UK Cover Crops and Catch Crops 2026

Last updated: May 2026. This guide covers cover crops and catch crops on a UK working farm in 2026: the SFI actions that pay for them, species selection, the salad/veg vs combinable arable economics, drilling and termination, residue management, and the mixes that work on dry Suffolk ground vs western wetter conditions. It is general information from a working salad and arable holding, not bespoke agronomy. See the planning checklist at the end for what to do this season.

The phacelia in the cover-crop mix on the wheat stubble block came up unevenly last September, and the agronomist and I stood on the headland in mid-October arguing about whether to roll it before the first frost or leave it standing. Twenty-one summers in salad and veg in Suffolk, two years with arable folded back into the rotation, and I’d have told you cover cropping was the simple end of the regen story. It isn’t. The species pick, the drill date, the termination window and the residue you leave behind are four decisions, and any one of them can swing the margin on the following crop by more than the seed mix cost in the first place.

This guide is the conversation with our agronomist since the move into the arable rotation, with the SFI 2026 paperwork on the table. The veg side has been a different argument for the best part of two decades. The arable side is where the cover-crop economics actually stack up.

Where UK cover crops sit in 2026

Cover crops have moved from a regen-curiosity practice to a mainstream arable action in about five years. The SFI offer is the single biggest driver of uptake, with CSAM2 (multi-species winter cover crop) paying £129/ha across the 2026 agreement window.[1] The AHDB Cover Crops Field Lab, run with the farmer-led Innovative Farmers network from 2018 onward, produced the working UK trial dataset most agronomists now quote, and NIAB TAG has been running its own cover-crop trial series since the mid-2010s.[2][3]

The point most working farmers miss is that cover crops are not a single intervention. They are a category. The four working purposes are nitrogen capture on a residual soil-N pool, nitrogen fixation via a legume for the following crop, structural and biological work via deep roots, and weed suppression. A species mix that does one of these well often does the others badly. A frost-killed mustard is brilliant on N-capture and weed suppression and fixes nothing. A pure vetch fixes N and does little else. Picking a mix without picking the purpose is the most expensive mistake on the cover-crop spend.

The policy backdrop is stable for 2026. The IPM-side cover-crop actions are funded, the soil-side action menu has narrowed since the original ELM ambition but the cover-crop action survived, and the Defra Indicators of Soil Health for England 2026 release flagged cover cropping as a working improvement lever inside the indicator framework.[4]

SFI 2026 actions that pay for cover crops

The headline action is CSAM2: multi-species winter cover crop, paying £129/ha for an established cover from at least two species in two or more eligible plant families, in place across December, January and February each agreement year.[1] An oats-and-rye-only mix doesn’t qualify; an oats-and-vetch mix does. The cover has to be established by the end of October on most agreements.

CIPM3, companion crop on arable and horticultural crops, pays £55/ha for a low-rate companion species (typically a legume) drilled with the cash crop and not as a stand-alone cover.[5] On a winter oilseed rape that often means berseem clover or vetch broadcast with the rape at drilling.

CNUM3, legume fallow, sits at £532/ha for 2026 (down from £593) and is the 12-month rotational fallow rather than a winter cover.[6] The rate cut is steep enough that some holdings that ran it in 2024-25 are not renewing.

The cover-crop action survived the 2026 rate review largely intact, which is one of the few positives in the new offer. The structural soil management plan action has gone, the herbal-ley rate has been cut by 41%, and the species-rich grassland action has migrated to Countryside Stewardship Higher Tier.[6]

What I’d actually do: read the CSAM2 specification twice before you map fields to it. The two-family eligibility and the December-January-February presence window catch farmers out every year.

Species selection: what each one actually does

The working species list for UK cover cropping is shorter than the seed-catalogue noise suggests. Six species do most of the work.

Mustard (white or brown) is the standby for fast establishment, weed suppression and biomass. It fixes nothing. It frost-kills cleanly in most UK winters from December onward. The trap is club-root: in a brassica rotation, including oilseed rape, mustard adds to the disease load and the agronomist will push back hard.

Vetch (common or hairy) is the working legume for biological N fixation. Hairy vetch tolerates a Suffolk frost better than common, and the autumn establishment is more reliable. Working numbers from NIAB trials sit at 30 to 60 kg N/ha across a winter cover, with the higher figures only on well-established stands on the right soil.[3] As a stand-alone, vetch is poor on biomass and weed suppression. In a mix with oats or rye, both jobs improve.

Phacelia is the cosmetic species in most cover-crop catalogues and the practical one for soil biology. It has no plant-family overlap with arable or vegetable cash crops, so it slots in anywhere in the rotation. It does decent biomass, some weed suppression, and the deep fibrous root system is the genuine biological story. It does not fix N.

Clover (crimson for cover, red for longer rotations) is the slower-establishing legume. Crimson clover does a usable autumn N fix on a longer-established cover and is relatively cheap. Red clover is closer to a green manure than a cover crop.

Rye (cereal rye, not ryegrass) is the heavy-biomass option for structural work. The deep root mass is the highest of any common cover-crop species, and the residue load after a March termination is the practical question for the following drill. Rye is the right pick where the cash crop is a spring break and the structural job is the priority. It is not the right pick where you’re spring-drilling with a tine drill on a wet year.

Oats (typically black or grey oat in a cover mix) are the working alternative to rye where the biomass needs to be lower for following-crop establishment. Black oats frost-kill in most UK winters from late December, which gives easier termination than rye but less residue. The standard CSAM2 base mix on our blocks is black oats and vetch with a phacelia top-up.

Oilseed radish (Tillage radish in the trade names) is the supporting species for deep tap-root structural work and N capture, and buckwheat is the summer catch-crop option for fast biomass and P mobilisation. The mix design is two or three species doing the working jobs, with one or two supporting species adding incremental structure or biology.

Mixes for Suffolk dry ground vs western wetter conditions

This is the bit the national trial data doesn’t tell you, and the bit your agronomist actually earns the fee on.

On our Suffolk blocks the autumn moisture is the limiting factor for cover-crop establishment. A normal year gives a drying September and a tight window for direct-drilling a cover into a wheat stubble. Establishment failures in our area are mostly moisture failures, not species failures. The working mix is black oats and vetch with a low rate of phacelia (around 50 kg/ha total seed, scaled down from the textbook), drilled by mid-September if possible into a stubble that hasn’t lost all its moisture. Mustard goes in earlier on lighter blocks where the moisture is gone by drilling.

On wetter western ground (Worcestershire, Shropshire, the wetter Welsh borders, the heavier parts of Devon and Cornwall) the picture inverts. Moisture is rarely the limiting factor. The constraint is termination on a soft soil in March, and the residue load on a direct-drilled spring crop. Rye-heavy mixes work in wetter conditions where the biomass and structural job is the priority. Frost-kill is less reliable across a milder western winter, which means roller-crimping or glyphosate-and-cultivator combinations are the working answer.

What I’d actually do on a dry Suffolk block: oats-vetch-phacelia at modest seed rate, drilled by mid-September, frost-kill expected, spring drill in March. On a wetter western block: rye-vetch-radish at higher seed rate, drilled into early October, roller-crimped or glyphosated on a March window. Don’t run the same mix across both.

Cover crops on the arable break vs cover crops on salad and veg

The economics diverge sharply between these two halves of a working rotation.

On the arable break, NIAB TAG trial data shows yield responses on a following spring barley or spring bean crop of 0.25 to 0.5 t/ha across a multi-year average, with a margin improvement of around £80/ha once nitrogen savings and seed costs are netted out.[3] Seed costs of £20 to £50/ha are standard for the CSAM2-compliant mixes. The CSAM2 payment of £129/ha sits on top of that, which gets a typical cover-crop block to a positive margin of £100 to £180/ha in a normal year, before any structural benefit on the following two or three crops.

In the salad and veg rotation the maths is worse. A cover crop on a salad block is doing structural work, not nitrogen-cycling work, because the rotation already runs on heavy organic-matter inputs from the muck programme. The window between a September salad lift and the next bed prep in February or March is often too short for a genuine establishment. On polythene-covered blocks the cover-crop window is essentially closed. The CSAM2 December-January-February presence requirement collides with the bed-prep calendar for early spring crops.

Where cover crops have paid for us is on the arable break-crop fields, not the veg blocks. A multi-species winter cover into a wheat stubble gives genuine structural and biological gains by spring drilling, and the CSAM2 payment makes the maths comfortable. On the salad blocks the agronomic answer is residue management and bed-rest. The salad grower who tries to replicate the arable Field Lab result on a salad bed will lose money on the year.

Catch crops between salad and veg

Catch cropping is the salad and veg version of the cover-crop story, and the answer most of the SFI literature ignores. A catch crop is a short-duration intercrop between two cash crops, drilled into a window of four to twelve weeks. The purpose is biomass and N capture, not nitrogen fixation.

The working species on our holding are mustard, buckwheat and a quick-establishing oat or rye for the short window between a July salad lift and a September brassica drill. Buckwheat is the underrated pick: 60 days to a usable biomass on a warm summer block, P mobilisation that has measurable effects on the following crop, and a clean kill before flowering by mowing or shallow cultivator. Mustard does similar biomass in similar time, with the club-root caveat for any brassica rotation.

Catch cropping doesn’t get an SFI payment in 2026 because the duration is too short to qualify under CSAM2, and there isn’t a parallel summer-cover action funded in the current offer. The cost-benefit case stands on its own: weed suppression, soil cover across the warmest months, organic-matter contribution, and the catch on residual nitrogen that would otherwise leach in a wet autumn. Seed cost is £30 to £60/ha, establishment cost is modest, and termination is a single shallow cultivator pass.

Looking back, I’d say the catch-crop slot is the most under-used intervention on a working salad and veg holding.

Drilling, termination and residue management

The four operational decisions on a cover crop are drill date, seed rate, termination method and residue handling. Each is where most holdings make their expensive mistakes.

Drill date is the single biggest variable. On a Suffolk autumn the cover-crop drill should be in by mid-September if possible, with an October drill the practical fallback and anything in November close to a write-off. The working evidence from the Field Lab and the NIAB trials is that biomass at termination scales almost linearly with the days from drilling to first frost, and an October-drilled cover delivers around half the biomass of a mid-September drill on a comparable block.[2][3] Seed rate is a second-order question; drill date does most of the work.

Termination has three working methods. Frost-kill (mustard, black oats, hairy vetch in a hard winter) is the cheapest and the easiest. Mechanical termination by roller-crimping is the regenerative-agriculture answer on a heavy biomass cover, with the kit becoming more available and the timing window narrow (the cover has to be in flower or early seed). Glyphosate-and-cultivator combinations remain the working method on most holdings where the termination window collides with the drill date for the spring crop, and the regulatory position on glyphosate in 2026 is unchanged from 2025: approved in GB, with the EU re-authorisation through 2033 reflected in HSE guidance.[7]

Residue management is the most under-thought decision. A high-biomass rye-vetch cover terminated in March with a roller-crimper leaves a residue mat that a tine drill struggles to penetrate on a soft soil. A frost-killed mustard leaves a thin residue that establishes a spring drill cleanly. The pick depends on the drill and the soil, not on the cover crop in isolation.

AHDB and NIAB trial data: what to believe

The trial literature on UK cover cropping is better than it was five years ago, and still patchier than the press releases suggest. The 2025 scoping review of UK regenerative practice flagged cover cropping as one of the few practices where the empirical evidence base for UK conditions is reaching usable thresholds, with the caveat that the long-term rotational data is still thin.[8]

The headline working numbers: a 0.25 to 0.5 t/ha yield response on the following spring crop; a 30 to 60 kg N/ha contribution from a legume-component mix; a margin of £80/ha excluding SFI, or £150 to £200/ha with CSAM2 included; a structural improvement that takes three to five seasons to show up reliably in a VESS score or earthworm count.[2][3]

What the trial data doesn’t tell you is the variance. The Field Lab year-to-year variation on the same block is wider than the mean effect, which means a single-year trial result on a single block is genuinely unreliable for working farm decisions.[8]

If I’m honest, the working position is that the long-term effect is real, the in-year effect is variable, and a cover-crop programme run for one year and abandoned because the spring barley yield was disappointing is worse than no programme at all. The decision is for a rotation, not a season.

A 2026 planning checklist

For working farms running into the 2026 cover-cropping season, the housekeeping comes down to an autumn afternoon at the kitchen table.

Pick the purpose first. If the purpose is nitrogen fixation, the mix needs a substantial legume component. For structural work on the arable break, the mix is rye-heavy on western ground or oats-and-vetch on dry Suffolk ground. For summer catch cropping between salad and veg, the mix is mustard or buckwheat.

Map the CSAM2 specification against the arable break-crop fields, not the veg blocks. Cost the seed at NIAB-comparable rates and the establishment at the actual fuel and time cost on your holding. Build the gross margin including the £129/ha SFI payment and the realistic yield response on the following crop.

Drill by mid-September if at all possible. The biomass-against-drill-date curve is the most evidence-backed number in the cover-crop literature, and a late-September or October drill is half the cover.

Pick the termination method with the drill and the soil in mind. A frost-killed light residue suits a tine drill on a structured soil. A roller-crimped heavy residue suits a disc drill in dry conditions. A glyphosate-and-cultivator combination is the working compromise where the termination window is tight.

For the soil-side context, see UK Soil Health 2026. For the broader SFI picture, see SFI 2026 actions. For the crop-protection backdrop on glyphosate, see UK Crop Protection 2026. The wider set of long-form pieces sits in the Knowledge Hub.