Citrus paradisi 'Ray Ruby' – Ray Ruby Grapefruit

Site: Choose a warm, free draining position in full sun with shelter from cold wind and room for a broad canopy.

Soil preparation: Enrich a wide area with quality compost and aged manure, as grapefruit roots range well beyond the planting hole.

Hole: Dig twice as wide as the root ball and the same depth.

Planting: Set level with the surrounding soil and keep the graft union well clear of the surface, backfill, firm in, then water deeply.

Feature tree: 4 metres apart to allow the broad canopy to develop fully.

Home orchard: 3.5 to 4 metres between grapefruit trees so air moves through and each canopy carries a full crop.

Pot or container: A 60 centimetre or wider pot suits a single tree on a paved terrace.

Watering: Water deeply twice weekly through the first 12 months, then weekly in dry weather. Even moisture through fruit fill prevents split skins and fruit drop.

Mulching: Apply a 5 to 7 centimetre layer of organic mulch across the root zone, keeping it 5 centimetres clear of the trunk.

Pruning: Prune after harvest to hold the tree at picking height and open the centre. Remove any shoots arising below the graft union.

Fertilising: Apply a complete citrus fertiliser in early spring and again in late summer, with trace elements if leaves show yellowing between the veins.

Pest and disease: Watch for citrus leaf miner on new flushes, scale, aphids and bronze orange bug. Collect and remove fallen fruit to reduce fruit fly pressure.

Citrus paradisi performs best in deep, fertile, free draining loam or sandy loam at a slightly acidic to neutral pH. Adaptable to a range of soils when drainage is improved with organic matter.

Sandy soil: Free draining and suitable. Mulch heavily and feed more often, as nutrients leach quickly.

Clay soil: Improve drainage with gypsum and coarse compost, or plant on a raised mound.

Loam: The preferred soil for the deep root system a long hanging crop needs.

pH: Slightly acidic to neutral preferred. Correct alkaline soils to avoid iron and zinc deficiency.

Q: What is a Ray Ruby grapefruit?
A: Citrus paradisi 'Ray Ruby' is a red fleshed grapefruit selection grown for flesh that is noticeably deeper red than Marsh and stays that way as the fruit matures. The skin carries a pink blush over yellow. Flavour is sweeter and less bitter than white grapefruit, which is why it has largely replaced older red types.

Q: How is Ray Ruby different from Marsh grapefruit?
A: Marsh is a white grapefruit with pale yellow flesh and a sharper, more bitter edge. Ray Ruby has red flesh that colours up strongly and holds through the season, and the eating flavour is rounder and sweeter. Tree size and growing needs are much the same, so the choice comes down to fruit colour and taste.

Q: How big does Ray Ruby grow?
A: Expect 3 to 5 metres tall and 2 to 4 metres wide as a garden tree, with a broad rounded canopy. Growth is moderate at around 30 to 50 centimetres a year. Pruning after harvest holds it at picking height, and grapefruit takes a hard reduction better than most citrus if it outgrows its space.

Q: When does Ray Ruby grapefruit ripen?
A: Fruit ripens from winter into spring, roughly June through October depending on how warm the district is. Grapefruit improves on the tree, so leave it hanging and pick as needed rather than harvesting all at once. Fruit taken early is acidic. The longer it hangs, the sweeter and deeper coloured it gets.

Q: Do I need two trees to get fruit?
A: No. Ray Ruby is self fertile, so a single tree sets a full crop on its own. Bees still improve set, so avoid spraying insecticide while the tree is in flower. What limits cropping in practice is shade, cold at flowering and irregular watering rather than any lack of a pollinating partner.

Q: Where does grapefruit grow best in Australia?
A: Grapefruit wants heat and length of season, so it is at its best in subtropical Queensland, northern New South Wales, the Sydney basin, the Riverland and warm inland districts. It will crop in Melbourne and Adelaide in a sheltered north facing spot, though fruit takes longer to sweeten and stays more acidic.

Q: How do I care for a Ray Ruby grapefruit tree?
A: Feed with a complete citrus fertiliser in early spring and again in late summer, and water deeply and evenly while fruit is sizing, as erratic watering splits skins and drops fruit. Mulch broadly but keep it off the trunk. Remove any shoots below the graft. Watch for citrus leaf miner and scale.