24 POLYTUNNEL GROWING 25 The sultry heat of the polytunnel is perfect for some exotic fruits Hot Under the Collar Give the plant a good mulch of compost each spring and feed during the summer – tomato IF YOU ARE looking for a passionate Christ by P. edulis, P. incarnata and P. vitifolia, so feed is as good as any. When challenge, try passion fruit. Easier to missionaries stick to these and you should be all right. the fruits fall off the plant they grow than to fruit, you have to be in South Seeds, which can be bought quite readily are ripe. You can cut the careful when eating them because America, from in the UK, need to be sown under heat in branches back once the plant some contain cyanide when unripe. where the plant late winter – January is a good time. threatens to hit the roof! Fortunately the poisonous fruit tastes originates. Some growers advise soaking the seeds awful and you do get spectacular flowers. It will grow on any soil as long as it but others don’t think it necessary. They Passiflora edulis is a fast-growing drains well and is fairly nutrient rich. It germinate in a month and grow quite Mango climbing shrub that will grow to 5m will not tolerate shade at all and in order quickly. By June they can be transplanted Another passionate plant, this time from (16ft) if allowed. It holds itself in place by to fruit it needs to be grown in the to their growing position in the tunnel. A India, the mango is great fun and easy to means of tendrils and flowers in this tunnel, although it will grow outside framework of wires against the end wall is grow. It requires nothing more than good country from July to August. The flowers quite well in the south of England. a good place, so long as it receives a old-fashioned TLC and not exposing it to are used to illustrate the Passion of The varieties with edible fruit include good amount of sunlight. temperatures less than 12oC (54oF). 26 POLYTUNNEL GROWING 27 The mango is the most popular fruit to keep them in the sunniest places, not patio where it can stay until around the in the world, with more being eaten necessarily for the heat it brings but second week in September. You are year on year. There are 1,000 varieties because they prefer full sun. looking to avoid wet, cold and driving of this fruit which has been cultivated Just because it’s winter doesn’t mean rain but you can cover it with by man for over 4,000 years. that citrus plants are going to ‘sleep’. In polythene because the end of For some reason the supply of mango fact, they actively grow during this September is often very warm. I have seed for growers in the UK has suddenly period, and most of them flower in the never had an orange outside in dried up with very few suppliers now winter too. An orange in flower on October. offering them for sale. No matter, you Christmas Day is a lovely sight! can get them from the supermarket. You will need a large terracotta pot because it’s porous and provides an Grapefruit GERMINATION amount of air to the roots. It needs to Grapefruit first appeared in the West Buy your mango from the supermarket be a minimum of 60cm (2ft) tall for a Indies – thanks to another mutation – and cut out the seed. Enjoy the flesh! small citrus tree and you can pot on in 1750, and were transported as buds Clean the seed and rough it up with a from here as it grows. Clearly there will all around the world. They were partic- piece of sandpaper. Place this in moist come a time when it isn’t possible to ularly prized by rich English compost at around 15oC (59oF). Keep it move the plant around because it is too RE-POTTING landowners who grew them in hot moist but not wet. Within six weeks the large. At this point treat it as a house AND PRUNING houses, even though they can be seed will have produced a shoot – plant and prune accordingly. This is best done in the spring. Trim dragged outside in the summer. The sometimes more than one in which case Fill the pot with a soil-based compost your plant just above a fat, lush-looking plants are larger than oranges and bear just cut out the weakest. (John Innes No 2), incorporating some bud, so the tree takes on a good, larger fruits. Otherwise they can be Transplant the seedling after three sand (say up to 15%) into the mix. All roundish shape and remains at the treated in exactly the same way. months of growth to a slightly larger pot citrus plants generally need the same appropriate height for your room and and keep moist and fed with tomato regime when it comes to watering and patio. food over the summer. Water every two feeding. They don’t like to stand in wet Re-pot yearly into the next size up. Kumquats weeks with rainwater – which they conditions but do enjoy moisture. Take Take the opportunity to add some slow- The fruits of this fast-growing tree can prefer. Only water in the winter to stop care not to over-water, simply make sure release fertiliser and fresh, well- be eaten whole. They are also supposed it drying out. After a year pinch out the the soil is slightly moist and that the draining compost. Gently remove some to be good pickled in brandy. They grow growing tip, which will make the plant pots are free draining. of the soil and ensure there is plenty of to be quite large and so are kept in a more bushy. You can repeat this on the Use a good-quality general fertiliser crockery in the bottom of the new pot single position. other branches to create a plant that is at least once a month – once a for drainage. Add new compost/sand happy being small. Mango trees in the fortnight in spring. Some people use mixture and firm in well. Give a good tropics grow to 10m (32ft). winter feed and a separate summer feed watering and keep the plant out of Clementines By the following June there should but as long as you use a good-quality, draughts/wind for a few days. These plants ripen around Christmas, be flowers and in the late summer fruits all-round fertiliser, this expense isn’t most being ready after November. should be ripening. Remove the fruit as necessary in my view. Feed less in the PESTS AND PROBLEMS They can be kept quite small, even late as you can at the end of summer. winter, just once every five to six weeks. All citrus suffer from the same group though they are vigorous plants. of pests: aphids, red spider mite and Annual trimming keeps them in check, PROPAGATION scale insects. A weekly wash with soft but you can grow them up a wall or as Citrus Most citrus plants will grow readily from soap will keep most of these in check. a large bush. The polytunnel is perfect for fresh seed but will take around a decade The plants drop their leaves regularly mimicking the environment needed to to flower and fruit, sometimes two. Plants in the winter, but should not lose grow citrus fruits. can be grown by taking hardwood more than a third. Any evidence of Limes Members of the citrus family – cuttings in the autumn. Around half will yellowing leaves could be due to over- Limes tend to be easy to grow and can oranges, lemons, limes, grapefruits and ‘take’ and after a couple of years the trees watering, lack of nutrients, low be restricted to a reasonably small tree so on – are prized for their flavoursome might produce fruit. All citrus plants temperatures or insufficient sunlight. about 1.7m (5ft 6in) high. There are a fruits and vitamin C content. In fact, bought from garden centres and nurseries Keep plants well ventilated but out of number of varieties and each grows though, they contain no more vitamin are grafted on to specialised rootstocks. strong draughts to avoid botrytis and well in the UK – some turning yellow C than most other plants, but this The vigour this ensures means that they other fungal infections. Above all, when ripening. A limequat is a cross notion has stuck around since will grow to their full height very quickly. water well but don’t allow them to between a lime and a kumquat. You Georgian times when they were used by Ask around and try to get the most stand in water. can eat the whole fruit, which tastes sailors to ward off scurvy. dwarfing rootstocks you can. much like a lime. E When you think of citrus fruit, oranges and lemons immediately spring Oranges to mind. But it’s possible to grow clemen- Every navel orange is a descendant of a tines, mandarins, satsumas, grapefruits, single mutant tree found in the early kumquats and limes as well. You can even 19th century in Brazil. It was budded grow bergamot – so you can make your and the small plants sent around the own version of Earl Grey tea. world. They’re very heavy fruit and, consequently, the trees need to be large CONDITIONS FOR GROWTH to take their weight. The fruits are Make sure you provide a frost-free seedless and have a small ‘baby’ fruit environment in the winter months.