Oak Valley

Production gets underway

“We knew the rootstock was excessively vigorous, so we decided on double leaders to break the vigour,” says Van Buuren. Double leaders are also a way to achieve high density without planting more trees. Krige reckons the double leaders did reduce vigour by 20–30%, as anticipated. “But G.778 is very, very strong,” he says. “That’s one thing I would do differently if I had to plant that site again – I would keep the double leaders but change the rootstock.” Wet conditions have exacerbated tree vigour in the lower-lying approximately 20% of the block. A similar – but more manageable – effect is visible in the adjacent block on M.9. “The best way to control growth is with crop load,” says Krige. “But the Grannies carried 13 tonnes per hectare in second leaf, which isn’t what we wanted. We wanted 20–30 tonnes, which is probably why the vigour ran away a little.” He elaborates that they were caught off guard by insufficient flowers. Young trees usually flower too profusely, and a sparse bloom was even more unexpected given the precocity of G.778. But the orchard subsequently yielded 42 tonnes per hectare in the third leaf, and the flowers are there for 60 tonnes per hectare in the fourth leaf. “I think the final potential is 150 tonnes per hectare,” says Van Buuren. “I’ll stick my neck out and say there’s a good chance we can get there in sixth leaf.”

Past and future training

Van Buuren considers blind wood the biggest challenge with Granny Smith, especially in warmer areas like Elgin. This is why he has put extra effort into notching to stimulate breaks. Oak Valley also used toothpicks to improve the crotch angles and discourage strong upright growth. However, Van Buuren feels the trees would have benefitted from more bending early on. This season, the plan is to prune between bud break and full bloom. “We definitely don’t want to stimulate the tree in any way, so we’re not making any winter cuts,” says Van Buuren. “But we also want to prune before full bloom. Otherwise, it becomes too complicated. And we’ll only remove big, ugly, offensive branches.” “At the moment, those trees are like Michelangelo’s marble blocks,” jokes Krige. “The beautiful thing is in there, but we must first remove the unwanted material.” The trees have been girdled and treated once with prohexadione-calcium just before full bloom in the third leaf. Both interventions will be repeated this season, with a second application of prohexadione-calcium if necessary. Van Buuren anticipates that the Grannies will start settling down and spurring up once they carry a sizeable crop. “The pruning strategy going forward will be reasonably simple: thinning out complex spur units and renewing one or two branches yearly.”

Nets are a no-brainer

Oak Valley has already demonstrated the benefits of shade netting on Granny Smith with its Orchard of the Future, planted in 2012. The profitability of this cultivar hinges on producing perfectly green apples without a hint of sunburn. The Elgin-Grabouw-Vyeboom-Villiersdorp area is less prone than colder areas to the development of unwanted pink blush on Granny Smith before harvest. Retractable grey nets protect the G.778 Grannies. “I can’t farm Granny Smith without nets – nets are pretty much a no-brainer,” says Van Buuren. He retracts the nets to expose the trees after harvest. They are kept uncovered for as long as possible in the following season to ensure light exposure during bud initiation, which is essential for return bloom. The critical period should have passed by mid-December when the risk of sunburn starts increasing. “It’s also good to keep the trees uncovered for pollination,” adds Van Buuren. “The bees do work better, although I don’t think it’s a major effect.” He hasn’t observed poor pollination under fixed nets in the Orchard of the Future Grannies, attributing this to ample space between the nets and the treetops. Oak Valley also uses four hives per hectare for apples under nets instead of its usual two.

Figuring out cover crops

Participants in the 2022 Hortgro field-day saw medicks thriving on the ridges under the double-leader Grannies. Two years later, Van Buuren admits to some unanswered questions about this cover crop. “I’m all for promoting soil health,” he says, “but it’s a little bit difficult at this stage to say whether the medicks are helping.” The medicks grew well in the first two years after an autumn sowing. The idea was for them to become self-sustaining from the third year – self-sown medick seed requires a scarification period, so it tends to germinate after two years in the soil. Unfortunately, the performance of the self-sown seed has been disappointing, even though Van Buuren sees plenty of seed in the orchard. “There’s a massive seedbed, but it’s not germinating yet,” he says. “What’s happening is that all my winter weeds come through quickly and almost smother the medicks that are there.” When he sowed the medicks, he treated them with a commercial inoculant that stimulated rapid germination. These medicks had a head start that allowed them to suppress winter weeds – the first-mover advantage matters in the weed world. “I’m not giving up,” says Van Buuren. “I will try applying the inoculant onto the bankie to see if I can kick-start the medicks. If I can force them to grow, it will be amazing. The medicks suppress weeds, fix nitrogen, aerate my soils, create a natural mulch, and put carbon back into the soil over time.”

Onward and upward

Krige and Van Buuren consider the G.778 Granny Smith orchard a commercial success. “It didn’t entirely hit its production target, but it didn’t miss it by much,” says Krige. “And I don’t think I’ve had a better-performing young solid Granny Smith block.” Nevertheless, if he could start again, he would plant the double-leader Grannies on G.890. Van Buuren agrees. “I would use something less vigorous than G.778 on my slightly weaker soils. We planted trial trees of G.890 last year, and we’re planting quite a lot of it this year and next year.” The problem with G.778 isn’t a lack of tonnes – it’s the effort required to control the trees. “I will get great production out of my two G.778 orchards. I do not doubt they will do well for me,” says Van Buuren.