What is the fertiliser closed period?

The closed period for spreading chemical fertiliser on grassland typically runs from mid-September to mid-February, depending on the region of the UK. These restrictions are in place to prevent nutrient runoff into waterways during periods when grass growth is low and nutrients are less likely to be absorbed.

While the exact dates vary by region, the principle remains the same — protecting water quality and promoting responsible nutrient management on farms.

Rules in Northern Ireland

In Northern Ireland, the closed period for chemical fertiliser generally runs from mid-September through to the end of January.

There are some exceptions. Fertiliser may be applied to certain crops (other than grass) where a clear crop requirement can be demonstrated.

• No requirement to notify NIEA when applying due to crop need
• Keep detailed records of applications and justification for inspection purposes
• Potash fertiliser can be applied during the closed period if not mixed with nitrogen or phosphorus

NVZ rules in England and Wales

In Nitrate Vulnerable Zones (NVZs) across England and Wales, restrictions apply to manufactured nitrogen fertiliser on grassland between mid-September and mid-January.

NVZs are designated areas where water is at risk from nitrate pollution, and stricter nutrient management rules apply.

• Restrictions apply primarily to nitrogen fertiliser
• Some exemptions exist, such as for specific crops like winter oilseed rape
• Always check current government guidance for full details

NVZ rules in Scotland

In Scotland, the closed period for applying chemical nitrogen fertiliser to grassland typically runs from mid-September to mid-February.

If fertiliser is applied during the closed period under exceptional circumstances, farmers are required to notify their local Scottish Government office shortly after application.

• Written notification may be required for out-of-season applications
• Records should be kept for compliance and inspection purposes

Why accurate record-keeping matters

Keeping detailed fertiliser records is essential for compliance with environmental regulations and farm assurance schemes.

During inspections, farmers may need to show:

• Type and quantity of fertiliser applied
• Application dates
• Field locations
• Justification for any applications during restricted periods

Good records also support better nutrient management decisions and help optimise fertiliser use across the farm.

How Herdwatch can help

Herdwatch simplifies fertiliser and pasture management by giving you the tools to record, track, and plan all field activities in one place.

Fertiliser management

Record fertiliser purchases and applications by field, helping you track usage and manage costs.

Soil fertility insights

Import soil test results and visualise pH, phosphorus, and potassium levels to support data-driven decisions.

Grass measurement tracking

Monitor grass growth, reseeding events, and field performance to improve pasture productivity.

Task and compliance management

Create field jobs, set reminders, and generate reports for inspections and audits.

Farm mapping

Use satellite imagery to map your farm, measure fields, and manage applications more precisely.

All data in one place

Keep all pasture and fertiliser records stored securely and accessible from your phone whenever you need them.

Stay compliant and manage nutrients effectively

Understanding fertiliser closed periods and regional regulations is key to protecting the environment and maintaining compliance on your farm.

With proper planning, accurate record-keeping, and the right tools, farmers can manage nutrient applications efficiently while staying within regulatory limits.