Port Growing environment

Question 1

Port: Factors affecting temperature

Answer 1

Douro Valley – Climate & Geography

• Location: NE Portugal
• Climate: Hot continental
  • Summer: Temps can exceed 40°C
  • Winter: Freezing not uncommon
• Western Douro Valley:
  • \~70 km from Atlantic
  • Sheltered by Marão Mountains → warmer and drier than coastal cities (Porto, Vila Nova de Gaia)
• Rainfall:
  • Coast: \~1200 mm/year
  • Mountains: \~1500 mm/year

Douro Subregions

Baixo Corgo

• Most westerly, coolest and wettest
• \~900 mm rainfall/year
• Cooler = grapes for inexpensive Ruby and Tawny Ports
• Produces lightest wines

Cima Corgo

• Further inland = warmer and drier
• \~700 mm rainfall/year
• Heartland of top producers
• Grapes used for age-indicated Tawny and Vintage Ports

Douro Superior

• Furthest east, hottest and driest
• Only 450 mm rainfall/year
• Avg temps \~3°C higher than Régua (Baixo Corgo)
• Drought is a frequent issue
• Sparsely planted but increasing due to flatter land allowing mechanisation

Topography & Other Notes

• Many tributaries from North and South → diverse aspects and elevations
• Elevation range: \~150 m to 900 m
• 1960s: River dams created string of narrow lakes
  • Slight temperature moderation
  • Ended traditional wine transport by boats down the Douro

Question 2

Port Factors affecting water availability and nutrient availability

Answer 2

Soils and Geology – Douro Valley

• Soil characteristics:
  • Stony, shallow, free-draining, low in nutrients (especially nitrogen) → naturally limits vine vigour
• Bedrock:
  • Schist:
    • Crumbles into layers easily
    • Split by ancient tectonic activity → vertical fissures
    • Allows rainwater to percolate and vine roots to penetrate deeply in search of water
    • Vital to vine survival → Port region boundaries align with schist zones
  • Granite (neighbouring):
    • Low permeability
    • Roots struggle to access water → difficult for vines to survive
• Irrigation:
  • Permitted in drought
  • Since 2019: no need for prior IVDP permission, but must inform of intent
• Rainfall:
  • Almost all occurs between November and April
• Dams:
  • Built in 1960s
  • Created narrow lakes along the river
  • Moderate climate slightly
• Rainfall:
  • Coast: \~1200 mm/year
  • Mountains: \~1500 mm/year

Douro Subregions

Baixo Corgo

• Most westerly, coolest and wettest
• \~900 mm rainfall/year
• Cooler = grapes for inexpensive Ruby and Tawny Ports
• Produces lightest wines

Cima Corgo

• Further inland = warmer and drier
• \~700 mm rainfall/year
• Heartland of top producers
• Grapes used for age-indicated Tawny and Vintage Ports

Douro Superior

• Furthest east, hottest and driest
• Only 450 mm rainfall/year
• Avg temps \~3°C higher than Régua (Baixo Corgo)
• Drought is a frequent issue
• Sparsely planted but increasing due to flatter land allowing mechanisation

Question 3

Port hazards

Answer 3

• spring frost at highest elevations (more common i west Baixo Corgo)
• cooler wetter weather goes through Marão mountains in early summer = disrupt flowering and fruit set
• Baixo Corgo can also have downy mildew and botrytis (due to higher rainfall than rest) = combat by canopy management and spraying fungicides)

drought

Question 4

Pests Port

Answer 4

Wild boar can eat fruit and damage vineyards

Question 5

Port vineyard establishment: key considerations

Answer 5

Key Vineyard Considerations in the Douro Valley

• Vine Density:
  • Efforts to increase planting density to improve yield and vineyard efficiency.
• Vineyard Layouts:
  • Designed to enable mechanisation, especially important on flatter areas and in Douro Superior.
  • Steep slopes (often >30%) limit layout options.
• Planting Material:
  • Careful selection of:
    • Varieties
    • Rootstocks (suited to soil, climate, water availability)
• Topography:
  • High variability over small areas.
  • Variety selection may change even over a single terrace.
• Appellation Area:
  • Total: 250,000 ha
  • Planted: \~41,000 ha
  • Registered for Port production (DO Porto): \~33,000 ha

Question 6

Socalcos

Answer 6

• protected by UNESCO = can’t be converted
• can be replanted for lower density for smaller tractor to fit = reduced labour costs
• traditional, narrow terraces, supported by dry rock walls
  planted along contour
• 1-2 rows
• density: as high as 6k/ha
• not suited for mechanisation + add. labour to maintain walls = not considered when planting new vineyards

Question 7

Patamares

Answer 7

Patamares (Terrace System – Introduced 1980s Boom)

• Origin:
  • Developed during 1980s after World Bank Scheme provided low-interest loans to Douro farmers.
• Structure:
  • Terraces supported by steep earth banks (not dry-stone walls).
  • Vines planted along contour lines.
  • Low planting density: \~3,000–3,500 vines/ha (earth banks occupy space).
  • Mechanisation possible:
    • Small tractors can access.
    • Diagonal tracks allow easier movement.
• Cost & Maintenance:
  • Cheaper to build and maintain than traditional socalcos (stone-walled terraces).
• Disadvantages:
  • Erosion risk on banks.
  • Weed growth can be problematic.
• Two Main Types:
  1. Large, Wide Patamares:
     • Two vine rows per terrace.
     • Efficient land use, but:
       • Uneven ripening (outer row gets more sunlight).
     • Built using large bulldozers.
  2. Narrow Patamares:
     • One vine row per terrace.
     • Avoids uneven ripening.
     • Modern version: carved with smaller bulldozers + laser tech.
     • Tilted toward hillside:
       • Improves water retention.
       • Reduces erosion.
     • Slight slope along length aids drainage in heavy rain.

Question 8

Vinha ao Alto (relatively limited use)

Answer 8

• planted vertically up/down slope
• high planting density (5k / ha)
• slopes less than 40% to allow mechanisation (steeper - patamares)
• better land use than patamares
  least expensive to plant and maintain
• disadvantages: water run-off, erosion

Question 9

Port overall considerations in planting materials

Answer 9

Vineyard Composition & Varietal Practices in the Douro

• Old Vineyards:
  • Often mixed plantings: 20–30+ varieties in a single plot.
  • Field blends: All varieties harvested together, regardless of ripeness.
  • Creates unique character vs. modern block plantings.
  • Old vines (“vinha velha”):
    • Some over 100 years old.
    • Crucial in premium/super-premium blends.
    • A few producers make rare, collectible wines exclusively from them.
• Modern Plantings:
  • Single-variety blocks.
  • Allows better control of ripening, pruning, and harvest timing.
• Rootstocks:
  • Chosen for drought resistance.
  • Common hybrids: 110R, 1103P (V. rupestris × berlandieri).
• Varieties:
  • Over 100 permitted.
  • Since 1980s, focus shifted to five key varieties.
  • Still, some producers use lesser-known varieties if they add value to blends.
• Blending:
  • Vast majority of Port made from blends.
  • Benefits:
    • Reduces vintage variation.
    • Balances different varietal characteristics.

Question 10

Port considerations in managing nutrients

Answer 10

Fertilizers, Weed Control & Sustainable Practices in Douro Vineyards

• Fertilizers
  • Used to improve nutrient-poor soils.
• Herbicides
  • Control weeds on patamares slopes.
  • Reduce competition for water and nutrients.
• Mowing
  • Small mowers used if space allows.
• Cover Crops
  • Planted in vinha ao alto (vertical vineyards).
  • Benefits:
    • Reduce soil erosion and water runoff.
    • Improve soil structure and nutrition.
    • Suppress weed growth.
• Organic & Sustainable Practices
  • Increasingly adopted by largest growers and producers.
  • Applied where possible and with certification.

Question 11

Port canopy management/harvest

Answer 11

Harvest and Vine Training in Douro

• Yield
  • Max yield for Port: 55 hL/ha.
  • Often around 30 hL/ha due to water limits, hazards, diseases.
• Harvest Timing
  • When flavours and tannins are ripe (or for field blends).
  • Sugar level usually sufficient; high sugar may reduce spirit volume needed.
  • Flavour and tannin ripeness can lower acid and increase pH.
• Vine Training Systems
  • Cordon trained, spur-pruned.
  • Head trained, cane-pruned.
  • Vertical Shoot Positioning (VSP) used to manage sun exposure, shade, ripening, and allow mechanisation where possible.
• Harvest Method
  • Mostly hand-harvested due to terrain unsuitability for machines.
  • Labour shortages from rural depopulation; Symington developing steep-slope machine harvester (since 2015).
• Harvest Timing & Process
  • Starts in Douro Superior (August), ends in Baixo Corgo (early October).
  • Spread over weeks due to microclimates, varieties, slow hand-picking.
• Grape Collection
  • Use 25-kg baskets to prevent grape squashing (improvement over historically larger containers).

Question 12

Managing hazards, managing pests and diseases

Answer 12

irrigation in special cases or with young vines
drought resistant rootstocks
Baixo Corgo: downy mildew/botrytis - canopy management + fungicides
Wild boar