With the promise of high yields of exceptional quality silage from little or no chemical nitrogen, interest in red clover is very high. According to Germinal, demand for red clover seeds has increased twelve-fold since 2019. What was once a niche is now becoming more mainstream.

However, red clover is not without its challenges, and in my view it is still a relatively niche option on most farms. Soil fertility is probably the biggest limiting factor for red clover, followed by the fact that it can’t really be grazed.

This means that it’s only really suitable for silage fields that don’t ever see livestock.

Any field that is continuously cut for silage will have a high nutrient requirement compared to fields that are occasionally grazed.

This is because in a grazing scenario, a lot of the nutrients are reapplied by animals in the form of urine and faeces. So red clover needs lots of slurry or lots of chemical phosphorus and potassium, with red clover taking off 80 to 120 units/acre of phosphorus and 200 to 240 units/acre of potash annually for a 12t DM/ha annual yield.

While some nitrogen can be applied in spring for the first cut such as 50 units/acre, no nitrogen is required for subsequent cuts.

Red clover after being zero grazed to dairy cows last autumn.

With such high P and K requirements, it’s an expensive crop to grow – even though it uses very little nitrogen. Even where slurry is being spread, there is still an opportunity cost of putting it there, especially where there are other parts of the farm that have low soil fertility.

According to Diarmuid Murphy from Germinal, most farmers will take the first cut in or around 15 to 20 May and it will be mostly grass, with not much clover present.

The second cut will be taken in early July and will be about 50:50 in terms of grass to clover content, while the third cut in September will be nearly all red clover. In terms of flowering, he says you cannot stop the third cut from flowering.

The fourth and final cut can be tricky because of the time of the year it will be cut at – late October and November. Because red clover is harder to preserve than ryegrass, the advice is to either take a light grazing off with cattle at the back end, or zero graze it.

Soil type would need to be good to be able to drive a zero grazer on it at that time of year.


Persistency is another problem with red clover. The best case scenario is that it will last for four to five seasons before dying out.

What is left is essentially just ryegrass and white clover, if that was sown as part of the mix. The general advice is to keep red clover fields on a 10 year reseeding programme, which means that for five or six years of that cycle it’ll be mostly ryegrass and white clover as opposed to ryegrass and red clover. This could also be important from a disease and pest prevention point of view.

Fitting red clover into a rotation won’t be easy on many farms, even those with dedicated silage blocks. The cutting dates for red clover swards are also different than those for traditional one-or-two cut silage systems.

Sowing date and soil fertility is hugely important, with most advice now geared towards spring sowing for red clover. If soil fertility is poor or deteriorates during the lifetime of the crop, it will shorten the life of red clover.

Despite these apparent drawbacks, the feeding quality of red clover silage is very good – about three percentage points higher in crude protein than grass silage.

Diarmuid Murphy recommends farmers to use a disc mower without a conditioner to cut red clover and not to ted it out as this will knock off the high feed value leaves. He says a good wilt of up to 48 hours is important.