Grafting Trees and Tomatoes

This grafted tomato plant is doing very well after only 16 days. Pics: Chris Kafer

This week a few people have asked me why shoots are growing from the base of their ornamental trees.  They are a bit bemused because the leaves coming from the fresh shoots bear no resemblance to the top growth.  This growing of two types of trees on one stem happens because of a process called ‘grafting’.

Grafting

Grafting has been practiced for thousands of years. It was in use by the Chinese before 2000 BC. This is a horticultural technique whereby tissues from one plant are inserted into those of another so that the two sets of tissues join together.

In most cases, one plant is selected for its roots and this is called the stock or rootstock. The other plant is selected for its stems, leaves, flowers, or fruits and is called the scion or cion. This is the bit that has the desired fruit, leaves and flowers. There are a few different methods such as stem or bug grafting.

Fruit trees are a popular grafted tree and are god because:

• If they were grown on their own root system, many would be too vigorous.
• Cultivars will not usually come true from seed.
• A fruiting plant can be produced in a shorter period of time.
• A weak-growing cultivar can be invigorated and produce far more fruit.

Ornamental shrubs and trees are also grafted, especially when:

• It is difficult to propagate by other means, such as cuttings or cultivars do not come true from seed.
• It’s needed to strengthen plants that grow weakly on their own root systems.
• When we need to  produce a larger flowering plant in a shorter period of time.

Acer palmatum, Hamamelis, Wisteria, Thuja and Picea are examples of commonly grafted plants.

Most apple trees in modern orchards are grafted on to dwarf or semi-dwarf trees planted at high density. They provide more fruit per unit of land, higher quality fruit, and reduce the danger of accidents by harvest crews working on ladders. Care must be taken when planting dwarf or semi-dwarf trees. If such a tree is planted with the graft below the soil, then the scion portion can also grow roots and the tree will still grow to its standard size.  The roots of the stock plant will also grow stems, especially if they are damaged by mowing around the tree. Some cherry tree growth can appear metres away from the main trunk. 

Re-use

All of the main rootstock growth can be cut of and rooted again.  If you ever fancy doing a bit of grafting yourself, you will have the rootstock to play with. Probably better just to compost them though.

Protection

In areas where soil-borne pests or pathogens would prevent the successful planting of the desired cultivar, the use of pest and disease tolerant rootstocks allow the production from the cultivar that would be otherwise unsuccessful. 

Joining together

Tree branches and more often roots of the same species will sometimes naturally graft; this is called inosculation. When roots make physical contact with each other they often grow together. A group of trees can share water and mineral nutrients via root grafts, which may be advantageous to weaker trees, and may also form a larger rootmass as an adaptation to promote fire resistance and regeneration.

A problem with root grafts is that they allow transmission of certain pathogens, such as Dutch elm disease. Inosculation also sometimes occurs where two stems on the same tree, shrub or vine make contact with each other. This is common in plants such as strawberries and potato.

Grafting Tomatoes

Tomato Grafting has been utilized worldwide in Asia and Europe for greenhouse and high tunnel production and is gaining popularity in the rest of the world.  Typically, stock or rootstocks are selected for their ability to resist infection by certain soilborne pathogens or their ability to increase vigour and fruit yield. The scion of the grafted tomato represents the upper portion of the plant and is selected for its fruit quality characteristics. There are several methods for grafting tomatoes , most of them are pretty difficult and require really clean equipment and perfect growing conditions. 

    

The main reason for grafting is soil borne disease resistance.  Many desirable tomatoes are susceptible to pathogens like Fusarium, Verticillium and nematodes.  These can be devastating pathogens that lead to total loss. Many commercial hybrids have been bred to resist these pathogens.  Great for commercial growers but not so great if you want to grow heirloom varieties which typically lack any disease resistance, but some argue are the tastiest.  I have loads of self-set ones in the tunnel again this year (my favourite weed) so I am going to have a play. You never know it might be a new variety, although maybe not as strange as the pomato. These are a grafted potato rootstock onto a tomato top. Two crops in one.

Growing Luffas

I’ve decided on my new plant to grow this year. My new vegetable of choice is the luffa, or loofah as it’s also known.  They are a member of the cucumber family and as I have had a lot of success with those in the tunnel over the years I think loofas make an ideal choice. 

 

We are probably all familiar with the loofa plant without knowing it as the dried fruit is often used in the cosmetic industry. I first saw one when I was a child and the two foot length of stiff fibrous plant was in the bathroom being used as a back scrubber. At the time I thought this was very tropical looking and came to the wrong conclusion that it was from the sea and similar to sponge.

The luffa fruits are edible when young and are a popular vegetable in China and Japan and In Paraguay, panels made out of luffa are combined with other vegetable matter and recycled plastic, which  can be used to create furniture and construct houses. Loofa’s can also be used as a pan scrubber, a skin exfoliator, a metal cleaning pad, hydroponic plant growing, cool looking plant pots and as a painting tool.

The sap from the plant also seems to deter pests and the flowers will attract a lot of pollinators.  The powdered luffa fibers have been an ingredient in traditional Chinese herbal medicine. One Egyptian study found the seeds of luffa reduced blood glucose levels in animals, but I’d consult the experts if you were using the plant for this purpose.

Varieties and plant material

There are two species of luffa – Luffa acutangula, best for flavour, which looks like a fluted green barrage balloon about 28cm/10in long and L..cylindrica, which looks very similar to a courgette, except that the skin is smooth, shinier and fairly hard rather than slightly bristly. Both have similar leaves, deeply lobed and sprawl rather than climb, using tendrils. The flowers look similar to a courgette and can also be eaten; we deep fry our courgette ones in batter.)

Planting

Luffas need a long growing season so I’ll need to plant now (April to May). There is some evidence that soaking the seed for 24 hours in lukewarm water before sowing encourages germination.

Emergence rates are often low even with fresh seed, so I’ll plant twice as many as I need. I’ve been told they can get heavy so I’ll see how they do running along the ground, it this takes up too much space I can tie them to the frame of the polytunnel, if they are anything like cucumbers they won’t climb particularly well and might need a bit of help.

Easy Care

Established plants can grow to 7m/22ft but often reach less. Luffas aren’t very demanding in their soil requirements thankfully , and don’t need as rich a soil as other cucurbits, but once flowers appear weekly feeding with comfrey liquid should improve the fruiting. 

Male and female flowers are carried independently on the same plant, but in poor conditions only male flowers may develop.

A well-grown luffa plant can support about 6 or 7 fruits to maturity, although as with courgettes if you keep picking the plants will continue cropping throughout the season.

Healthy

Luffas are reasonably healthy but can suffer from the same problems as other cucurbits, especially powdery mildew if the weather conditions are suitable, especially during late summer with humid nights and dry soil. Watering the plants well and removing the worst affected leaves will help control the disease. Plants grown indoors can be prone to develop spider mite infestation in hot summers, so I’ll need to look out for the signs.

Harvesting and storage

It looks like luffas for eating are better when they are 30cm/12in long, as otherwise they become tough and bitter. Some seeds sold for growing here may taste bitter anyway, because they are for strains selected for sponge production. Peeling and sprinkling the cut flesh with salt may help remove some of the bitterness but if you find you have one of these you might as well grow yourself a back-scrubber rather than try eating the inedible.

It looks like the fun bit of growing them for scrubbers is to wait until the skin is hard and just turning colour if you want a pale coloured sponge, or allow the gourd to turn brown if you want a dark-coloured fibre. The skin is hard but brittle so throwing the fruit hard against a brick wall or concrete path is an easy and rewarding way to crack it. Then peeling off the split skin using a sharp knife and rinse the pulp under a running tap outside until the seeds and skeleton of fibre are revealed seems to be the popular way of revealing the fibres. 

If the remaining fruit is placed in a bucket of cold water to soak for a week the remaining flesh will begin to rot and can be removed completely, revealing the cleaned loofa. Combine this with a piece of soap and you have the perfect present for people.

Tobacco Growing in Ireland

 Growing Tobacco in Ireland. Pics courtesy of County Museum Dundalk

I like to have a go at growing new things every year.  There is one plant that so far I haven’t tried to nurture and that’s the tobacco plant (Nicotina tabacum), but I think this year I will have a go.

Like tea (Camellia Sinensis) and industrial hemp (Cannabis sativa), tobacco plants are actually ideally suited to some areas of the country and are only not grown much because of licencing and laws. This wasn’t always the case though. Up until the 1900’s hemp was the most common material for household and farm use as it has so many uses from clothes, mulch, animal bedding, milk, paper and ropes to a valuable nutritional seed food.  

Tobacco on the other hand was really only grown for smoking, but it does have a use in the garden. On a small scale, tobacco has been used as a natural organic pesticide for hundreds of years. It’s getting new scientific attention as a potential mass-produced alternative to traditional commercial pesticides that are increasingly getting unpopular. 

It might not be long until the country is covered with hemp, tobacco and tea fields as demand for natural products increase.

Process

The simple process to turn tobacco plants into a pesticide involves heating the leaves to about 900 degrees Fahrenheit in a vacuum, which produces an unrefined substance called bio-oil.

For centuries, gardeners have used home-made mixtures of tobacco and water as a natural pesticide to kill insect pests.  A “green” pesticide industry based on tobacco could provide additional income for farmers, and as well as a new eco-friendly pest-control agent. There doesn’t really need to be any need for killing in the garden if we embraces the eco system, but this is being created more for an industrial use on farm crops. 

Tobacco History in Ireland

The history of tobacco growing in Ireland is fascinating. Tobacco was once quite a popular crop in the more eastern counties of Ireland. The notion of widespread tobacco cultivation in the country was first proposed in ‘The improvement of Ireland’ (c. 1698) by the Jacobite Thomas Carte.

One estimate has it that a fifth of all tobacco consumed in the United Kingdom during the 1800’s originated in Ireland, and the success in growing tobacco on reclaimed bogland was almost certainly a factor in the commercial spread of the crop.

In the latter part of the eighteenth century, there was an upsurge in tenant farmers cultivating the crop, and by 1831 the tobacco plant was being extensively grown in County Wexford in particular. This was most likely due to the favourable conditions that prevailed there climatically and agriculturally. A twentieth-century pioneer of tobacco cultivation in Ireland often claimed that the greatest obstacle to the growth of the crop in Ireland was never climatic but rather political, and in 1832 a prohibition act specific to Ireland was passed in Westminster and all growing of tobacco was halted.

Resurgence

Gearóid Ó Faoleán  from Limerick in his report tells us that there was a resurgence in the 1930’s.  “The spirit of self-sufficiency that pervaded Ireland under de Valera in the 1930s led to the last significant flowering of tobacco cultivation in the country. The government of the time decreed that, henceforth, cigarettes were to contain a percentage of native tobacco.” 

Tobacco experts such as Kentuckian G.N. Keller, who had come to Ireland in an official capacity almost 30 years before, were on hand to facilitate this new project, and by 1934 some 750 acres of land were under tobacco cultivation in counties Wexford, Carlow, Laois, Kildare, Kilkenny, Meath, Wicklow and Offaly. It was a popular crop, according to Meath county councillor J.P. Kelly, who stated in 1934 that ‘people who grow tobacco had made money beyond their dreams’. The knock-on effect of this industry could be seen in Belfast, where tobacco-processing was one of the only industries that actually expanded during this period; the number of people employed in this industry increased by up to 30%.

There was serious money to be made. Increasing numbers of farmers now sought to introduce tobacco onto their land. Alarmed, the government responded by introducing strict new legislation concerning the price paid for tobacco and restricting growing permits only to those who had taken part in the 1933 growing season. The experiment in significant tobacco self-sufficiency was at an end.  

Home Grown Tobacco

Growing tobacco plants seem to come with a load of health warnings. I would be growing it for a pest deterrent and wouldn’t even consider smoking ANY deadly pesticide.

There are even warnings on touching the plants. One book tells me “First, be careful handling fresh tobacco leaves.  Touching wet leaves can cause green tobacco sickness, a type of nicotine poisoning.  The sickness frequently affects tobacco harvesters, usually migrant workers lacking adequate protection.” 

And it probably wouldn’t be very good to have them in the garden with children around “Children exposed to high levels of nicotine from wet leaves often require hospitalization. “ Challenging stuff indeed.

Low Profile

I have found out that if I am to grow tobacco in the tunnel, I first need to apply to Irish Tax and Customs at the local Revenue Office for a licence. So we’ll say no more about it, and if anyone asks, you haven’t seen me.

Perennial Nastrurtiums

I’ve been looking for “Jobs to Do” this week in the garden.  The weather has been a bit warmer and although the long johns and hat are staying firmly on until the summer, it has been mild and dry enough for me to go out and at least do a bit of tidying as well as seeing what needs doing to welcome in the spring.

Spring Jobs to Do

I generally leave all of the seed sowing until the last minute. Generally I only plant seeds about one month after the recommended sowing dates on the package. This allows for our geographic northern location and cooler climate. Nature generally rewards me by having less seeds die off with botrytis, eliminates the need for any artificial light and heat and also gives me a chance to tidy up a bit before sowing. 

The polytunel is pretty much ready to go; all I need to do is expand the beds a bit as there isn’t much growing space n there at the moment because I got carried away with the carpet and black webbing. It’s just a simple matter of lifting it up and teasing the soil loose so I can plant seedlings so there’s no rush with that. 

I have a propagator in place in the tunnel with a transparent zip cover and have put some off shoots of chamomile plants in there for the time being. This is giving me a good idea how long it’s taking for plugs to dry out as well as getting me into the habit of going out and checking them every day in readiness for the seed sowing.

I’m finding that the ground is still too wet for grass cutting. It’s been so mild over the winter that the grass didn’t really stop growing. I won’t be trimming it back for at least another month though as it could do too much damage to the soil. 

I’ve managed to put off most things from my venture outside, but there is one thing I have done which has been on my mind for a while and that’s to dig up the perennial nasturtiums before the y take over the garden.

Perennial Nasturtium

Klaus gave me a few free perennial Nasturtiums (Tropaeolum tuberosum) two years ago and I happily planted them outside.  In the two years these prolific plants commonly known as Mashua, have taken over half of the vegetable patch. They grew up the pea and bean poles and managed to kill off everything they came into contact with. I wouldn’t have minded so much but they aren’t attractive plants either as the flowers appear just as the leaves go yellow at the end of the year.  

The tubers also seem to have the ability to pop out of the soil and throw themselves across the ground to every corner of the garden. I’m not sure if this is something they do themselves or if it’s the magpies in the garden playing football but it’s an efficient method of spreading around either way.

I have read that the Mashua tubers are edible. They can be cooked like potatoes or grate them onto salads. I would try it but for a couple of differing views.  Some say these tubers have an aphrodisiac quality and others say the opposite, that they have an anaphrodisiac effect. It’s said the tubers used to be given to the Inca armies “that they should forget their wives" I won’t be cooking them up any time soon.

The cultivar 'Ken Aslet' has gained the Royal Horticultural Society's Award of Garden Merit, so it can’t be all that bad, but I’ll bet it wasn’t grown in the veggie patch.  

After an hour of gentle troweling I have managed a whole basket of the tubers and I don’t really know what to do with them. Should I give them away to friends? Throw them in the hedgerows? Sell them on ebay?  I just don’t know, but if we have a late frost I won’t have to give this another thought and needn’t have to make any decisions at all as they are just open to the elements.  And if the frost doesn’t get them straight away, the magpies will and have a good kickabout before the frost turns the tubers to mush and I can put them in the compost.

PS: I’ve just checked on ebay and the tubers are selling for £1 each…. I’m rich!  Thanks Klaus!