Potting Soil & Compost

Compost is a rich soil amendment you dig into garden beds to feed the soil and improve its structure. Potting mix is a free-draining growing medium designed for pots, containers, and raised beds — it holds moisture without waterlogging, which is critical for healthy roots. You wouldn’t grow directly in compost (it can compact and burn sensitive roots), and you wouldn’t use potting mix alone to improve an existing garden bed. For the best results, use compost to improve the soil and potting mix to fill containers and raised beds. Gammans makes both on-site at our Omokoroa yard.

Compost is best used as a soil amendment — dug into existing garden soil or layered on top or applied as a top-dress — rather than as a standalone growing medium.. For containers, pots, and raised beds where you want to plant directly, use a quality potting mix or a blend like Gammans Superior Garden Mix, which combines potting mix and compost for the best of both.

Most garden beds benefit from compost two to three times a year — the best times are late winter before spring planting, mid-summer to replenish nutrients during the growing season, and in autumn to feed the soil before winter. For heavy-cropping vegetable beds, a light top-dressing every 6–8 weeks through peak season will keep plants producing well. The key is not to wait until your plants show signs of struggle — regular small applications outperform one large annual dump.

As a general guide, apply 5–10cm of compost when preparing a new garden bed, worked into the top 20cm of soil. For an established bed being top-dressed, 3–5cm is sufficient. To calculate volume: multiply your bed length x width x depth (all in metres) to get cubic metres. For example, a 3m x 2m bed with a 7cm top-dress = 3 x 2 x 0.07 = 0.42m³. Not sure how much to order? Check out this article on How to Estimate Landscape Supplies or drop into the Gammans yard or call us — we help with this calculation every day.

For vegetable gardens, you want a garden veggie mix that drains freely, retains moisture between waterings, and provides a good supply of nutrients. Look for a peat-based mix enriched with compost and quality fertilisers — this gives your vegetables both structure and nutrition. Gammans Premium Potting Mix is made on-site using peat from our own Hauraki mine, making it one of the few NZ potting mixes where the producer controls the full supply chain. For raised beds, our Superior Garden Mix — a pre-blended combination of potting mix and compost — gives even better results.

Most home gardeners will be well served by Gammans’ standard Premium Potting Mix or Superior Garden Mix. Custom blending is for growers with specific requirements — commercial nurseries, orchardists, and specialist crop growers who need consistent batch-to-batch performance with a precise nutrient profile, drainage ratio, or pH level. Gammans offers over 200 custom blend options using Hauraki peat or composted bark fines as a base, and we work with nurseries and commercial growers across NZ to formulate mixes for their exact crop and growing conditions. Minimum 3-day lead time. Call us to discuss.

Orchard compost is a specialist bulk compost formulated for commercial growing conditions — typically with a higher carbon-to-nitrogen ratio and a formulation designed to support the intensive demands of orchard soils. Garden compost is formulated for home garden applications and smaller quantities. Gammans Orchard Compost is used by Bay of Plenty orchardists — kiwifruit, avocado, citrus, and pip fruit growers — and is available by the truckload with Bay-wide delivery. If you’re a commercial orchardist, we can also work with you to develop a custom compost or potting mix for your specific crop.

Yes. Gammans delivers Bay-wide by truck with a minimum order of 2m³. We cover Tauranga, Mount Maunganui, Papamoa, Bethlehem, Te Puna, Omokoroa, Katikati, and the broader Western Bay of Plenty region. For wholesale and nursery orders, we can also deliver nationwide in sling bags. If you’d prefer to pick up, our free courtesy trailers (single and double axle) are available for up to 2 hours when you purchase at the yard. Call 027 548 1278 to arrange delivery or discuss your requirements.