attractive to QFF so must be netted (this also prevents bird attack and sometimes rats and possums too). You can spray with kaolin clay which will wash off but as the skin is edible, most people prefer netting. Fungal disease can attack the roots as previously mentioned and this is spread by the dried fruit beetle (Carpophilus) after it has feasted on over-ripe figs.
Propagation of fig trees
Propagation is by cuttings of about 20cm with three or four buds and some wood at the base of the cutting. Dip in hormone rooting mixture and strike in sharp sand or a mix of vermiculite and perlite. The process can take up to one year.
Varieties of figs
Check with your nursery for varieties. Black Genoa, White Genoa and Brown Turkey are the most loved ones.
Glowinski, Louis The Complete Book of Fruit Growing in Australia, Lothian,1991 reprinted 2005
Written by Robin Gale-Baker