HEMP: THE CROP OF THE FUTURE


Pauline Lloyd

Reaching over four metres in height, hemp (Cannabis sativa) is annual that is closely related to the hops plant. Native to Central Asia, man has widely cultivated and used hemp in a myriad of ways all over the world ever since prehistoric times. The Vikings, for example, used hemp fibre to make cordage and up until about 1850 most of the world's paper was also produced from hemp. Records show that hemp was being cultivated for its fibre in China as early as 2800 BC and that the ancient Chinese were eating hemp seed up to 8000 years ago.  Throughout history hemp seed has also been recognised as having medicinal properties and it is still grown for medicinal purposes today in places such as India, the Middle East and Mexico.

However, despite being used for centuries in so many different ways, hemp eventually started to fall out of favour. Other natural and synthetic fibres were increasingly used in its place. Furthermore, a smear campaign in the US in the 1930s badly damaged hemp's reputation, causing a further decline in hemp use. People started to regard hemp as 'the killer weed' and new drug legislation meant that it then became illegal to grow hemp in many countries. It is still illegal to grow hemp in some countries today. Whereas in other countries (e.g. countries in the EU) a government licence is needed by anyone who wishes to cultivate hemp.

Fortunately, since the 1990s, there seems to have been a revival of interest in the hemp plant, perhaps as the result of increasing environmental concern. Between 1990 and 1997 hemp cultivation for food and fibre more than doubled and vigorous attempts are now being made to promote its use once again. Many organisations, including the Hemp Food Industries Association, Hemp Industries Association and Hemp Plastics (UK) are carrying out research and new hemp products are being developed and coming onto the market all the time. Hemp's outdated, rather 'hippy image' is rapidly being replaced by a new 'green image' as people start to realise hemp's potential as an environmentally friendly resource. For as well as being an excellent food crop, hemp has many other practical uses. It can, for example, be used to make paper, textiles, plastics, beer, cosmetics, paint, insulating materials, biofuel and also for animal feed and animal bedding.

Hemp is an excellent crop to grow: it doesn't require much water; it's unpalatable to most insects and it grows so quickly that weeds have little chance of taking over. Thus, it can be grown sustainably and largely without the use of pesticides and herbicides. Hemp is also ideal for use in a crop rotation system because its long root system conditions the soil for the crops that follow on afterwards. A further advantage is that it will grow in most types of soil and in most climates, making it an excellent crop for growing on otherwise unusable land.

Many different hemp cultivars are now available, the most important cultivar probably being the short, seed-producing crop FIN-314 (Finola), which grows up to 1.5 metres in height and is used for food production. This early blooming, frost tolerant and drought resistant variety is very easy to harvest and its seeds contain more oil and protein than other hemp varieties. It will grow in the UK, but as it has not yet been approved by the EU it has to be grown here without subsidies.

Hemp as a Food

Of exceptional nutritional value, hemp seed is often regarded as a 'super food'. A very good source of highly digestible protein (25%), fibre, essential fatty acids, vitamins and enzymes, it also contains appreciable amounts of the minerals zinc, calcium, iron, magnesium, manganese, phosphorus, potassium and sulphur. Hemp seed oil is unsaturated and contains the essential fatty acids, Linoleic (LA) and Linolenic acid (LNA), in what is often considered to be a nutritionally balanced ratio of 3:1. Essential Fatty Acids (EFAs) are necessary for human health, being involved for example in keeping the immune system healthy, in the maintenance of hormonal balance and in the formation of cell membranes. However, because the human body is unable to make its own EFAs it is important to ensure that  an adequate daily supply of these vital substances is obtained from the diet.  Hemp seed is ideal for this purpose, for as well as providing both EFAs it also contains respectable amounts of gamma-linolenic acid (GLA) and stearidonic acid (SDA). Gamma-linolenic acid can have a cholesterol-lowering action and clinical trials have also shown that it can improve premenstrual syndrome (PMS).

At the moment, there seems to be considerable enthusiasm for consuming hemp food products, which are incidentally available from health food stores, some supermarkets and by mail order. Whole hemp seeds have a nice crunchy texture and a nutty flavour and are easily incorporated into a vegan diet. You could, for instance, simply sprinkle some whole hemp seeds onto desserts or salads or alternatively you could try out my sunflower and hemp bar recipe (see below). It is also possible to purchase hemp seeds that have been hulled, leaving only the soft part of the seed. This 'soft seed' is higher in protein, has a nutty taste and soft feel and can be sprinkled over salads and other favourite dishes and may be more suitable if you find that the whole seeds stick in your teeth, or are not well digested. Another way of adding hemp food products to your diet is to buy a cold pressed hemp seed oil. (The suggested intake for an adult is one to three tablespoons of hemp oil each day.) Greenish in appearance, hemp oil is very tasty and is ideal for use in salad dressings, but it should never be heated.

Whole hemp seeds can of course simply be sprouted and blended with water to make a nutritious hemp milk. This hemp milk can be added to tea or coffee, or it can be flavoured and made into shakes or smoothies. Alternatively, it could be converted into hemp yogurt or tofu in much the same way that one would make these items using soya milk. Sprouted hemp seeds are also often baked with other sprouted grains in a low oven to produce sprouted breads. Additionally, ground hemp seeds can be added to smoothies, made into hemp butters, or simply sprinkled onto salad, cereals, or steamed vegetables for extra protein. If you are going to grind your own hemp seed, then grind it in a coffee grinder just before you want to use it in order to ensure that it is fresh.

In addition, many ready-prepared, vegan, hemp products are readily available from large supermarkets, health shops and by mail order from companies such as Hemp Union. Look out for hemp ice cream, tubs of toasted hemp seed, hemp flour, hemp burger mixes, sprouted hemp bread, hemp pasta and hemp pesto sauce. Experiment with these products and above all enjoy eating them!

Sunflower & Hemp Bar Recipe

Ingredients:
 Method:
  1. Mix the dried ingredients together in a bowl, then add just enough water to bind the mixture together.
  2. Tip the mixture out onto a plate and press it together firmly with your hands.
  3. Cut the dough into 4 bars.
Note: These bars can be stored in an airtight container in the fridge for a few days. They are usually firmer to eat, if they are made the day before.

Serves 4

Other Uses

As well as being a wonderful addition to the human diet, hemp has many other functional uses and I am now going to cover these in more detail:

1. Paper: Hemp is readily turned into paper. Quite a few hemp paper products are available by mail order including: A4 paper, envelopes, writing sets, pads and cigarette papers and some books are also now being printed entirely on hemp paper. Hemp can also be made into cardboard, filter paper and even bank notes and tea bags. Hemp paper production uses less polluting bleaching agents than traditional paper making processes and whereas trees can take 20 years to mature, hemp pulp can be produced in as little as four months. In addition, hemp produces more pulp per acre on an annual basis than trees.

2. Textiles: Hemp has been used to make strong, breathable and hard wearing clothes since the beginning of recorded history. In fact up until the early 19th Century, eighty percent of all textiles, clothing, fabrics, tents, bed linen and towels were made from hemp. Hemp is now being widely grown to produce textiles once again, although these days it is often mixed with other textiles such as cotton, silk, lycra and flax. Hemp is a much more environmentally friendly product than cotton, requiring little or no pesticides for its production. Various items of hemp clothing are available, Hemp Union being the main supplier of hemp clothing in the UK. The Natural Collection also offers a few items of clothing in its catalogue.

3. Plastic: Conventional plastics are produced using oil, which is a non-renewable resource. Hemp plastic has great potential as a sustainable alternative to such petro-chemical based plastics. First of all hemp is a completely renewable resource and secondly if a 100% hemp plastic product could be developed it would be biodegradable and could be composted after use, unlike traditional plastic which usually ends up as landfill. Research is being carried out into hemp plastic by Hemp Plastics (UK) Ltd. So far they have managed to produce a 25% hemp plastic product called 'high fly', which is a mixture of hemp and recycled plastic waste. They are also looking into hemp starch, which could be used to produce a 100% biodegradable hemp 'plastic' film that could be turned into biodegradable 'plastic' bags, containers for storing cosmetics in and other film and wrapping products. To find out more about their work visit Hemp Plastics (UK).

In addition, the National Department of Plant Production at the Danish Agricultural Advisory Centre has been using plant fibres (particularly fibres from flax and hemp) to develop fibre mats using a special air forming technique. These mats can be used in insulation products and in thermoplastic composites. For insulating purposes the mats are made using 95-98% plant fibre and 2-5% synthetic fibre but harder composites are also being developed that contain a higher proportion of plastic-fibre polymers, which could be used in the motor industry, for example in car interiors and exteriors.

An interesting paper by Karus and Kaup in the Journal of Industrial Hemp (Vol. 7: 1, pp. 119-131, 2002) examines the use of natural fibres (flax, hemp etc.) in the European Automotive Industry. This survey shows that hemp usage in the German (and Austrian) automotive industry seems have increased by as much as 90% over the last four years and also forecasts that the demand for natural fibres should also increase in other European automotive industries, as well as in those in North America. This is very good news because by substituting hemp fibres for glass fibres in composites, it should be possible to considerably reduce carbon dioxide emissions. At the moment, typical uses for natural fibre composites in the automotive industry include: door inserts, hat racks, boot linings, seat backs and parcel trays. In the future it is possible that they could also be used in bus, train and aeroplane construction as well.

Last but not least, Hemp Music Productions have just released an exciting new Hemp Plastic CD. This CD has been recorded at the Cutting Edge Studios in Australia. What is interesting about this new product is that all of the musical instruments used to make it are made from 100% hemp stone. What's more the CD tray is made from hemp plastic and has hemp paper inserts supplied by the Living Tree Paper Company. See the review, to find out more about this product.

4. Cosmetics: Hemp oil is high in polyunsaturated fatty acids and its moisturising properties make it the perfect base for cosmetics. It is especially beneficial for dry skin. If you want to try out some vegan, hemp cosmetics, then all of the cosmetic products sold by Hemp Union are vegan and carry the Vegan Society trademark.

5. Fuel: Could hemp be the sustainable fuel of the future? Hemp oil can be modified by a transesterification process to produce an oil with almost identical properties to diesel. Biofuels produces less smoke and carbon monoxide emissions than fossil fuels and virtually no sulphur dioxide.

6. As a Mulch: The Eil and Tasmanian Institute of Agricultural Research has been researching the use of hemp straw as a mulch for use in orchards. Both the bast and the hurd are highly absorbent and good insulators and make excellent mulching material. Trials on apple trees in Tasmania have shown that the hemp mulch compared well with other mulches, both in terms of soil fauna and in fruit quality. It is also thought that a hemp mulch could be useful for stabilising sand dunes that are liable to erosion.

7. Animal Uses: Because hemp is very absorbent it is often used as animal bedding in the UK. Hemp seed cake is produced as a by-product of oil pressing. Consisting of the husks of the hemp seed, it contains 30-50% protein and quite a lot of fat and is frequently used as animal feed. Though out Europe and Asia, hemp seed is often given to caged birds and is especially useful for raising game birds and racing pigeons. Hemp is well renowned in the fishing industry as a trusty bait. Fish, especially carp, are supposed to really swim for it. Watch out fish!

8. Construction: Hemp products are widely used in house building, especially in France. Hemp can be used as a concrete substitute and hemp medium density fibreboard can be used in place of wood.

9. Hemp Seed Oil: Hemp's oil is used in the manufacture of soft soaps, paints and varnishes.

10. Fibre: Hemp is still used to make rope, twine, nets, sacking and carpet warp.

Further Reading:

  1. HEMP: Healthy Eating Made Possible by Paul Benhaim (Fusion Press, 2000).
  2. Journal of Industrial Hemp (Vol. 7: 1, 2002), produced by European Industrial Hemp Association (Haworth Press, Inc., 2002).
  3. The Hempnut Health and Cookbook by Richard Rose and Brigitte Mars (HempNut Inc., 2000).

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