This week, farmers across the country flooded to the fields to kickstart the 2019 silage season.

This was brought on by the sunny, dry weather with exceptionally high temperatures – reaching 22° in some areas.

Monitor swards

For farmers who didn’t cut, they should be going out and examining their closed paddocks to see what growth stage they are at – to determine whether or not they are fit for harvest.

Grass growth rates will be hitting between 80-100kg DM/ha in a lot of areas this week, so you need to be mindful of this when determining the harvest date.

The quality or the dry matter digestibility (DMD) of your silage will depend on how much leaf and how little stem, seed heads and dead herbage are present in the sward when it is harvested.

However, poorly preserved silage can cause a reduction in silage quality, even if grass quality was good at harvest.

Plan harvest date

The target should be to harvest first-cut silage before the end of the first week in June.

The heading date of the ryegrass also has a role to play in determining the cutting date of the sward; you should be aiming to cut before the seed head begins to emerge on the grass plant.

Intermediate-heading varieties will begin heading out in the second half of May and late-heading varieties in the first half of June.


Farmers commonly delay cutting because they are waiting for the nitrogen (N) that they have spread to be used up.

When trying to determine if the N has been used up by the grass plant or not, Teagasc recommends going by the rule of thumb – “silage uses two units of N a day”.

Although, the crop can be cut earlier if weather conditions are dry and sugar levels are good (above 3%).

However, Teagasc also recommends “to test a sample rather than wait for the N to be used up”.


The sunny weather and the high temperatures will provide ideal wilting conditions for a mowed sward.

Farmers should aim to wilt the grass as quickly as possible post-mowing to limit sugar losses.

The problem is, as soon as grass is cut, sugars start declining because they are being used up by the plant – since it is still living – and by undesirable bacteria.

Therefore, the aim should be to wilt as rapidly as possible to an ideal target DM of 30-35%.

From an environmental point of view, wilting the grass reduces the amount of effluent produced when it is stored.