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Why Sainfoin is known as 'holy hay'

Why Sainfoin is known as 'holy hay'

What makes sainfoin so beneficial?

Sainfoin (Onobrychis viciifolia) has amazing properties and was largely ignored during the post war years of industrial agriculture. Not surprisingly, it’s making a bit of a comeback. 

What sort of plant is sainfoin?

It's a perennial legume that thrives on thin chalk, limestone or stony soils typical of the South Downs and the Cotswolds.

It's attractive large spikey pink flowers bloom in early summer and are a magnet for insects.


Image shows sainfoin growing at Honeydale Farm near Chipping Norton in the Cotswolds. Taken by Sally Morgan

What are the benefits of sainfoin?

  • Natural wormer  – sainfoin provides effective worm control when fed to livestock as it disrupts the worm’s life cycle.
  • Protein source – sainfoin contains condensed tannins which bind to proteins and protects them as they pass through the rumen, allowing them to be digested and absorbed, something that does not happen with other legumes. This gives rapid liveweight gain, so young stock can be finished sooner with a good carcass grade. The presence of the tannins means that sainfoin, despite having a lower N content than lucerne, has a high nutritive value. Also, the condensed tannins reduce enteric production of greenhouse gases, such as methane.
  • Bloat-free – sainfoin, unlike other legumes, does not cause bloat due to the presence of the tannins, and research has found that as little as 20% sainfoin in the diet can reduce the risk of bloat to virtually zero.
  • Soil nutrients – sainfoin is a nitrogen fixer, so  Rhizobia in root nodules of sainfoin fix nitrogen and boost soil nitrogen. The roots penetrate to great depths and pull nutrients up from the subsoil. Sainfoin has been found to increase the sequestration of nutrients such as phosphate. It is the ideal crop to sow ahead of cereals or brassicas in the rotation.
  • Drought resistance  – it can be grown on thin, highly alkaline soils and is extremely tolerant of drought due to its deep rooting nature, growing through dry periods. It is ideally suited to stony brash and chalk, but does not thrive on heavy wet soils with a pH below 6.2
  • Wildlife value – with its extended flowering period and the fact that sainfoin produces more honey than any other legume makes it invaluable to pollinators, attracting a wide range of bumble and honey bees, butterflies and many other invertebrates. Bees feeding on sainfoin produce higher yields of honey.


In 2013, Henry Edmunds from Cholderton Estate wrote about 'holy hay' for Organic Farming magazine. Here's his article:

Sainfoin  - a unique forage legume

How joyous the pastoralist wading through the pink effervescent glowing of a crop of flowering sainfoin in early June.  The very air steams with colour and is blurred by the all-pervasive movement of myriads of insects. Bumblebees droning from flower to flower, alighting and bending the delicate stems with their weight. Butterflies flip flopping in their dozens, while many smaller invertebrates crawl and scurry through this riotous beauty.

A plant of myth; murmurs from Seth, the aged shepherd bent over his beer in the local pub; he remembered the days of his youth, when the sheepfold crept over the sainfoin as it came into flower and the lambs that poured into the forward pen as the hurdles were moved on and the creep opened up.  The lambs were voracious with the flowering heads and grew so fast that this could be seen on a day by day basis.

Holy hay

Sainfoin, or holy hay, is a plant incomparable for the wellbeing of the animals that graze upon it.

It is a plant long recognised for its attributes but abandoned by the whims of a modernist agriculture seduced by cheap (as was) fertilisers and purging of ancient knowledge by a younger generation so keen to put aside the old ways that ‘progress’ became an exercise in iconoclasm. 

Unfortunately, the agricultural industry has been submerged by propaganda promoted by international agrochemical corporations where all the compounded benefits of traditional crops, in soil fertility, organic matter, nitrogen fixation, animal health and productivity were discounted. 

There is no profit for corporations in a farming industry based on fertility building, sustainability and self-sufficiency.

Quality forage

Sainfoin will produce good yields of hay on the poorest of soils with minimal input.

One can expect two tonnes of hay to the acre and it is possible to achieve three tonnes in a good year.

The hay, if carefully made, is of unrivalled quality and was, when available eagerly sought after by the racehorse fraternity.  At least a week of good hot weather is needed to achieve this, something that has been lacking in recent years. The crop should be cut when the plants are in full flower.  In tricky conditions, silage can be made instead.  The crop should be allowed to rest after cutting and can then be grazed again in the autumn. 

Sainfoin does not have the recovery that one sees with lucerne, but it grows away much earlier in the spring and will, because of its unique characteristics, prevent bloat. 

A natural wormer

Sainfoin on the chalk downs was the mother lode of all these attributes and the economic backbone of farms on the alkaline soils of Britain.

The Marie Curie Foundation ( has recently commissioned a whole plethora of research into this plant and has tested many strains from different parts of Europe.

They have discovered clear indications that the complex bio-chemistry of the leaves has a profound impact on the worm burden of grazing stock and that the complicated tannins within the plant substantially improve the utilisation of protein.

Sainfoin is also rich in omega fatty acids that have a positive impact on animal health and reduce methane emissions.

Boosting biodiversity

Undersown fields have proven to be havens for rare cornfield plants.

Two years ago, I witnessed the extraordinary spectacle of 8,000 plants of the beautiful night-flowering catchfly (Silene noctiflora) in one field together with rough poppy (Papaver hybridum) and some rare fumitories.

These plants all disappear in the subsequent year, but were able to seed to guarantee the next generation when the opportunity arises.

The compounded benefits of Sainfoin will ultimately be recognised. It will play an important role in the rebuilding of biodiversity and fertility in a landscape that has been despoiled and degraded by a generation of agriculturalists who have discarded a crop that could ultimately prove to be their salvation.

sainfoin flower

Establishing sainfoin

Sainfoin leys last four years or more and sometimes much longer.

It must be sown on land to which it is suited, that is one land that is free-draining with a pH of 6 or more. It thrives on thin chalk, limestone and sandy soils as well as stony brash seen in the Cotswolds.

Sainfoin is usually sown in April - May but it can be sown as late as August.  A high seed rate is recommended due to the large seeds, at rates of 65 - 100 kg seed per hectare (25 - 40 kg per acre). It may need an inoculant it if has not been grown previously on the field. One of the easiest ways to establish sainfoin is to under-sow spring barley (at 50% of its normal rate) at a seed rate of 27 kg sainfoin, 4.5 kg meadow fescue and 1 kg timothy to the acre. It is best mixed with these grasses as they are relatively uncompetitive and they do not shade out the sainfoin plants over the winter.

The grass also prevents couch grass infestation to which sainfoin can be vulnerable due to its open habit.  The grasses benefit from the nitrate exuded by the Rhizobia growing on the roots of sainfoin, and it is this combination which will ensure excellent yields of high-quality forage for many years. 

It takes a year to get established so ideally in the first year it must not be grazed, or if necessary lightly grazed in autumn, and left ungrazed through winter.

Henry Edmunds FRES is the owner of Cholderton Estate.