Grass Wedge Planner — A Complete Guide for UK & Irish Farmers
A grass wedge is one of the most powerful tools in rotational grazing management. It tells you exactly how much grass each paddock holds, which ones are ready to graze, and whether your farm has a surplus or deficit ahead. Here's everything you need to know about reading, building and acting on your grass wedge.
Quick answer
A grass wedge is a bar chart of paddock covers ranked highest to lowest. It shows whether paddocks are ready to graze, at surplus, or in deficit. Combined with Average Farm Cover (AFC) and your herd's daily demand, it tells you exactly how many days of grass you have ahead — and what to do if that number is too high or too low.
What is a Grass Wedge?
When you graze paddocks in sequence, the first paddock grazed at the start of a rotation has the longest time to regrow. The last paddock in the rotation has had the least time to recover. When you plot each paddock's cover from highest to lowest, the bars form a descending slope — a "wedge" shape.
The ideal wedge is a smooth, evenly descending line from your pre-grazing target (the highest paddock, ready to graze today) down to your post-grazing target (the most recently grazed paddock). Any paddocks sitting above the pre-grazing target line are in surplus — they've been missed or growth has been too fast. Any paddock below the post-grazing target is recovering after grazing.
What a healthy wedge looks like
Covers in kg DM/ha — UK dairy example, pre-grazing target 2,800 kg DM/ha
UK & Irish Grazing Targets by System
Pre-grazing and post-grazing targets vary significantly between UK (AHDB) and Irish (Teagasc) systems. Irish farmers typically operate at lower covers and higher grazing frequency to maximise leaf stage quality.
| System | Pre-grazing (kg DM/ha) | Post-grazing (kg DM/ha) | Target AFC (kg DM/ha) | Rotation (days) |
|---|---|---|---|---|
| UK Dairy (AHDB) | 2,800–3,200 | 1,500 | 2,000–2,500 | 18–21 |
| UK Beef | 2,500–3,000 | 1,200 | 1,800–2,200 | 21–28 |
| UK Sheep | 1,800–2,200 | 800 | 1,400–1,800 | 28–35 |
| ROI Dairy (Teagasc) | 1,400–1,600 | 50–100 | 900–1,100 | 18–23 |
| ROI Beef / Suckler | 1,400–1,600 | 100–200 | 900–1,200 | 21–28 |
Days of Grass Ahead Calculator
Days of grass ahead
20.7
days
Daily herd demand
1.4t
kg DM/day
Growth rate needed
34
kg DM/ha/day to break even
Typical Grass Growth Rates by Month
Grass growth rates vary enormously through the year. Spring flush in April–May typically produces 60–80 kg DM/ha/day in good conditions, while growth can fall to near zero in January and February. Understanding seasonal growth helps you plan when to close paddocks for silage and when to open extra area in deficit periods.
| Month | UK average (kg DM/ha/day) | ROI average (kg DM/ha/day) |
|---|---|---|
| January | — | 10 |
| February | 5 | 15 |
| March | 20 | 35 |
| April | 50 | 60 |
| May | 70 | 80 |
| June | 65 | 75 |
| July | 55 | 65 |
| August | 45 | 55 |
| September | 40 | 50 |
| October | 25 | 35 |
| November | 10 | 15 |
| December | — | 10 |
Averages based on AHDB and Teagasc grass growth monitoring data. Farm-specific rates vary with soil type, fertiliser use and weather.
Managing Surplus and Deficit
Surplus management
- • Close paddocks above pre-grazing target for silage
- • Top paddocks to maintain quality if grazing is delayed
- • Extend rotation to allow the herd to graze more covers
- • Reduce nitrogen applications until covers come back down
- • Consider buffer grazing — bring forward paddocks that are very heavy
Deficit management
- • Introduce buffer feeding — silage, maize or concentrate at grass
- • Shorten the rotation to reduce recovery time per paddock
- • Reduce the pre-grazing target to stretch available grass
- • Open any closed-for-silage paddocks that have recovered
- • In severe deficits, consider housing earlier or reducing stock
Free tool
AgriOps Grass Wedge Planner
Track paddock covers, view your live grass wedge chart, plan your rotation and get AI-powered advice from Clover — our grazing management assistant. Free to use, no card required.