Growing low chill stone fruit in subtropical climates

Low chill varieties or stone fruit varieties grown in sub tropical climates need some slightly different management to get the best out of the varieties.

Site selection 

Select a sunny, well drained position. For poor draining soils trees should be planted on mounds or hills.

 

Pre plant

3 months before planting, prepare soil  by adding mulch and pelletised poultry, or cow manure to the site. For pots a good premium potting mixed with about 10-20% of a good loam soil will give the mix extra body and assist with holding water and nutrients. The use of water crystals or a good soil wetter will assist in retention of moisture also.
Ensure the soil pH is between 6.0 and 6.5 for best results.

Planting 

Dig a hole twice the size of the nursery pot, do not tease the root system of potted plants. If planting in a large pot we suggest 50 cm diameter minimum size. Do not put fertiliser in the hole.  A closed handful of blood and bone fertiliser mixed into the bottom of the hole is fine.

If planting winter bare root trees look at the dirt mark on the base of the nursery tree and plant this at the soil or potting mix level. For potted trees plant the soil level in the nursery pot level with your soil or potting mix and add a sprinkle of soil to cover the roots in the nursery pot.

 

Fertilising young non bearing trees.

The focus for the first 12-18 months is on building a strong framework capable of bearing heavy crops. A good complete fertiliser or
composted manure is ideal. Give the tree a closed handful of fertiliser every 3 – 4 weeks
applied in a wide band from the drip line to within 30cm of the base of the tree. For pots use 1– 2 teaspoons spread evenly over the potting mix surface. Do not apply fertiliser against the base of the tree as this may cause tree death. Liquid fertilisers can also be used as well as the addition of a good trace element fertiliser twice a year is also important.

 

Fertilising bearing trees

From spring in year two from planting the focus now shifts back to fruit production. Avoid fertilising during flowering and early fruit set with fertilisers high in
Nitrogen (N).( up to 10% is ideal). A good balanced fertiliser with high potassium (K) above 12% is ideal. Give the tree a closed handful of fertiliser every 3 – 4 weeks applied in a wide band from the drip line to within 30cm of the base of the tree. For pots use 3 teaspoons and spread evenly over the potting mix surface. Do not apply fertiliser against the base of the tree as this may cause tree  death.

Liquid fertilisers can also be used as well as the addition of a good trace element fertiliser twice a year is also important.

 

Watering

Fruit trees peak water demand is from when the first full leaf forms after trees break dormancy. Not enough water at this time will cause poor fruit set and fruit
development. Continue to apply water in hot periods after harvest. Water needs will decrease from April on and trees may only need a third of what is required during the growing season.

Be aware potted trees may need water more often than in ground trees sometimes every day in hot dry periods.

Pests and disease control

It is extremely important with low chill subtropical stone fruit varieties that tree and leaf health is maintained during summer and autumn so as to achieve good even bud break in winter. If leaves are allowed to deteriorate in summer and autumn from poor nutrition and leaf fungal disease attack low chill varieties will break dormancy in April/May which is way too early and this will give a smaller crop and small tasteless fruit. Further information can be found on the PlantNet website pest and disease page.

Leaf removal 

If natural leaf fall is not completed by early June, strip leaves from trees. This is so the tree achieves strong, even bud break in mid winter, leading to larger tastier fruit.

Pruning 

This should be completed in June.

Fruit thinning 

For strong young trees up to 2 years old leave one fruit per lateral or twig. For trees 3 years and older leave 1 fruit on small laterals and 2-3 fruit on thicker laterals. Aim for 40-60 fruit per tree for strong healthy trees in year 3 and increase fruit numbers each year.