How To Grow Cracking Cranberries

Cranberries are essential for Christmas lunch and so easy to grow

Cranberries are one of the staples of a Christmas lunch and the Thanksgiving dinner in the United States; homemade sauce is so much tastier than a jar from the supermarket. They are also great for making jam, juicing, drying and as a cocktail ingredient. They are easy to grow and require very little maintenance; even if you don’t have a garden they will grow quite happily in a hanging basket. They also give year round interest in the form of small pink flowers in summer, glossy red berries in early autumn and fiery red foliage in autumn and winter. In North America they are also known as ‘bearberries’ as bears gorge on them before going into hibernation.

Cranberry (Vaccinium oxycoccos) is a low growing evergreen shrub, up to 20cm (8”) tall, with creeping wiry stems, to 2m (7’). In the wild it grows in cool acidic bogs in the northern Hemisphere. They are a major commercial crop in the USA and Canada, and contrary to popular belief they are not grown in lakes, the beds are just flooded to enable easier harvesting in autumn; for the rest of the growing season they are kept moist. They are high in vitamin C and are also a good source of manganese, antioxidants, dietary fibre and micronutrients. They have always been known to ease urinary tract infections, however there is no scientific evidence to support this theory. In fact there is no evidence that they have any health benefits but there is on-going research into their effect on certain cancers, the immune system and cardiovascular problems. There can be negative effects associated with taking large amounts of juice, including inflammation of the stomach, kidney stone formation and excessive sugar intake, as a lot of sugar is incorporated into commercial juices to counteract the natural acidity. It also shouldn’t be taken by anyone who is on Warfarin.

Wild cranberries growing on a bog

Position

Sunny, poorly drained site.

Planting

Due to their creeping nature they are better planted in a dedicated bed so dig out a patch about 20cm (8”) deep. They are shallow rooted, 10 – 15cm (4 – 6”), and have very little in the way of fine roots; depending upon mycorrhizal fungi to supply nutrients. If you have sandy, free draining soil line the bed with thick black plastic and puncture with a fork. If you already have heavy clay soil you don’t need the plastic. Place plastic lawn edging or boards around the inside of the hole, this should prevent them spreading over the rest of the garden. Fill the bed with ericaceous compost, not coir, with a layer of horticultural sand over the top. Lightly dig the sand into the top of the compost. You can also incorporate a couple of handfuls of blood, fish and bone. Make sure the compost is wet but not sodden before planting. If you want to make the most of your space you can also grow blueberries, they both like the same conditions, with the cranberries acting as under-planting. Plant the cranberries about 45cm (18”) apart.

They can successfully be grown in a hanging basket, try 4 plants to a 45cm (18”) basket. Pierce the sides of the plastic about 5cm (2”) up the side, this creates a reservoir in the bottom of the basket and helps prevent them drying out. Use the same compost as for the garden bed.

Try and buy 3 year old plants as they don’t usually fruit until about 3 years old. If the plants are bare root they need to be planted over winter when they are dormant, provided soil conditions are favourable. If they are pot grown they can be planted at any time of the year.

Aftercare

It is crucial that they are kept damp at all times as they die fairly quickly if they dry out. Don’t let them become waterlogged as this impairs root formation. Make sure they are kept weed-free as they cannot stand the competition and won’t perform very well. Don’t feed for the first 2 years, if after this time they haven’t filled the bed give them a weak high nitrogen feed every month throughout the growing season. Once the bed has filled stop all feeding. Plants in pots and hanging baskets will need a little more fertiliser. Add a layer of sand every 2 – 3 years and lightly fork into the top of the compost. They need very little pruning, after about 10 years you can cut the runners back; don’t cut the uprights as these bear the fruit. If they have started to lose vigour you can cut the whole bed back to 5cm (2”), but you will lose a season’s crop. They could need some protection over winter if the weather is particularly harsh, so just cover with some horticultural fleece; some people advocate covering with a bark mulch but this is very labour intensive as it needs to be removed in the spring. 

Harvesting

Wait until the berries are a rich red colour. You should get about 0.5kg (1.1lb) of fruit for every 1.2 – 1.5 sq m (4 – 5 sq ft) of cranberries. If you have very little fruit it could be that they have had too much nitrogen based fertiliser. Bad weather when they are flowering or in bud, insects eating the buds or poor pollination due to bad weather resulting in the bees not flying or a lack of suitable pollinators (they are pollinated by bees) can also cause a poor crop. If you think that there is a lack of pollinators either grow plants which attract bees or run your hand over the whole crop a couple of times to dislodge the pollen. They are self -pollinating so do not need plants of a different variety. They will store for up to 2 months in the fridge in an airtight container or about 6 months in the freezer.

Cultivated cranberries

Problems

They are relatively problem free but do sometime come under attack from insects, in which case just spray with an organic insecticide suitable for fruit and vegetables. If you get some spotting of the leaves, usually in bad weather, take off and destroy the leaves, don’t put them onto the compost heap and spray with a food-safe fungicide.

Cranberry Sauce (Courtesy of BBC Good Food)

• 2 clementines
• 200g (7oz) cranberries
• 100g (3.5oz) light muscovado sugar
• 6tbsp port

1. Place juice of 1 clementine, cranberries, sugar and port in a pan and simmer for 5 minutes until cranberries soften and burst.
2. Add segments, without membrane, of the second clementine and cook for a further 2 minutes.
3. Store in the fridge or in the freezer for up to 2 months.

Cosmopolitan (Courtesy of BBC Good Food)

• 35ml (1½fl oz) vodka
• 15ml (½fl oz) orange liqueur
• 25ml (1fl oz) cranberry juice
• squeeze fresh lime juice
• thin twist orange peel to garnish

1. Shake all the ingredients.
2. Strain into coupe or martini glass.
3. Hold match under the orange peel, then decorate the glass.  

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