Good Old Grapefruit

Every time I eat a grapefruit I wonder why it is named after a grape of all things?

First of all, it is said that grapefruit got its name because grapefruit grow in clusters on the tree, like grapes on a vine. But I don’t know if ‘grape’ is the first thing I think of when I see a heavily laden grapefruit tree – you’d think it would have been named after the unique, quite bitter flavour rather than a tenuous similarity.

The grapefruit belongs to the citrus family and is a cross between the orange and the pomelo. The tree, which does best in subtropical areas, normally grows to somewhere in the region of 5 – 6m although in extreme cases it has been known to reach 15m in height. It is an attractive tree even without the fruit, with glossy, dark green leaves and fragrant white flowers that look like typical citrus but are a bit on the large side. These flowers appear predominantly in late winter or early spring, but the tree can actually flower at any time of the year.

The fruit takes a long time, from 8 – 12 months depending on the climate, and is usually ready to harvest in winter. Trees will usually begin to produce fruit in their second or third year, and when they are established they can become prolific producers with crops of up to 500kg a year. The fruit itself is large (100 – 150mm in diameter), and either yellow or orange when ripe. The flesh ranges from pale yellow to deeply ruby-red, depending on the variety, and has a tart, acidic flavour that can cause your face to pucker up, but once a taste for it is acquired it can become a firm favourite.

You can tell that a grapefruit is ready to be picked when it has turned its mature colour, be it pale yellow, yellow or orange. Don’t rush the picking though, because they do get sweeter and bigger if they remain on the tree for longer. When planting a grapefruit tree, spend time on digging a really good hole (this is the rule for planting any tree) of at least 80cm deep and wide. Add a handful of bonemeal or superphosphate to the hole for root stimulation, as well as a decent helping of an organic slow-release fertiliser like Atlantic Bio Ocean, then backfill with the removed soil. Water well, and water the plant regularly every 2 weeks until it is established.

Because it is such a prolific producer of fruit, you will need to feed your grapefruit tree every 4 – 6 weeks with a fertiliser for the production of fruit, like Atlantic Flower and Fruit. As with many citrus varieties, it is possible to plant grapefruit trees in pots but if you do try to find a dwarf variety so that you don’t spend as much time pruning. If you can’t find a dwarf variety (it is difficult), stick to one of the more popular normal varieties, which should also be your choice if you’re planting it in the ground, such as ‘Star Ruby’, which has sweetish pink to red flesh. If you’d prefer a more traditional, yellow fleshed grapefruit, look for ‘Marsh’. This has large fruit with a pale yellowy-green skin and pale flesh.


Grapefruit trees are affected by the usual citrus suspects:

Citrus psylla – This is the pest that causes those bumpy leaves. A healthy tree can cope with this and you shouldn’t need to treat it. If the psylla is detected early and is still active then oleum can be used to get rid of it.

Citrus thrip – These tiny insects feed on sap and cause sabby silvery-grey scars on the skin. The solution is early detection and treatment with Margaret Roberts Organic Insecticide.

Leaf miner – Treat the tree as soon as you see the tell-tale signs of leaf miners (tunnels winding through leaves). EcoBuz Pest Pro is the answer.

Aphids – Treat with a pesticide such as Margaret Roberts Organic Insecticide to get rid of these pests, which can transmit serious diseases to your trees.

Citrus swallowtail – The larvae of this beautiful butterfly can be a problem, but live and let live. They won’t kill a healthy tree.

Sooty mould – This mould is only a problem when there are sap-sucking insects, as it feeds on the honeydew they produce. Take care of the insects with a pesticide and the mould will disappear too.

Top Tip

Celine (from the Grow to Eat office) says: “When you eat a grapefruit, remove every bit of the white pith – this is what makes it bitter! I promise –you will find this a revelation!” Unfortunately the pith is home to many of the nutrients and antioxidants, but you can’t have your pith and eat it too.

Five Facts

Grapefruit is:

  1. very hydrating, consisting of 90% water
  2. full of powerful antioxidants like vitamins A and C as well as beta-carotene and lycopene, which help to reduce damage caused by free radicals in your body
  3. good for weight loss. It contains very few calories and is high in fibre, so can make you feel full
  4. can lower bad cholesterol, reducing the risk of heart disease and strokes
  5. finally, the more coloured the grapefruit the better – red and pink ones have more antioxidants and are better for your immune system.

Grapefruit added to a fresh salad with prawns, avocado, cucumber and herbs brings the dish together with a touch of citrus. Grapefruit also makes a refreshing drink at any time of the day. Squeeze one or two grapefruits and pour into a glass with a mint leaf for flavouring.

The Gardener