Potatoes

  POTATOES FOR THE GARDEN

 It is hard to think of any other vegetable that has had a major impact on the British way of life than the humble potato. It is eaten by most people daily as boiled, mashed, baked, as a salad or as chips.

It is a great source of food health and its cultivation gives us immense exercise.
It is a major farm crop in Scotland for both ware and seed potato production. It was even responsible for providing us with extra holidays during the tattie fortnight when school kids were granted time off from studies to help the farmers bring in the harvest. Although they are now all harvested by machines, the holiday period is still enjoyed by most people.

Howking tatties is still remembered by an older generation as a chance to escape from the housing estate to the fresh air of the country and earn a wee bit extra money. The autumn was usually cold but sunny, and it was never too wet. The work was very hard and that digger always seemed to appear just as you finished picking your bit and before you got a chance for a breather. The bonus was the beauty of the farming countryside and that bag of spuds that went unnoticed as it followed you home.

It was a way of life for many years, but nowadays it is all done by machinery and none disappears off site under the arms of a tired but happy picker.

History

Potatoes were grown in South America in Peru 8000 years ago, but it was not till the middle of the 16^th century that explorers discovered them and brought them back to Europe. At first they arrived in Spain then years later to Britain and Ireland though at this time there potential was not realized. The potato, Solanum tuberosum was still only of interest to botanists and herbalists.

Major changes to land use, industrialization and expansion of towns brought in a need for something easy to grow to feed the population. Potatoes were easy to grow, store, cook and transport. The Irish peasants took up their culture in the 17^th century followed by England in the 18^th century, appearing in fields, gardens and allotments. Scotland was slow to accept them at first as devout Scottish Presbyterians refused to eat them as they were not mentioned in the bible. Around the world they were thought off as unclean, linked to witches and the French thought they caused leprosy.

Soon populations in both Scotland and Ireland desperately depended on the potato for their sustenance, but then disaster struck when the climate changed to a wetter regime in 1845 and 1846. Potato blight thrived in the wet weather ruining the crops and leading to severe famine. The population had no choice other than to leave or face death by starvation.

Today plant breeders are still working on developing new strains of potatoes that have resistance to potato blight caused by the fungus, Phytophthora infestans. It can still seriously affect late and maincrop potatoes but earlies are often harvested before the disease can get a hold.

Potatoes are now a major food crop all over the world from Britain to USA, India and especially China.

Culture

To grow good crops of potatoes consistently every year it is necessary to be aware of the range of pests and diseases that can seriously affect yields and do everything possible to minimize the risk.

Start off by purchasing seed tubers only from Scottish or Irish sources where very strict hygiene conditions ensure the crop is clean and gets the highest certification. This information will be shown on labels on all bags purchased.

Farmers work under surveillance with plant inspectors so the crops are well rotated and always on land tested to be clean if the crop is for certified seed production. Gardeners and allotment holders should practice a four year rotation and make sure any ground keepers are removed immediately they appear. If you are tempted to retain seed potatoes from your own healthy crop, only do so for one year and only if the crop was very clean and free from blight and any other pest or disease. Never accept seed potatoes from a friend as the risks of potential infections are too great.

Potatoes are heavy feeders so grow best on land that has been well manured in autumn and left rough over winter.

It is a good practice to chit early varieties as it gives them a head start. Place the seed potatoes upright, (rose end upwards) in trays or egg boxes and leave in a light frost free position for a few weeks to get them to sprout. Some tubers may produce numerous sprouts. The smaller ones can be removed to leave two or three. This reduces the crop slightly but gives bigger potatoes.

Planting

Planting time is very much depending on weather, so in a mild period it could be the end of February, otherwise as soon as you feel there is some warmth in the ground in March.

Earlies are spaced about 12 inches apart along the rows which are 18 inches apart. For maincrops increase the spacing to 15 inches apart with rows 2 to 2.5 feet apart.

Take out a furrow six inches deep and run some well rotted compost along the bottom. Cover this with some soil and plant into this. Cover the rows but leave a slight ridge to mark the line.

Potato fertilizer high in phosphates and potassium, may be added during the covering of the tubers, but don’t allow direct contact with the tuber.

Growing on

Once the foliage emerges keep an eye on the weather and if frost threatens earth over to protect them. Continue to earth over as this kills weeds and creates a friable structure that potatoes love to grow in.

Hopefully earlies will escape blight, but watch out for blight on maincrops if wet weather predominates. You can protect the foliage with spays of Bordeaux mixture, but if rain keeps washing it off it may be better (if the crop is sufficiently advanced) to cut off and remove the foliage, but leave the crop a few more weeks to mature.

Lifting

Lifting can begin at the end of June with first earlies and continue till October for lates. Lift on a sunny day and leave the spuds to dry on the surface for an hour or so. Discard any tubers that show any greening as this contains poisons. Potatoes are best stored in the dark in hessian or paper bags in a frost free shed protected from mice. They can also be stored in the ground bedded on and covered with straw, then protected with a layer of soil.

New Spuds for Christmas

This is becoming a very popular activity to achieve fresh new potatoes for the Christmas table. Order some late stored tubers of an early variety ready for planting in June or July. Give them the best growing conditions, or in barrels, containers or growbags as they do not have a long season left to grow. Keep them watered and fed then as soon as autumn comes and the foliage dies off remove it and just leave them where they are. Do not give any more water and they will store perfectly where they are until Christmas, provided we don’t get any more early severe frosts.

Varieties

There are very many varieties to choose from in every category from first early to late and new ones appear every year. Personal likes also decide whether you like a dry, waxy or floury texture. Some have a strong flavour whereas others can be very bland. It is impossible for anyone to recommend the best range as they are all very different and personal. Read the catalogues, talk to other growers, then make your choice. Try out a new variety every year.

Research

Research at the Scottish Crops Research Institute and many other places is looking at increasing  vitamin C content and improving disease resistance, especially late blight, but also a host of others including blackleg, brown rot, ring rot and wart disease. The main pests under the microscope is the potato cyst nematode and free living nematodes. There is concern about disease in European potatoes which are being prohibited entry as seed crops but can be brought in as laboratory grown micro plants.

Glendoick Garden Centre will be holding a Potato Weekend on Saturday 5^th and Sunday 6^th February with potato grower and expert Alan Romans giving advice. They will be showing some of the Heritage varieties including Bonnie Dundee, Salad Blue and Shetland Black.

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Focus on Cuttings

  WINTER PROPAGATION

 This winter season may be severe and prolonged and all outdoor plants are well and truly dormant, but gardening is very seasonal and whilst it may not be possible to do much soil cultivations, there are many tasks that can be started now.

A lot of trees, shrubs, roses, fruit bushes and ground cover plants get pruned during the dormant season and it is these prunings that can make perfect cuttings when you wish to increase your stock of plants.

This is also the time to start sowing onions, and sweet peas if they were not autumn sown. If you have a good selection of geraniums and Impatiens which you wish to retain and have taken cuttings in autumn these will now be rooted and in need of potting up. I have kept the same geraniums going for many years as I have got really good colours for a brilliant summer display.

It is always very satisfying to produce your own healthy strong plants from seed and cuttings, rather than buy the more expensive mature plants. When training to be a gardener in the Parks Department in the early sixties the competitive spirit was always very strong and there was always someone who had bigger plants, more of them or had more flowers than the next. Propagation of all plants was a mark of your skills. Rose budding at the Camperdown  nursery sorted out the men from the boys as a high percentage take, speed of budding and clean grafting were closely monitored.

Although there is not a lot of fruit and vegetables grown in the parks, you were expected to acquire gardening skills in all topics, so training covered vegetables, fruit and greenhouse work as well as planting trees, shrubs, roses and bedding plants, grass cutting and landscaping.

It was at Duntrune Terrace demonstration gardens that I got my propagation skills honed under the watchful eye of a very skilled head gardener. My first home grown fruit bushes started off from cuttings grown from the gardens own stock of the best black currant varieties.

It was all part of the training exercise of course.

Hardwood Cuttings Fruit

Black currants, red and white currants and gooseberries are all propagated similarly as mature one year old shoots about pencil thickness. Cut them to about six to eight inches long with the lower cut under a node and the top cut above a bud. Leave all the buds on unless you wish to grow them as cordons or on a bare stem as with gooseberries. For these remove all the buds except the top two or three. Gooseberries are best on a leg to help picking as the weight of crop often pulls the branches down to the ground where the fruit gets splashed with soil.

Insert the cuttings about four inches apart in open ground in rows, leaving about one third of the cutting above ground. Leave them to grow on for a year before lifting them in the dormant season to go to their permanent spot.

If you are planting a new row of blackcurrants, you will only need to buy half the required number, as it is necessary to prune a new bush down to a few buds to get it established. Each new bush will normally have about four stems which after pruning will give you four good cuttings. Plant all four cuttings together in a square about four inches apart in the place of another bush.

After three years you will not see any difference in size of the bushes.

Hardwood Cuttings Ornamental Shrubs

There is a wide range of ornamental trees, shrubs and roses that can be propagated from cuttings very similar to black currants.

Poplar and willow trees must be the easiest and you should achieve 100% rooting almost every time. Take one year old shoots and cut to about ten inches long and insert into rows four inches apart leaving a third above ground.

Cornus, philadelphus, forsythia, buddleia and most roses can be propagated as above, but other ornamentals may need a wee bit more care.

Often the best time to take these hardwood cuttings is either two weeks before or after leaf fall or in March just before dormancy breaks.

Cuttings are taken about six to eight inches long, and some, e.g. pyracantha are better with a heel. Prepare a bed in a cold frame or other sunny sheltered spot mixing a lot of grit and some old compost into the soil to open it up, improve drainage but still retain moisture. Cuttings are lined out about four inches apart in rows six inches apart.

Commercially cuttings are often bundled up in batches of about twenty then plunged into an open frame full of sand or grit with soil warming cables underneath in late autumn. This gives cool tops so nothing breaks into growth, but the bottom heat encourages the base of the cutting to form a callus. The bundles are checked regularly, and then as soon as roots are seen to break out of the callus, they are lined out in another frame in ordinary propagation medium.

Allow all the rooted cuttings to grow on for a year before lifting, keeping them watered, and in summer protect them from strong sunshine.

For those with less sophistication it is possible to use deep boxes filled with a mixture of sand and old potting compost to take the cuttings in smaller bundles and sink it onto the top of a fresh compost heap where there is still some heat. Leave them there till mid March then line them out, when they will have callused over and some may show root initials.

The yellow flowered Jasmine is very easy to grow as long stems often fall onto the ground where they will root very readily. Hydrangea petiolaris also roots itself into soil and moist walls at every opportunity.

Stratification

Many shrubs, e.g. cotoneaster, pyracantha, rowans, and saskatoons grown for their ornamental or edible berries can be propagated from seeds extracted from these berries.

Once the berries are mature remove them and squeeze out the seeds. Wash any remaining pulp off the seeds as it contains germination inhibiting hormones, then either store them for a few weeks in a fridge, or sow them in trays and keep them outdoors. Keep them watered and protected from birds and mice. Over winter them outdoors, then in spring you should get a good germination of young plants. Grow them on for another year in soil or pot them up individually.

Greenhouse plants

Grape vines are very easy to root. I take pruned shoots about twelve inches long in January and over winter them in bundles in my compost heap. In March I cut all the plump healthy stems into one bud cuttings. Cut each one above a bud and leave two or three inches of stem below that bud. These can be inserted individually in pots, or spaced out in a cellular tray and kept in the greenhouse. By mid summer they will be rooted and ready to pot into a bigger pot. Once well rooted they can grow very strongly and as they are quite hardy grow them outdoors all summer and autumn.

Geraniums that were started off as cuttings last October are now rooted. They were inserted in wide shallow pots at five to a pot, but they soon filled the pot. I take out the tops to make them branch and let light into the middle otherwise at this time of year they would get very leggy.

They are now branching very nicely so potting them up into an individual pot and giving them more space will keep them short jointed.

I try to keep my greenhouse unheated as it is better for my overwintering grape vines, but it is too cold for geraniums. They can take a few degrees of frost, but not over a long period, so I keep mine on the windowsills in the house until March when I feel it will be ok to give them cold greenhouse conditions.

If a late frost threatens I do have a heater I can use for a short period.

Sweet peas can now be sown any time in January or February if they were not autumn sown. Last year they were autumn sown then overwintered in my cold greenhouse. That allowed me to plant them out early, but unfortunately this was followed by a cold wet spring and an even wetter summer so the display was miserable. This year I am not sowing too early. The seeds are soaked over night in a glass of water, then sown the following day at three seeds to a pot and germinated in my studio. Soon after they emerge they will be hardened off before going into the cold greenhouse. They should be ready for planting in early April on a good day.

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A Fresh Start

  NEW PLANS FOR 2011

 The beginning of January is the perfect time to look back over the previous year and analyze your gardening activities so that you can learn from your failures, build on your successes and plan new ventures. This applies to both my gardening activities as well as my painting projects.

Of course we are always at the mercy of our unpredictable weather and climate change brought on by global warming seems to be giving us a more extreme climate. New weather records get broken at a more frequent rate, whether it is the warmest summer, coldest day, the highest rainfall, or the heaviest snowfall.

Keeping in touch with weather forecasts is more important than ever before so we can plan seed sowing, planting, weed control and soil cultivations at the best times. It is even more important to make sure any spraying for pest, disease or weed control is done when a few days dry weather is forecast. There is nothing more infuriating than to have completed crop spraying then see it all washed off a few hours later. Last year was a very difficult year for spraying as the rain was never very far away.

The garden and allotment have never been subject to routine. There are so many new and improved plants to try, and ones that were previous favourites have gone out of favour if they have not been able to cope with a wetter climate. However I may be making a wrong assumption. Just because we have had four wet years and two severe winters in a row does not mean you can expect this to be a pattern. Prior to this we have had years of mild winters with hardly any snow, 2006 was a heatwave and my memory from childhood records seeing the first winter snows every year in November

However, it is great fun to experiment, so although I have tried many grape varieties outdoors in Dundee and discarded most of them, I will still continue with other varieties. Our climate may well get warmer and drier again and maybe I just have to find the right variety for Scottish conditions.

Paintings

With winter starting at the end of November, gardening has been put on hold till the snow melts and pruning and digging can continue. However the winter landscapes have been brilliant for painting ideas, so I have been going through the phase of planning art projects for the year ahead. The recession has had a big impact on art sales in the middle price bracket, but less so for smaller paintings. There is also a trend towards simpler images on unframed large stretched box canvases. So projects are being planned for a series of watercolour winter landscapes with minimalistic images, and some contemporary figure studies on large box canvases.

Now that could keep me occupied till next autumn unless of course we get a great summer and I will find it hard to choose between the spade, the hoe, the trowel or the paintbrush.

Flowers

The wet years have really sorted out the roses. Climber Golden Showers was always very reliable as was shrub rose L D Braithwaite, a gorgeous deep red, but they just could not withstand attacks of blackspot disease. Spraying with Dithane was not effective with the continual rain. They and many others have been dug out. The climber has been replaced with shrub rose Graham Thomas which is much stronger and will be trained as a climber.

I have a lot of very steep banks around the house where access to cultivate is a problem, despite a fair bit of terracing so these will be planted with drift of Fuchsia Mrs. Popple, Shasta daisies and some flag iris. This permanent planting will help to stabilize the bank.

Some of the bank was bedded out with spray chrysanthemums last year. I am hoping that these will survive the winter outdoors and grow again this year as a drift, of close planted stems that will not need any attention. Time will tell.

Vegetable Crops

Most vegetables cropped very well last year resulting in gluts of the usual courgettes, cabbages, lettuce, beans and sweet corn.

This year I must grow a wider range of crops and less of each as I am only feeding two people.

Although last year was a bit too wet for onions, I grew a Sweet Spanish Yellow variety from seed.

It was late, but produced an excellent crop that stores very well. I still have plenty firm onions left. I will grow that one again this year but must sow it a bit earlier.

Another success to be repeated this year was a super sweet type of sweet corn, and Swiss Chard Bright Lights has been very prolific, so I do not need so much, especially as we use a lot of Kale leaves in stir fries, and that is just as healthy.

With brassicas both cabbage Golden Acre for summer and Traviata, a savoy for winter will be grown again as well as Brussels Sprouts Wellington.

In the greenhouse it is hard to get a better tomato than Alicante for a large fruit full of flavor and my favourite cherry type is Sweet Million though the seed is expensive and not supplied in large quantities. Do not sneeze when sowing that one.

Fruit Crops

I grow just about every fruit available for eating fresh in season, in jams, compotes all year round, puddings, scones, pies, crumbles, smoothies and juices. It is very important to make sure selected varieties are the best for our local climate and soil. I have not always got it right, so there are many changes to be made this year.

I have several apple trees that provide eating apples from August till mid winter from those in store.

However,  I have too much Arbroath Pippin, (the Oslin) which is very early but does not keep so some branches will be changed to new varieties by grafting this spring.

Pears have the same problem as I have a large Comice tree that gets wiped out by scab in any wet year. Grafting will also be done to replace some of it. I will retain some Comice just in case we go back to warm dry summers again, as there is nothing to beat Comice in a good year.

Raspberry Glen Ample suffered a terminal root rot disease slowly killing the row over several years. The symptoms indicate it could be phytophthora. This fungus disease is spread in soil water so could be a problem if drainage is poor, or during prolonged periods of wet weather. I suspect the disease came in on infected new raspberry canes. There are several strains of phytophthora, some being quite specific to one plant host whereas others can attack a wider range of plants. I must have the latter as I also lost a white currant, and a gooseberry and some blaeberries also got infected. These were growing beside the raspberries, but lower down the slope. Different strains of this disease causes potato blight, sudden oak death and many other plant diseases.

I have replaced the raspberries with a new variety called Cascade Delight bred at Washington University and selected for tolerance to root rot. Hopefully the new canes planted last year will give me some crop this year. I will be sorry to lose my Glen Ample as it is an excellent variety.

I will also replace the white currant but will choose a different location.

I planted a new perpetual strawberry, Malling Opal last year, but it did not make a lot of growth so I will need to assess its performance this summer. It was replacing another perpetual, Flamenco which stopped producing runners, then died out. Perpetuals help to extend the strawberry season into the autumn without any protection.

Last year I tried another superfood fruit called the Chokeberry. Botanically, it is known as Aronia melanocarpa and the popular variety in Viking. The fruit can be a wee bit astringent if eaten fresh. Even the birds leave it alone till the end of summer, but it makes a terrific jam, compote, a deep red wine, and a very healthy smoothie. The berries are almost black and very high in vitamin C and antioxidants. The Aronia has one of the highest levels of anthocyanins of all known plants. The health benefits of aronias are being studied by food scientists. I have a batch of these sown in a tray and hope to have some plants by summer.

I now await delivery of a new cherry tree on the very dwarfing Gisela 5 rootstock, as well as a new grape vine called Solaris which I will try outdoors on a south facing fence, and hopefully I will see some white seedless grapes from a new vine, Perlette planted last year in the greenhouse.

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Winter Pruning of Fruit Trees

  WINTER PRUNING FRUIT TREES AND BUSHES

 The dormant season from November to March is the perfect time to tackle the winter pruning with   pruning saw, loppers and secateurs. Other garden tasks have been put on hold while we wait on better weather once all the snow melts, but pruning is mostly above ground level so deep snow and frost are no obstacle as long as you have warm clothing and the promise of some hot pumpkin or beetroot soup once the job is complete.

Pruning fruit trees and bushes has always been seen as a skill beyond most amateur gardeners and only acquired after good training and years of practice. Even in professional circles I have found great gardeners who never did break down the mystery of pruning. One expert propagator highly regarded for his skills in raising plants never got his gooseberry bushes to bear any fruit.

In reality the principles of pruning are similar for all fruit production although each type has its own needs.

I try to keep my pruning very simple and may not follow the book. I leave that to those undergoing training, who have to follow the Royal Horticultural Society precise methods so they understand the principles and get through their exams.

Then there is the commercial growers who wish to produce quality fruit with high yields, but with the minimum of labour input and aimed at producing trees that can all be picked from the ground.

My methods combine RHS principles applied with a simplified version of commercial practice.

My first aim is to produce a strong well shaped tree or bush, then prune lightly to encourage a balance of fruiting wood and replacement shoots. These must be well spaced to allow light into the tree to ripen up young wood so it can initiate fruit buds.

Pruning also removes weak growth, diseased shoots, crossing branches, branches broken with heavy crops or just too near the ground.

Apples and Pears

 

Pruning method varies depending on whether the trees are bush, cordon, espalier, stepover or fan trained. All of these can be spur pruned by summer and winter pruning. Cut back all side shoots to five or six leaves in mid summer, then again back to two buds in winter to encourage formation of fruiting spurs. In time reduce the size of these spurs otherwise you may get too many fruits at the expense of size.

Leading main shoots are reduced by a third in winter.

My apple and pears are grown as bushes so I do not spur prune them. I carry out replacement pruning of fruiting branches which have got too old and bent down with heavy cropping. This is done with loppers and saw, not secateurs, and I always look for a young shoot to replace the branch being removed.

If the tree becomes too vigorous, I do not feed in spring, but at the end of August. This feed is too late to encourage fresh growth so the tree uses it to build up fruit buds. Late pruning once spring growth has just started will also help to curb an over vigorous tree.

Plums

These are always pruned in summer to minimize the risk of Silver leaf disease. The spores of this disease are around from late autumn to late spring and could penetrate any cut surface.

Form a well balanced tree with five or six main branches in the early years. Plums tend to crop heavy and pull limbs down, so replacement pruning is perfect for them. There is usually plenty of young shoots to replace any limbs removed. Replacement pruning is carried out as required and not necessarily every year.

Peaches

These are usually fan trained against a warm south facing wall or fence, so pruning is carried out to keep the tree in this shape, and allow ample sunlight onto the ripening fruit. Fans have four main branches on each side. These are constantly being replaced by young shoots that are allowed to grow for one year producing new fruit buds that overwinter to make the following years crop. To allow sunlight into the centre of the tree remove all unfruitful shoots in late winter and during summer prune out weak growth, upright shoots and any showing signs of disease. Remove some foliage around the fruit in summer to help colour up the fruit.

Raspberries

Summer fruiting types fruit on canes produced the previous year. These are removed after cropping or in winter and the new shoots tied in. If the variety produces a lot of canes thin these out so that canes are spaced out at four inches apart tied along the top wire with a running knot.

Autumn fruiting types are cut down to ground level every winter as they fruit on new canes.

Blackberry (Bramble)

These are similar to summer fruiting rasps but the canes grow a lot bigger so have to be tied in to a wire framework where they are looped up and down to save space. Train the new canes up the centre and above the fruiting canes to keep them out of the way.

Tayberry and Loganberry is pruned the same way.

Blackcurrants

Immediately after planting cut the new bush down to a couple of buds on each shoot. These prunings can be used as hardwood cuttings to grow into more bushes. Blackcurrants fruit on one year old shoots and older wood. Prune after fruiting or in winter by cutting some older branches down to ground level or to a young shoot coming from near the base. Aim to replace all growth over about four or five years.

Red and White currants

These can be grown as a bush or a cordon as they fruit best on spurs. Allow the bush to form an open centre with about six main shoots. In early summer cut all side shoots to about six inches then in winter further reduce these to two buds. After a few years start to replace one or two main shoots every year with new young shoots.

Gooseberries

These fruit very easily as long as bullfinches don’t go pecking out the buds in spring. Pruning is mainly to make picking easier, so keep the centre open and also remove any low trailing shoots otherwise soil could splash the fruits. Remove any crossing shoots and overcrowded areas.

Saskatoons and Blueberries

Saskatoon  fruit bushes produce berries on all wood, so pruning is only carried out after several years to keep the plant down to an easy height for picking. Every year remove a branch down to ground level to encourage new sucker growth to keep the bushes young.

Blueberries also require little pruning for the first few years as they are quite slow growing. In later years cut some older branches down to younger shoots coming from the base or lower down the plant to rejuvenate the bush.

Grape vines

In Scotland these are either grown under glass or on a sheltered south facing warm wall. Under glass grow them on single upright rods spaced about eighteen inches apart and in winter cut every shoot back to one or two buds of the main rod. Shoots emerge from these spurs and form small fruit bunches. Allow these to grow then prune them to two leaves after the bunch. Then for the rest of the growing period cut all other growths to one leaf. In early autumn thin out more shoots and leaves to let sunshine ripen the fruit. Pruning wall trained vines outdoors is just the same, though grow them on a well spaced framework of main branches rather than rods.

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