Growing, processing, buying and selling thatching straw

Growing straw

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Choice of land and cultivations

The best thatching wheat is grown in deep, flat, well-drained but moisture-retaining, clay-loam soils of low to moderate fertility. Good crops can be grown on lighter soil if it is rich in organic matter. Wheat prefers a soil pH of 6-6.5 to grow well, and acid soils should be limed when necessary. Wheat land should be ploughed in the early autumn to 20-25 cm (8-10″) and cultivated at least twice, the second time just prior to sowing. Care must also be taken to ensure that litter from previous cereal crops, and any volunteer plants, are ploughed under in order to reduce the transmission of disease. The goal is to obtain a good seedbed with a open, friable texture that will allow the crop to develop a strong root system in the autumn. Wheat grown on land that has been heavily compacted runs a greater risk of lodging.

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Fertility

The best quality straw is grown using a low input approach and production methods that have not changed greatly since before World War II. A wheat crop needs a steady supply of nitrogen (N), phosphorus (P) and potassium (K) throughout the growing season, and an older variety grown in low input conditions will draw nutrients at a steady rate and produce strong, durable straw. In the past, soil fertility was maintained by fallowing and rotating cereal crops with legumes, grass leys and fallow. Fields were not heavily dunged because abundant nitrogen encourages lodging. Unlike most modern wheats, older varieties also formed symbiotic relationships with root fungi (myccorhiza) that essentially extended their root system and helped them cope with stresses such as drought and disease. Soil myccorhiza are killed by direct applications of fungicides and chemical fertilisers. Many thatchers and owners are willing to pay a premium for straw that has been grown in certified organic conditions, but simply converting to organic does not in itself guarantee that the straw produced will be suitable for thatching.

Traditionally, wheat was grown for 1-2 years following a crop of legumes, or after a grass ley, with a break of at least three years before another wheat crop. Nitrogen levels can be too rich after a long ley, so it is wise to grow a root crop immediately after the ley followed by one or two thatch crops, and then barley or roots before the field is returned to ley. The risk of ‘take all’ disease (Gaeumannomyces graminis) increases greatly in year three, and continuous production should be avoided as it has a negative impact on soil health and forces growers to use fungicides and a high-input approach.

A light dressing of manure can be ploughed under prior to planting, but fields should not be heavily dunged. Farmyard manure should be spread as evenly as possible to encourage even growth. Experienced growers find that small, regular inputs of well-composted farmyard manure improve soil texture and provide a steady source of nutrients for plant growth throughout the growing season. When composted manure is not available, green manures and legume crops should be grown in rotation and ploughed down.

Some growers insist on a light seedbed dressing of artificial phosphorus and potassium (P-K) fertiliser to encourage the development of healthy stems and roots. This would normally be applied at no more than 30 units (37 kg/ha) of P and 50 units (63 kg/ha) of K, although some growers double these values if no FYM had been applied the previous year. Unfortunately, added phosphorus will greatly reduce the activity of root myccorhiza, and in the long run reduces the natural health of the soil. Applying artificial fertiliser ‘down the spout’ at sowing time is not recommended on healthy soil, as anything that reduces the early development of a strong root system that can gather nutrients from a large ‘rhizosphere’ will have a negative impact.

For growers who insist on a conventional route, at sowing time no more than 20 units (25 kg/ha) of nitrogen should be applied to an old variety such as Little Joss, or 35 units (44 kg/ha) to a modern variety such as Maris Widgeon.

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Sowing

The best thatching wheats are winter varieties that need a cold period of a month or more in order to produce straw and set seed. Ideally, seed should be sown in early October so that the crop can become well established before winter. Many winter varieties can be planted up to early February, but yields will be lower. Straw production and flowering are controlled by day length, so that changing the planting date does not significantly affect ripening times. Late planting reduces the risk of disease, but a late sown crop will also have less time to mature and will produce lighter, and less durable, straw. Later sowing gives a grower more time to dispose of surface trash and control autumn-germinating weeds.

Wheat tillers in the spring, and too dense a planting will encourage strong competition between shoots and encourage the production of tall, fine, weak straw that is prone to lodging. Older varieties tiller more than modern varieties at low planting densities and in low nitrogen conditions. Most growers plant at 1.5 cwt/acre (188.2 kg/ha). It is better to sow thinly than thickly (in the autumn) in order to discourage disease and increase stem diameter. The seed rate should also be adjusted for reductions in germination rate.

Thatching wheat is normally planted in 15-20 cm (6-8″) rows depending on soil conditions and sowing date. Some organic growers prefer 25-30 cm (10-12″) spacings which allows for inter-row cultivation, and improves air circulation which reduces the incidence of mildew and other diseases. Modern drills can place seed at a standard 1.1-1.6″ (3-4 cm) depth so that the crop emerges evenly. A field is then be rolled with a Cambridge press roller, which removes air pockets and improves establishment. Conventional growers will apply a pre-emergent herbicide to kill weed seeds and seedlings immediately after sowing.

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Spring treatments

In the early spring, the thatch crop should be cross-harrowed with light chain harrows in order to kill weeds, even out the crop and stimulate tillering. The field should then be rolled to reduce the risk of lodging, and to press large stones into the soil so that they are not picked up by the reaper binder at harvest time. A warm winter or spring will stimulate rapid growth and increase the risk of disease, ‘dog-leg’ and lodging. Traditionally, growers grazed their fields lightly with sheep to check forward growth and stimulate tillering, and this can produce astonishing improvements in yield and quality. Only light grazing is acceptable, however, and this has to occur early in the season to avoid damaging the crop.

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Weed control

Weeds rob nutrients, and steal light which encourages stems to grow quickly and makes them thinner and more susceptible to lodging. They also add moisture to the sheaf, and increase the risk of straw ‘moulding’ in the stook and in storage. No thatcher wants to thatch with straw full of docks and thistles. Before the introduction of herbicides, weeds were controlled by crop rotation, frequent tillage, ‘stirring’ and grazing of the fallow and careful grain cleaning. Most straw growers apply a pre-emergent herbicide after planting or a post-emergent spray within six weeks of drilling, and spray again in the spring before the four leaf stage. Research has shown that herbicide sprays can interfere with wax production on plant surfaces, which will reduce the straw’s durability. Combing machines will remove most docks and thistles from CWR, but tall weeds are retained within LS.

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Disease control

Thatch crops are damaged by the same diseases that affect grain crops such as mildew, take-all, rusts and smut. Detailed information on all of these diseases, and chemical methods of controlling them, is widely available. Thankfully, most diseases will not cause major damage to a healthy crop of thatching straw grown in rotation from clean seed on healthy soil. Many diseases also cause more damage to the grain than to the straw.

Diseases generally strike more heavily in lush crops with a dense leaf canopy. Powdery mildew (Erisphe graminis), for example, can be reduced by sparser planting which improves air circulation. This will also reduce the rate of spread of pests such as aphids which open the plant to fungal attack. ‘Take-all’ disease (Gaeumannomyces graminis), which bleaches ears and stems and prevents plants from setting seed, is spread by a soil fungus that increases in virulence over a 3-4 year cycle. The best defences are to avoid continuous cropping of wheat, ensure that fields are properly rotated with disease-resistant crops, and not to plant too early.

Wireworm can devastate a wheat crop that is sown immediately after the break up of a grass ley. The ley should be broken up in the summer and worked up several times before planting in order to reduce the risk of infection. Stubble and trash should also be ploughed down as soon as possible after a straw harvest, unless conditions allow the rapid establishment of a clover ley. Every effort should be made to ensure that no volunteer plants survive to provide a ‘green bridge’ for disease to spread from year to year.

Many conventional growers apply at least one fungicide spray early in the growing season to help reduce the risk of fungal attack, but fungicides can interfere with natural wax production on leaf and stem surfaces, and thereby increase the plant’s susceptibility to further attack. Less wax will also reduces the straw’s water shedding ability and longevity. Growing mixtures of resistant varieties will slow the spread of viral and fungal diseases and help reduce their impact.

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Lodging

Lodging occurs when a stem buckles or bends at its base. In mild cases, the shoot turns up towards the light and continues to grow producing a ‘dog-legged’ stem with a kink or curve at its butt end when cut. Severe lodging will cause the straw to fall on top of other plants or onto the ground, which will prevent it from ripening and make it much more difficult to reap. Some reaper binders have ‘lifters’ which can help raise a fallen crop, but the lower quality of lodged straw usually prevents it from being used as thatch.

The risk of a crop lodging increases when the soil is compact and contains little organic matter. Varieties also differ in their resistance to lodging: large diameter stems with thick walls will not buckle as readily as narrow stems with thin walls. Dense planting, high fertility, and poor weed control will also encourage stems to grow quickly and increase the risk of lodging. A new grower should plant shorter varieties where there is a risk of lodging, and move on to taller, higher quality varieties or mixtures once he has greater experience and soil nitrogen levels have been reduced. Mixtures containing a proportion of short, lodging-resistant varieties can also provide a useful buffer on soils of uneven fertility. No matter what precautions are taken, a perfect crop can be flattened by strong winds and rain just before harvest.

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Field records

A wise grower will keep detailed records of his crops, cultivations and treatments, along with samples of straw and grain, in order to develop an understanding of the impact different treatments and inputs have on straw quality. Such records will also give householders and thatchers greater confidence in home-produced material. A successful roof is a testament to the skill of the grower as much as the skill of the thatcher.

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Processing straw

Cutting & stooking

Most of the thatching straw grown in the UK is cut with 19th century style reaper-binders. Most of the binders once used in Britain have rusted away in the abandoned corners of farmyards, but repairable machines can still be purchased at farm sales, and new canvasses, and instruction documents and technical guides, are available for all of the models in common use. Once in good working order, binders are reliable machines and some have been reaping over 50 acres of straw a year for more than 75 years. Some growers are now using tractor pulled or self-propelled rice harvesters, which do not have canvasses like reaper binders, and can therefore operate in damp weather. Some growers sell their standing crop to a thatcher who arranges the reaping, or contract the cutting to a reliable neighbour.

The timing of the straw harvest is critical. A common saying from the last century still applies: “if you think it’s ready to cut it’s a week too late.” Quality will plummet if the straw is left to ripen only two days beyond its prime. In the West Country, CWR will usually be ready to cut in early-mid July depending on the weather. It must be harvested several weeks before it would be considered ripe enough to combine so that the straw remains flexible. Growers look for a ‘rainbow’ of colours, or a residual band of light green tissue on the upper internodes, but varieties differ in how this colour-ripening phase progresses. A little moisture should come out of the stem when a thumbnail is forced up along the upper internode. The grain must be ‘yellow ripe’ or ‘cheesy’ (in the middle of the ‘dough development stage’), whereas grain producers combine their crops only once the grain is ‘dead ripe’. Grain will ripen perfectly well in the stook and in storage. Older varieties and mixtures ripen more unevenly and slowly than modern wheat, which can be a advantage in hot weather. Growing several different varieties will also stagger ripening times and allow the harvest work to be spread over several weeks.

The cutter bar of the reaper-binder is usually set to leave a 8-13 cm (3-5″) stubble, but can be raised is the soil is stoney, uneven or full of short weeds. The binder should tie sheaves into bundles no more than 20-25 cm (8-10″) in diameter so that they dry out quickly in the stook. A traditional reaper binder requires two people – a tractor driver and someone operating the binder. Assuming no breakdowns in machinery and good weather, an experienced operator can cut c. 7-10 acres of straw in one day.

Sheaves are placed in a stook to dry, and an experienced worker can stook at least two acres of wheat in a day. The heads of the sheaves must be locked securely together, but in a way that allows the wind to blow through them. The crop is left in stooks to dry for 1-3 weeks to ensure that it is as dry as possible before it goes into storage.

According to tradition, the best quality thatch was obtained from wheat that had been kept in a thatched rick until Christmas. Storage in a rick allows moisture to dissipate, and ‘conditions’ the straw making it easier to comb and thresh. PVC sheeting prevents the straw from ‘breathing’, and a good crop of straw can be ruined in just a few weeks if it is not stored properly. Most growers store the harvest indoors, usually in round bales compressed using a specially built ‘bundle clamp’. Straw should always be stored on pallets, and storage areas should be well-baited to reduce rodent infestations.

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Threshing (for long straw)

Threshing machines were very common in Britain before the combine harvester swept through the countryside in the 1940-50s. Like the reaper-binder, the threshing machine is an essential part of the tool kit required to produce both LS and CWR, and many different models were manufactured in the early 1900s. The core of the thresher is a steel drum that revolves at 1,000+ rpm against a stationary ‘concave’. The drum is usually 54″ (137 cm) wide and carries parallel rows of metal ‘beater bars’. The concave is a quarter section of a cylinder made of iron bars and wires and is partially wrapped around the drum. Straw fed into the mouth of the thresher passes through a small gap between the drum and concave, where the beater-bars of the revolving drum knock the grain out of the ears. The width of this gap is adjustable, and when properly set allows the straw to pass through relatively undamaged so that it can be used for LS. If the gap is too wide the crop will not be completely threshed. The threshed straw and grain passes from the concave onto a series of long wooden racks called ‘shakers’ that toss the straw upwards and forwards at each stroke. Ultimately, the ‘long straw’ is delivered to the rear of the machine where it is trussed or collected loose and stacked. Short straw and finer ‘cavings’ are blown out of the machine and can be used as fodder or animal bedding. A series of oscillating riddles and dressers remove chaff and rubbish from the grain, which is then delivered into sacks.

Threshing requires a team of at least five people: one person to load straw onto the upper box, a second to pass this straw to the feeder, the feeder who drops the straw into the mouth of the drum, a fourth to keep the thresher in working order and tie off full sacks of grain, and at least one more person to clear and stack the threshed straw. Feeding the thresher so as to minimise damage to the straw while maintaining a steady throughput is an art, and sets the pace for the entire operation. The straw is fed into the drum almost horizontally in order to minimise damage to the straw, and a drum less than 54″ wide is too narrow to cope with the longer-stemmed varieties used by thatchers.

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Combing (for combed wheat reed)

A greater leap forward occurred in the late 19th century with the invention of a ‘combing box’ that could be fixed over the drum of the threshing machine, allowing straw to be combed on an industrial scale. In the reed comber the threshing and combing operations are combined. Instead of passing through the drum, a series of belts carries the grain-bearing straw horizontally between a set of rotating spiked drums which strip away the grain, leaf, weed and short straw leaving clean, undamaged wheat reed. The combings and grain then pass through the drum and cleaning mechanisms of the thresher as normal. The combed straw is delivered to a trusser where it is bound into bundles (nitches) which are ‘butted’ onto a hard surface to align the butt ends. Some growers now use a hydraulic ‘bundle clamp’ to store combed straw in large round bales that can be moved efficiently with lifting equipment, but but still stack and move their reed by hand.

As with threshing, at least five people are required for an efficient combing operation and a larger team is recommended. An efficient team can comb over 1,000 14 lb (6.4 kg) bundles of combed wheat reed in a day. Straw is easier to comb after it has been stored for several months in a rick or a well-ventilated barn, and the key to good combing is to feed the straw into the mouth of the comber at a smooth and steady rate.

Several straw producers have built their own machines in recent years from detailed plans issued by the Rural Development Commission in the 1980s, but building a comber is an expensive and laborious undertaking and is not recommended for new growers. A portable combing machine has recently been developed which would allow smaller producers to comb their own combed wheat reed.

Some growers harvest their crops with a header stripper and swather. The header stripper strips the grain off the ripening stem while it is still standing in the field. The stripped straw is then cut, swathed and round-baled, and sold as either long straw or combed wheat, even though it has not gone through a threshing drum and has not been combed. Grain must be well-ripened in order for the header-stripper to work efficiently, and any delay in cutting the stripped straw will allow it to ripen even further and become very brittle. Many experienced thatchers and growers believe that header-stripped straw does not perform as well as traditional CWR or LS, and straw produced in this way should not be marketed as if it were the traditional product. Similarly, the drum of a modern combine harvester is too narrow to produce good quality LS, and will not remove grain as efficiently as a threshing machine.

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Yield

Traditionally, Devon reed was bundled into a ‘nitch’ of c. 28 lbs (13 kg) and was sold by the imperial ton which held c. 80 nitches. Somerset reed was usually sold in 14 lb (6.5 kg) nitches. Most thatching wheat varieties will yield between 1.2-1.6 tons (190-250 14 lb nitches) of processed straw per acre (2.9-3.9 mt/ha), and an equivalent amount of feed quality grain. Combing also generates leafy combings which can be used as fodder.

Three 14 lb (6.4 kg) nitches of combed wheat reed will cover one m2 of weathered thatch, and 29 nitches (406 lbs/185 kg) are required to thatch a traditional ‘thatcher’s square’ (Tsq) of 100 ft2 (9.3 m2). New work is applied a little more thickly at a rate of c. 4.6 nitches per m2, or 43 nitches (595 lbs/270 kg) per Tsq. Few thatched roofs are smaller than 6 Tsq (= c. 1.5 acres of straw), and additional straw is required for replacing stripped eaves and gables and for ridging. The figures for long straw are comparable. In practice, coverage will vary depending on the length of the straw, its taper, and the thickness to which the thatch is applied. A ton of Maris Huntsman provides greater coverage than a ton of Squareheads Master, and many thatchers will prefer to use a modern variety even though an older one may be more durable.

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Selling & buying straw

Large growers and dealers are now heavily involved in the production and marketing of both combed wheat reed and long straw throughout the UK, and can ship straw to any part of the country at short notice. Much of the combed wheat reed now used ‘up country’ is produced in Devon and Cornwall. Large West Country grower-dealers have helped smaller local producers find an outlet for their crop, and playing an important role in buffering seasonal fluctuations in price and availability. A new grower may decide that it is simpler to sell his crop to a local dealer, who will work with him to ensure the crop is grown and processed to a high standard. Many smaller growers prefer to sell their standing crops to a local dealer in order to avoid having to process, store and sell the straw themselves.

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Many thatchers purchase only from dealers they know they can trust, and many growers retain supplies throughout the year for their dedicated customers. Thatchers are always on the look-out for good quality straw available at a fair price, but most have limited storage facilities and cannot purchase all the straw they require for the year in advance. Unfortunately, there is no surplus production in the straw sector to buffer weather-induced price and quality fluctuations, and thatchers who have not built up a good relationship with their grower have paid extortionate prices for poor quality straw in recent years because of shortages. Straw prices can double in a bad year, which encourages thatchers to import straw and switch to water reed. Even in a good year, some thatchers will happily use very poor quality straw if it can be bought at a low price.

Combed wheat reed grown in the West Country sold for £ 800-1000 per ton (delivered) in 2008, but fell slightly to more normal levels in 2009. Long straw sells for £ 550-750 per ton in East Anglia.

Thatch is a low-input, but labour intensive, crop, but much of this labour may already be available on the farm or can be exchanged for goods or labour within the local economy. A recent survey indicated that an average crop of combed wheat reed can generate a net profit of £300-400/acre, not including the sale or farm use of grain and combings. Net profits can be higher than this on farms that have found ways of reducing labour costs and improving efficiency without compromising straw quality. A new grower must undertake a careful cost/benefit analysis before deciding to become a straw producer. Given the current state of agriculture and the prognosis for the future, the advantages will outweigh the disadvantages for many small and medium-sized growers, and particularly for those with storage facilities and cereal growing experience and equipment.

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