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Oversowing sub-clover into existing pastures: A practical guide

May 13 2026

If your sub-clover content has declined, oversowing into an existing pasture can be a practical, low-cost way to restore productivity without the expense and disruption of a full renovation.

With the right preparation, sowing method and grazing management, sub-clover can be introduced successfully into perennial pastures and begin improving feed quality, nitrogen fixation and overall pasture performance from the first year.

Start with the pre-sowing checks

Pre‑sowing checks are carried out up to a year before oversowing. They’re essential. If soil conditions aren’t right, pests aren’t controlled, or weeds and competitive species aren’t reduced, your chances of success drop dramatically.

Check soil fertility early

Before sowing, conduct a soil test on the paddock to ensure fertility levels are sufficient. Certain treatments, such as lime applications, may need to be completed ahead of sowing.

Manage pests before they become a problem

In the year prior, manage red‑legged earth mites (RLEM) using the TimeRite® strategic control program. If there is a lot of dry residue remaining after grazing, as a precaution, apply slug bait post-sowing.

Set up the paddock for competition control and grazing

Ideally, the pasture should be grazed short before sowing. This improves herbicide contact and helps achieve good seed‑to‑soil contact.

Paddocks need to be set up for grazing to manage them effectively before and after sowing.

Good fencing and paddock subdivision are also important so grazing pressure can be matched to land class, helping avoid overgrazing flats and under grazing hill country.

If grazing pressure alone is not enough to reduce phalaris competition, apply paraquat just before sowing to suppress the phalaris temporarily and remove newly germinated weeds.

Reduce weed pressure before sowing

A critical step is controlling problem weeds the year before sowing. This reduces competition.

Depending on your weed burden, this might involve spray‑topping or winter cleaning for annual grasses, or spray‑grazing for broadleaf weeds such as capeweed.

Choose the right variety

Make sure to choose cultivars suited to your soil type and with maturity times that allow flowering and seed set before the growing season finishes.

The flowering time is critical. It influences persistence, seed production, and total feed grown.

Some may also choose to sow two cultivars with flowering times 2–3 weeks apart to buffer against seasonal variation.

Most importantly, always sow certified seed. This ensures you avoid introducing oestrogenic or unproductive clovers or unwanted weed seeds.

Pay attention to inoculation

Most purchased sub‑clover seed comes pre‑coated, including inoculation with live rhizobia bacteria that enable nitrogen fixation.

For best results, sow seed within six weeks of inoculation and store it in a cool place. If you plan to use leftover seed, re‑inoculate it just before sowing.

Use the right sowing equipment

Direct drilling is the preferred method of oversowing. This places the seed directly into the soil and covers it with 5–10 mm of loose soil, helping protect seedlings from drying out.

For best results, use a drill with row spacing of 20 cm or less and keep the speed below 6 km/hr so seed placement remains accurate.

Broadcasting or aerial seeding should be reserved for steep or non-trafficable areas. This method has a lower success rate due to the lack of seed-to-soil contact. After spreading the seed, run livestock across the paddock to help tread the seed into the soil.

If you don’t have the correct equipment, make sure to contact a sowing contractor early in the season.

Get timing and sowing technique right

Annual clovers must be sown in autumn as they need exposure to a certain number of daylight hours to enable seed production. Sowing in spring or even late winter simply won’t work.

The ideal time to sow is at the autumn break, once the soil is damp enough to produce a good tilth. Moist conditions support even germination and help rhizobia survive on inoculated seed.

Avoid sowing when prolonged heavy rain is forecast, such as 50 mm over a few days. Seeds need oxygen around them to germinate, and extended waterlogging can cause them to rot.

Apply starter fertiliser carefully

Starter fertiliser can be drilled with seed with rates of 10 to 20 kg/ha of nitrogen, 15 to 30 kg/ha of phosphorus, and at least 15 kg/ha of sulphur.

Avoid placing potassium in the drill row with seed – it can burn the emerging seedlings. Apply potassium separately, either just before or just after sowing.

Monitor establishment

Sub‑clover typically emerges within a week, even in cooler soils, provided moisture is adequate. Check for establishment every few days, looking for two healthy cotyledons.

If you see silvery leaves – this usually indicates red‑legged earth mite damage.

If you’re seeing missing cotyledons – slugs may be your problem.

Any sign of pest damage should trigger immediate control.

Check whether sowing has worked

6 to 8 weeks after sowing we can assess our success.

Using the Pasture Paramedic 40 cm ruler, count the number of seedlings along the drill row in six different locations and average the results.

For example, if clover was sown at 15 kg/ha, then 7 seedlings per 40 cm represents around 50% establishment, which is an excellent outcome.

Use grazing to protect young clover

Sub‑clover germinates and grows quickly early on—it’s an important survival trait. But once perennial grasses take off, their leaf area expands rapidly and can shade out young clover.

This makes grazing management critical.

Begin grazing once seedlings have produced three true leaves.
Keep the pasture short, ideally no more than 5 cm, until the first flowers appear.
Reduce grazing pressure once flowering begins so seed set can be maximised.
In the first year, avoid heavy grazing or cutting for fodder because this removes flowers and reduces seedbank development.

Building a strong seedbank early provides insurance against poor germination or poor seed set in future years.

Conclusion

Oversowing sub-clover into an existing perennial pasture is one of the lower-risk pasture improvement options available when preparation and management are done well. Success depends on reducing weed and pasture competition at sowing, maintaining adequate fertiliser, and grazing strategically through winter and early spring to favour clover establishment and seed set.

For producers looking to rebuild clover content without full pasture renovation, oversowing can turn an average paddock into a more productive one.

Use the ‘Oversowing sub-clover checklist’ (pictured below) to plan your sowing for success!