Establishment
Many establishment principles are similar to cash crops, with several factors influencing how well cover crops get up and away. Discover which ones matter the most to tailor your establishment approach.
Establishment factors:
- Weather
- Soil type*
- Rotation*
- Species/variety
- Sowing time
- Sowing method
- Seed sizes and weights
- Seed rates
- Sowing depths
- Post-sowing care
*For example, establishing a cover crop after late-harvested crops, such as maize, is often only suitable on light/medium soils.
Keep things simple
Because of the diversity of cover crop options and cropping situations, a tailored approach is often needed to minimise variation in establishment. When cover cropping for the first time, keep things simple to minimise the risks associated with disappointing establishment. For example, use lower-cost mixes established with existing on-farm machinery. As your experience builds, devote more time and resource to cover crops to maximise success.
Cultivation and establishment for arable crops (AHDB web pages)
Sowing times
A cover crop can be drilled or broadcast following early-harvested combinable crops in most situations.
- Sow cover crops in good time and exploit favourable conditions (warm, moist soils) to achieve good establishment and early growth
- Most autumn-sown cover crops are sown from August to mid-September, although some are sown outside this window (for example some legumes benefit from an earlier sowing)
- Later-sown cover crops have less time to develop and may not provide adequate soil protection or enhance soil quality
- Late sowing or low soil moisture often results in poor establishment
- Good soil and seedbed conditions are often more critical than the sowing date
In the UK, most cover crops are sown soon after harvest. This provides the warmth and daylength needed for germination and establishment, and maximises growth before temperatures fall. It also improves species choice, such as the inclusion of some C4 species with beneficial traits, such as improved drought tolerance.
In situations where harvest is relatively late (i.e. towards the north), sowing into standing crops before harvest may help to extend cover crop growing periods.
When setting sowing times, time to maturity and flowering should also be considered. Some cover crop species will develop biomass and flower rapidly after sowing (e.g. buckwheat and mustards). Others will take longer (e.g. phacelia and vetches). In general, the former may perform better if sowing is delayed, allowing more rapid accumulation of biomass in a shorter timeframe.
(Image: AHDB)

Sowing method
- Most cover crops can be sown with standard farm equipment (specialist machinery is not usually required)
- Establishment methods should be guided by cover crop choice, equipment and field conditions
- Good residue management is important, with cultivation to assist establishment (when required), to improve seed-to-soil contact and provide a clean seed bed (to minimise competition from weeds)
- Cover crops can be broadcasted or drilled
- For smaller-seeded species on light and medium soils, broadcasting tends to work better
- Where seed-soil contact is poor, such as on heavy clay soils, drilling tends to work better (although this may add costs)
- Good seed-to-soil contact is required for germination and emergence
Seed sizes and weights
The ballistic properties of seeds depend on their size and weight. These need to be considered, especially to avoid striping in the field when broadcasting (for example, heavier seeds tend to broadcast further). It is important to consider both row widths and seed spread.
Machinery selection can help, with some applicators better suited at broadcasting variable seeds. For example, by using an Avadex spreader instead of a standard spinning-disc spreader.
Where an applicator tank has been used to handle herbicides, ensure it is cleaned thoroughly before use.
When mixing cover crop seed in a single hopper, minimise gravitational separation. This is where heavier seed sinks to the bottom of a hopper, especially during transit, even if seeds were initially well mixed. Adding seed mixes to the hopper in smaller, well mixed batches, as opposed to a single bulk load, can help. Where mixtures are used, periodically mix the seed in the drill.
(Image: Yorkshire Agricultural Society)

Seed rates
Seed rates depend on cover crop choice and field conditions.
Recommended standard sowing rates for commercial ‘off the shelf’ straights and mixes are often available online or from seed suppliers.
Consider increasing the rate to compensate for anticipated lower germination and increased seed predation (especially when seeds are surface sown).
If you have a bespoke mix, tailored to your needs, you can use the recommended seed rate for each individual species (sown as straights) and a simple formula to estimate how to reduce the rate for each species in a mix.
Simply divide the individual species sowing rate by the number of species in the mix and use a seed rate calculator.
(Image: AHDB)

Sowing depths
Each cover crop species will have its own optimum sowing depth. A relatively shallow drilling depth is required for most cover crops species.
Sowing-depth information is available in the Cover Crops Guide species selection tool. A value of 0 mm indicates suitability for broadcasting on the soil surface.
On relatively heavy soils, using a shallow (80 mm) tilth-creating tillage when establishing cover crops can reduce problems after cover crop termination in the following spring crop with drill slot opening.
Problems with variable seed depth requirements are most likely to arise with diverse cover crop seed mixes.
Machinery solutions can help to establish mixes where individual seed depth recommendations vary. For example, by broadcasting surface-sown seed from the front of the tractor while drilling seeds at depth at the back, or by using a combi-drill that can place seed at varying depths from independent hoppers.
(Image: Direct Drill, Newcastle University)

Post-sowing care
- Always aim to consolidate seedbeds after sowing
- Rolling enhances seed-to-soil contact and conserves moisture (avoid rolling wet soils)
- In some situations, consider mowing or grazing cover crops
- Inputs depend on the season and cover crop
- Some cover crop species are susceptible to pests and diseases, with slugs particularly significant
- Fertilisers are rarely needed. However, there is little impartial information on starter fertiliser use in cover crops
Only apply nutrients when needed to meet specific objectives, such as biomass generation to build soil organic matter. Always adhere to rules on application type and timing. For specific nutrient management recommendations, consider contacting a specialist seed supplier.
The most commonly used online resources for cover cropping have been reviewed by a team at Newcastle University, with the following recommended for this topic.