Maximise the results from your overseeding operations


15 February 2022

With the price of many products, including grass seed, increasingly dramatically over recent months, it’s even more important than ever to ensure you’re getting the very best results from each and every operation. Redexim UK offer some guidance on the machinery options available when it comes to overseeding, as thoughts turn to getting the course ready for the start of the new season.

Overseeding

The provision of favourable germination and establishment conditions are essential to the success of any overseeding operation. Seeds will differ in terms of the amount of light, moisture and temperature required which will therefore determine both the time and the method in which it should be delivered. Along with considering what mixture to use, the first step to any successful overseeding programme is to consider soil preparation.

Over winter the quality of the rootzone and sward is likely to have deteriorated. Dealing with the effects of any compaction and disease should all be at the top of a turf managers list. Technically grass roots will only grow in the air spaces within the soil so it is vital to create a well aerated and free draining soil structure to give the new seed the best possible start, using machines like the Redexim Verti-Drain. Along with aeration, scarification could also be employed to reduce organic matter levels and optimise moisture and nutrient flow.

With all seeds requiring soil contact, simply broadcasting seed and hoping it will successfully germinate is unlikely to deliver results. Bent grass seed is small and generally requires reasonable soil temperatures to germinate, meaning it is ideal for overseeding in the late summer or early autumn when soil temperatures are relatively high. Because of its size, bent seed only requires rootzone contact – if sown too deep it will exhaust its energy reserves before it reaches the surface. In comparison, chewings and fescue varieties are larger in size and can therefore be sown at a depth of 10-20mm, and successfully germinate at lower temperatures.

The two main options when it comes to the choice of a seeder, is dimple and disc. Dimple seeders utilise one or multiple spiked sarel rollers, creating shallow pots into which the seed can be evenly delivered. Machines such as the Multi-Seeder and Redexim Speed-Seed are ideal for use on fine turf, where drill lines largely need to be avoided. The re-modelled Speed-Seed range features four width options between 1.1m up to 2.3m and creates 990 holes per m² for seed to be delivered and swept into via a rear-mounted brush. The Speed-Seed features a variable seed rate calibration system – which makes ratio adjustments simple and accurate, while a mixing bar and individual seeding elements ensure accurate distribution and less wastage.

Because of its shallow operation, the timing of dimple seeding should be considered to avoid conditions such as strong winds which risk the displacement of any seed remaining on the surface. In situations where high germination rates are a priority, it may be worth considering disc seeders. Giving improved seed to soil contact, disc seeders open up the turf and accurately deposit the seed into the furrow created.

Disc Seeders provide a great alternative when overseeding windows are short or where moisture is lacking, as the seed is down deeper in the soil profile where water reserves and temperatures are more consistent. To optimise coverage, passes with a disc seeder should be conducted in multiple directions. However, and like most greenkeeping operations, timing is essential – too dry and the channels risk opening up, too wet and discs can collect mud and other surface debris, impacting on seed distribution.