Grassland reseeding: establishment methods

Our decision tree will help you to decide which reseeding method to choose. We’ve also got information on using a pre-cultivation spray and results from our reseeding survey.

Back to: Establishing grassland reseeds

Which establishment method should I choose?

Achieving a level, uniform seedbed is important to ensure a consistent sowing depth. It is vital to select the right technique to suit the farm and soil conditions. Under correct conditions, the impact of reseeding technique on sward productivity is small. 

Recent research undertaken in Ireland has shown comparable yield benefits to reseeding with discing, one-pass cultivation and ploughing (see graph below). 

Results from Irish work on the impact of cultivation technique on grass yield 

Choosing the correct cultivation technique

Cultivation technique can be selected based on various factors, such as soil type and existing sward conditions. The cost of the technique needs to be taken into consideration. Each technique has several advantages and disadvantages. 

A decision tree for choosing a cultivation technique 

Example costs of different reseeding techniques (£/ha) 

 

Full cultivation

Minimum-till cultivation

Overseeding

Soil analysis

3

3

3

Spray

30

30

 

Spraying

27

27

 

Plough

61

 

 

Power harrow

50

50

 

Power harrow

50

 

 

Land leveller

17

17

 

Seed

161

161

79

Sow

22

79

79

Roll

17

17

17

Fertiliser–100 kg 18:14:14 + spreading

94

94

94

Lime-2 t +application

126

126

126

Leatherjacket control

12

12

12

Slug pellets

20

20

20

Total cost (£/ha)

689

636

430

The pros and cons of cultivation techniques 

 

Pros

Cons

Ploughing

Good seed-soil contact

 

Can remove compacted layers in topsoil

 

Achieves level even seedbed

 

Buries pests and trash

 

Most reliable method

Expensive due to the number of cultivations

 

Deep ploughing removes nutrient-rich soil from surface

 

Light soils can dry out quickly

 

Disturbs seed bank of weeds in soil

Minimum cultivation, e.g. discing, one-pass

Cheaper than full plough

 

Fertile soil remains at surface

 

Limited disturbance of soil structure

Difficult to remove trash

 

Decaying trash can release organic acids, hindering germination

 

Takes longer to achieve an even level finish across field

Direct drill into existing sward

Opportunity to maintain existing sward

 

No cultivation reduces costs

 

No disturbance of soil structure

Hard for cultivars to compete against existing sward

 

Not suitable for dry, hard ground

 

Results can be variable

Pre-cultivation spray

Before reseeding, applying herbicide to the existing sward can remove any existing weeds and reduce competition for the new ley. Trials undertaken in New Zealand achieved a plant count of 400 plants/m2 in the reseed when using a pre-cultivation herbicide. This was reduced to 120 plants/m2 when the herbicide was omitted.  

It is important to allow sufficient time between herbicide application and sowing the seed.

  • Contact between the seed and chemical may negatively affect germination rates
  • Cultivations can usually begin seven to ten days after spraying, but it is important to check the product recommendations 

Pesticide legislation 

Everyone applying pesticides is required to have a certificate of competence and the sprayer must have passed a test. More information can be found at: voluntaryinitiative.org.uk 

Always wear appropriate protective clothing and take care when handling pesticides. More information can be found at: hse.gov.uk/pesticides

Reseeding survey results

A survey looking into current reseeding practices on farm was conducted by AHDB during 2016, with technical assistance from Field Options. Some of the findings from the survey show:

  • Before reseeding, 58% of respondents treated the existing sward with glyphosate
  • About 46% of respondents ploughed and cultivated, another 19% cultivated but did not plough
  • Around 12% surface-seeded, with about 10% using a direct drill

Useful links

Grassland reseeding: top tips for ploughing, cultivation and overseeding

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