Calcium and berry firmness
Most of the calcium a berry will ever hold goes in early, during cell division. Firmness and shelf life in the cold chain depend on it, so calcium is managed in spring — not rescued at véraison.
Table grapes · Tafeldruiwe
Independent agronomy for export table grapes.
Berry size, firmness and colour are decided in the vineyard long before the pack shed. We measure the soil, the leaves and the water, and advise independently of any supplier — so the programme is built for the cold chain, not for a product list.
What we measure, and when
A table grape season, measured.
Each sample is timed to the crop stage where it tells you the most. We work across the Hex River Valley, Berg River, Olifants River and elsewhere in the Western Cape.
| Season, July to June | Jul | Aug | Sep | Oct | Nov | Dec | Jan | Feb | Mar | Apr | May | Jun |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Budbreak to flowering | Aug | Sep | Oct | |||||||||
| Berry set & cell division | Oct | Nov | ||||||||||
| HarvestVaries widely by cultivar and region | Nov | Dec | Jan | Feb | Mar | Apr | ||||||
| Leaf & petiole sampleFull bloom | Sep | Oct | ||||||||||
| Leaf & petiole sampleVéraison | Nov | Dec | Jan | |||||||||
| Soil samplingPost-harvest, topsoil and subsoil | Mar | Apr | May | |||||||||
| Soil moisture monitoringProbes through the growing season | Aug | Sep | Oct | Nov | Dec | Jan | Feb | Mar | Apr |
Crop stageLeaf samplingSoil samplingMoisture monitoringTiming is approximate and shifts with region, cultivar and season.
What we look for
Where table grapes gain or lose quality.
The questions we put to every block's numbers — answered independently, with no product attached to the answer.
Nitrogen restraint
Excess nitrogen gives soft berries, poor colour on red cultivars and more botrytis. We keep nitrogen to what the canopy needs, measured rather than assumed.
Potassium for colour and sugar
Potassium supports sugar accumulation and colour, but it competes with calcium and magnesium. The balance between them is what we manage.
Water and berry size
Water stress during cell division limits berry size for good, and irregular irrigation near harvest is linked to splitting. Probes show what the root zone holds, so irrigation stays steady.
Boron at flowering
Boron shortage at bloom shows up later as poor set and uneven bunches. The bloom leaf sample is there to catch it in time.
Records for export
Spray and fertiliser records kept per block, with crop passports ready when an auditor or a buyer asks.
What you get back
Numbers you can act on, kept season after season.
We keep every result, so this season's numbers always sit beside last season's — and you get a written report after every visit.
- Soil maps per block, with calcium, potassium and magnesium balance
- Leaf and petiole results at bloom and véraison, against table-grape norms
- A fertiliser programme by nutrient, timed to berry development
- Probe readings with refill and full points through cell division and sizing
- Crop passports and spray records per block, ready for audits
Other crops
The same independent approach, crop by crop.
Contact
Talk to an independent agronomist about your table grapes.
Evert Bergh, agronomist. Based in Durbanville, serving farmers across the Hex River Valley, Berg River, Olifants River and elsewhere in the Western Cape, and nationally.