Bakgatboord Series – African Delight at St Kilda Farm

Despite the intense heat in the 2018/2019 season, the plum farm St Kilda in Bonnievale still managed to produce a set of about 300 fruit, having had to drop only 100.

A set of 500 is considered too big and would require a considerable amount of fruit to be dropped, which is a very energy-intensive experience for a tree.

Not to mention that the fruit tend to bear the brunt, in terms of the resultant smaller sizes.

What worked well and why

The success of this block is mainly the result of a combination of three factors: good soil, a plum tree-filled environment and an early-blooming cultivar. While many plum growers struggle with poor soil, especially mountain soil, owner Gerrit van Deventer says they are lucky enough to have the ideal soil for African Delight at St Kilda Farm. Furthermore, the environment provide optimum soil, as well as an area with an abundance of cross-pollinators. “What really helps is the many plum trees in the environment,” says Van Deventer. “We did not have to plant cross-pollinators – they are already there.” The cultivar itself, half of which was grown on Marianna and the other half on GF667, is also key to the orchard’s success. Fruit sizes for both rootstocks were good, and although African Delight sometimes struggles with colour on GF667, the fact that it is an early blooming cultivar was central to its success in the previous season’s climate.

A Case of extreme temperatures

“In my 15 years of farming, I have never experienced anything like this,” says Van Deventer about the temperatures in 2018. “It was truly a case of extremes.”  The flowering season was off to a cold start. However, temperatures rose quickly with a single week at the end of the flowering season experiencing heat in the zone of 40°C. This is where African Delight was the perfect plum cultivar, blooming early in the season when temperatures were low. Late blooming cultivars tended to set quite poorly in the heatwave that followed.

Looking to the future

Despite a very challenging season, St Kilda Farm succeeded to deliver very good production. “I think the orchard is doing just fine and I am very pleased with its yield. The numbers are good.” Their successful season has taught Van Deventer the importance of a few basic things. He advises fellow plum farmers to plant enough cross-pollinators, if they are not abundant in the surround-ing area. Enough pollen for cross-pollination is crucial for ensuring an optimised fruit set. Then there are the rising temperatures. “Every year is getting hotter,” says Van Deventer. “We need cultivars that require less winter chill, rather than those that need very cold conditions.”