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Growing Winter Rye in Scotland

10 May 2023

In recent years winter sown hybrid rye has become the crop of choice for anaerobic digestion plants to produce bio-gas due to its high dry matter yield in the field and methane production. The growing of the crop for this use has caught the attention of other farmers and growers who are looking to see if rye has a place in their arable rotation or livestock enterprise. 

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Winter Rye at a Glance

Winter Rye: What You Need to Know

Winter sown rye has the potential to be used to provide early grazing in the spring, to be cut as a wholecrop silage or to be left to mature and harvested for grain and straw. There are also emerging markets for flour and distilling. 

Winter rye is a short lived annual which is sown in the autumn. Seed rates are lower than other cereals with a target plant of 200-250 plants/sqm. ADAS produce a recommended list with seed supplied through KWS and Senova.  

Fertiliser Requirements

When grown as a grain crop, nitrogen N-Max allowance in an NVZ area is 180kgN/ha following a white crop. Most of the growers contacted for this article were applying much less with a range of 70 -150KgN/ha (excluding organic manure). The higher application rates are required when rye is cropped for more than one year from the same field. 

The straw has a higher potash content and removes greater amounts of phosphate and potash especially when taken as a wholecrop. 

Phosphate and Potash Content (fresh weight
at 15%MC)

Rye Grain & Straw8.611.8
Wholecrop Rye1.85.4

Phosphate and Potash Removal

Yield t/haPhosphatePotash
Grain & Straw977106


Rye is particularly susceptible to Brown Rust which can significantly reduce yield. Mildew, Rhynchosporium, Ramularia and Septoria can also affect the plant, but rye is generally less suspectable to these foliar disease as well as root and stem disease Take-All and Eyespot. As a cross pollinator rye is susceptible to Ergot which can be an issue to livestock when grain is fed on farm. 

Growth Regulator

The rapid growth and tall plant height require a minimum of two plant growth regulators applications to shorten and reduce lodging risk with a third application recommended to shorten internodes when taken to a mature crop. 


Winter rye matures earlier than wheat. Harvesting forward speed is significantly reduced due to the large bulk of straw being fed from the table to the drum. Grain separation is not an issue. 

Growing Winter Rye in Scotland On a Dairy Arable Unit

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Kelloe Mains Farm

Robert McDonald farms approx 1200ha in the Scottish Borders with the main production unit milking 700 high yielding dairy cows. In 2020 Robert was very disappointed with the performance of his 2nd wheat crops that were harvested as a wholecrop to provide home produced forage to complement the high quality silage also produced on the farm. In the 2021 harvest year Robert tried 26ha of winter rye as a “look-see” and has not looked back. For the 2023 harvest there is 81ha of winter rye in the ground. 

The Benefits of Rye vs Wheat

With an on-farm weighbridge the business is able to keep a close eye on yield and over the last two years has averaged 48 t/ha at 35% dry matter.  

Stability of yield and a higher yield is one factor, but it also cheaper to grow than the 2nd wheat crop and performs well on both light sandy fields as well as heavier sandy loam soils. The early growing crop requires less total nitrogen fertiliser with 60kgN/ha being applied at the start of spring growth and a further 50kgN/ha applied by crop growth stage 32. 

Pesticide inputs are restricted to two fungicides to protect the crop from Brown Rust. Importantly two applications of growth regulator are applied. 

A Difference in the Silage Pit

Harvest is by a self-propelled forage harvester and Robert comments “It is easier to clamp in the pit than wheat”. Harvest timing is late milk stage of the grain when a change in the colour of the lower stem can be seen. The early harvested land is sown back to rotational grass or winter oilseed rape. 

The Results

The wholecrop analyses around a 10ME energy and 9% crude protein with a 23-24% starch content. The wholecrop is mostly used as a base forage to feed young stock, heifer replacements and dry cows. 

Robert has also taken some of the crop to maturity and combined for the grain and straw. Yield in 2022 was 9.3t/ha from the same 110kgN/ha, starch content was 53% but in 2022 the protein content was surprisingly low at 6% protein where 9% is more normal. Robert comments that “combining a rye crop is much slower than wheat and at 2km/hr take patience and concentration to avoid choking the intake or drum”. 

Growing Winter Rye in Scotland as a Pig and Arable Producer

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Slighhouses Farm

Slighhouses is a pig breeding and finishing unit with arable cropping. The business process and mix their own feeds with nutrition advice and ration formulation provided by Harbro. Previously they have used home grown winter barley and wheat in their rations. Harbro have been developing the inclusion of hybrid rye in pig rations for several years due to the noticeable benefit on how the carbohydrate fraction is utilised in the digestive system and its higher lysine to protein ratio.  

Following discussions with their nutritionist Adam tried a field of winter rye in 2019. Since then, the acreage has increased each year and he has encouraged a neighbour to grow and supply him with hybrid rye. He finds it a more resilient and reliable crop which has consistently produced yields above 10t/ha on a range of soils with lower growing costs than wheat or barley.  

Rye as an Entry for Oilseed Rape

Rye fits well into their rotation and now provides an entry for oilseed rape. On the land farmed under a contract farming agreement they avoid following rye with a cereal crop, as volunteer rye can be an issue in other cereals. With years of pig FYM and slurry the fertility of the in-hand land is high and bag nitrogen is limited to 110kg/ha. No FYM, slurry or bagged P&K is applied to the rye crop. Growth regulator is applied at three timings. Cycocel at late tillering, Moddus at T1 and Cerone before flag leaf sheath opening. A low cost triazole fungicide is applied at T1 and triazole/SDHI at T2 provides foliar disease protection against rust. 

Harvesting Times

Harvest fits between oilseed rape and wheat. The rye threshes easily, but the drum need to be at its widest setting to accommodate the bulk of straw. The grain is dense, and sieves are opened wider and wind speed increased. The straw bulk means harvest progress is slow compared to wheat (less than 4km/hr). Table side knives help smooth the crop intake and because of the 10m cutting table a swath roller is used in front of the baler. 


In short, the introduction of hybrid rye has increased grain output, reduced the cost of home-grown feeds and the cost of purchased feeds without compromising pig performance. 

Growing Winter Rye for Biogas

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Waverley Farm Contracts

Waverley Farm Contracts is a wholly owned subsidiary of St Boswells Biogas which produces and injects over 3 million m3 of biomethane into the local gas grid each year. Bill Thompson is responsible for sourcing locally grown feedstocks to supply for the plant. 

Changing to Winter Rye

In the yearly years grass silage was the main feedstock, but more recently this changed to include winter hybrid rye (567ha in 2022) due to its higher yield both in terms of tonnes/ha yields and a higher yield of methane gas. Improvements in hybrid rye varieties has led to a longer ears with more grain sites and Bill believes this factor has boosted the gas yield. 

CropMethane Yield m3/tonne fresh wt
W Rye126
W Oats110
Grass & Clover82
Peas & Spring Oats137
Maize (not grown)100

Grass clover leys start the harvest in early June followed by wholecrop rye in early July and wholecrop winter oats harvested at the end of July provide the feed stocks. Wholecrop pea and oats are being tested as a spring sown feed stock and whilst has a lower crop yield Bill is encouraged by the higher methane yield. 

Rye is Popular with Arable Farmers

The switch to hybrid rye is providing a better rotational fit for the surrounding arable farmers, where it has replaced winter barley; as an entry for winter oilseed rape, and 2nd wheat. Inorganic nitrogen (with sulphur) is applied at 130-150kgN/ha depending on applications of digestate. Two growth regulators are applied with rates adjusted to ensure the crop remains standing, a key requirement for a speedy harvest which happens over a 10-day period at the start of July. Harvest timing is determined by the grain development stage and colour change at the base of the plant. The ideal dry matter is 36% but in reality, the 10-day harvest window means a range from 31-40% dry matter. A local contractor uses a self-propelled forage harvester to cut and chop the crop into a fleet of tractor hauled trailers which source through the local Borders Machinery Ring. Every trailer load goes over the weighbridge and yields range from 37- 45 tonnes/ha. As all the rye is weighed into the digester they have been able to see the benefit of using a ensiling additive. The biological additive is applied by the forager ensuring a rapid and stable fermentation in the clamp minimising energy loss and spoilage. 

Returning Waste Digestate to the Field

The waste digestate produced by the plant is spread back onto the land from which it was harvested returning the removed phosphate and potash. From a P&K perspective it is like a 0:14:40 fertiliser. It also returns a readily available source of nitrogen and provides a beneficial microbial boost and feed source to soil life to arable farm soils that lack a source of organic mucks and manures. 

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