The real decision here isn’t between three similar-looking bags. It’s whether you want to add live biology to the sward, or feed the biology that’s already there. Settle that first, then match the granule size to how tight you cut.

Live bacteria and fungi, or an amino acid feed?

Phoenix Pro-Bacter is the true biological product in this range. Alongside a 5-5-20 + 1% MgO organic-based feed, it carries live Bacillus bacteria and Trichoderma fungi. Once it’s down, the bacteria get to work breaking down thatch and dead moss in the turf, converting it into nutrients the grass can use, with no raking and none of the black staining you get from an iron-based mosskiller. Worth knowing if you’re treating turf near paths or drives. It’s rated for lawns cut at 10mm or above, applied March to late October.

Onyx Regular and Onyx Mini take a different approach. Both are organic granular products built on amino acids rather than added microbial strains: 30% amino acids in Onyx Regular, 11% in Onyx Mini, alongside nitrogen, potassium and trace elements. The idea is that the amino and humic acids feed the microbes already living in your soil and help form nutrient complexes that support soil structure, rather than introducing new bacteria the way Pro-Bacter does. If the job is turf recovering from mowing, weather stress or a recent chemical treatment, that’s the mechanism doing the work, not a live inoculant.

What turf height are you cutting to?

This is where Onyx Regular and Onyx Mini part company, and it isn’t just packaging. Onyx Regular’s 2-3mm granule and 13-1-2 analysis suit lawns, parks and general turf kept above 10mm. Onyx Mini’s 1-2mm granule and 10-0-4 analysis are built for greens and other close-cut turf down to 6mm: the finer granule spreads evenly and doesn’t sit awkwardly on top of a tight sward. The lower nitrogen in Onyx Mini fits that job too, there’s less top growth to manage on a green than on a stretch of lawn. Both apply at 350-500kg/Ha, year round, with around six weeks of feed per application.

Which product for which job

General lawn troubled by thatch or moss, and you want to skip the raking and the staining: Phoenix Pro-Bacter. Everyday organic turf feed for lawns, parks or renovation work above 10mm: Onyx Regular. Greens or any turf mown to 6mm or below: Onyx Mini.

If you’re not sure whether thatch or moss is the problem on your lawn, work that out before you buy. Pro-Bacter and the Onyx range solve different problems, and the wrong pick just means an extra bag next season. Call the Phoenix Amenity team if you want help matching a product to your turf and cutting height.

Frequently asked questions

Will Pro-Bacter stain paths and patios like an iron-based mosskiller?

No. Pro-Bacter contains no sulphate of iron, the ingredient responsible for the black staining you get from typical iron-based mosskillers, so it will not stain hard surfaces.

What is the real difference between Onyx Regular and Onyx Mini?

Mainly granule size and where you can use it. Onyx Regular's 2-3mm granule suits lawns, parks and general turf above 10mm, while Onyx Mini's 1-2mm granule is built for greens and turf cut to 6mm or below. The analysis differs too: 13-1-2 plus 30% amino acids for Regular against 10-0-4 plus 11% amino acids for Mini, so Regular carries more nitrogen.

Can I use Pro-Bacter and an Onyx product on the same lawn?

They do different jobs, thatch and moss breakdown against an ongoing amino-acid feed, so nothing in either product's specification rules out using both across a season. If you are planning a full feeding programme, it is worth talking it through with the Phoenix Amenity team so timing and rates line up for your site.