Gardening Supplies

Material Composition Assumptions

The “gardening supplies” category spans an exceptionally wide range of products — from plastic plant pots and hand tools to growing media, garden hoses, and watering cans. The CCI score reflects a category-weighted average across common product types, normalised per kilogram of product purchased. The key sub-categories contributing to the average are:

Plastic containers, pots, and trays (~30–40% of category sales by weight):

• Polypropylene (PP): The dominant material for plant pots, seedling trays, and watering cans. Emission factor ~2.0–2.5 kgCO2e/kg resin; ~2.5–3.0 kgCO2e/kg for injection-moulded or blow-moulded finished product. A standard 5-litre PP plant pot weighs approximately 200–400 g.
• High-Density Polyethylene (HDPE): Used for garden planters, storage bins, and some watering equipment. Emission factor ~1.9–2.2 kgCO2e/kg resin.
• Recycled plastics: Post-consumer recycled PP or HDPE increasingly used in premium plant pots and garden planters; emission factor approximately 0.8–1.2 kgCO2e/kg for recycled resin. GRS (Global Recycled Standard) certification available.
• Terracotta and ceramic: Traditional plant pot materials; emission factor ~0.8–1.5 kgCO2e/kg for kiln-fired terracotta, driven by kiln energy and clay processing. Heavier than plastic alternatives, so shipping emissions are higher.

Growing media (compost, potting mix) (~25–35% of category by weight):

• Peat-based growing media: The dominant potting compost formulation globally (though declining). Peat extraction from sphagnum bogs releases long-sequestered carbon (estimated 10–30 kgCO2e/m³ of peat extracted, or approximately 0.5–2.0 kgCO2e/kg of growing media at 30–50% peat content). Beyond extraction emissions, ongoing drainage of peat bogs for extraction continues to release CO2 at ~5–20 tCO2e/ha/yr.
• Peat-free alternatives: Composted bark, wood fibre, coir (coconut husk fibre), green compost, and biochar. Emission factors typically lower than peat (~0.1–0.5 kgCO2e/kg) but supply chains and quality consistency vary. Coir is a by-product of coconut processing shipped from Sri Lanka, India, and the Philippines — transport emissions are non-trivial.
• Soil conditioners and mulches: Composted green waste, composted manure, woodchip mulch. Typically low emission factors (~0.05–0.3 kgCO2e/kg) and may carry biogenic carbon storage credits if from sustainably managed sources.

Hand tools (~15–25% of category by weight):

• Steel garden tools (spades, forks, trowels, rakes): Predominantly carbon steel or stainless steel blades with wood or polypropylene handles. Steel emission factor ~2.0–3.0 kgCO2e/kg for finished forged or stamped tool head. Wooden handles (ash, hardwood): ~0.3–0.6 kgCO2e/kg.
• Aluminium tools (lightweight trowels, rakes): Emission factor ~8–12 kgCO2e/kg for primary aluminium; ~1.5–3.0 kgCO2e/kg for recycled aluminium. High per-kg intensity but very low mass.
• Zinc-plated wire and hardware: Used in garden stakes, plant supports, and wire structures. Galvanised steel wire ~2.5–3.5 kgCO2e/kg.

Hoses and irrigation (~5–10% of category by weight):

• PVC garden hose: Typical 15m hose weighs ~1.5–2.5 kg. PVC compound ~1.9–2.5 kgCO2e/kg; full hose including fittings approximately 2.0–3.0 kgCO2e/unit.
• Drip irrigation systems: Polyethylene tubing and fittings; lower per-m² water use and moderate embodied carbon.

Manufacturing Geography

Gardening supply manufacturing is distributed across three primary geographies, with significant divergence by product type:

• China: Dominant supplier of plastic garden products (pots, planters, tools, hoses) for global export markets. Grid intensity ~565 gCO2e/kWh. China produces the majority of polypropylene granules used in gardening products and is a significant producer of steel hand tools. Long supply chains add 0.1–0.3 kgCO2e/kg for ocean freight to North American and European markets.
• EU: Significant production of growing media (compost, peat — though declining with regulatory pressure in the UK and EU), ceramic pots, and premium hand tools (Fiskars in Finland, Wilkinson Sword/Spear & Jackson in UK). Grid intensity ~300 gCO2e/kWh. European growing media production benefits from regional agricultural by-product supply chains.
• USA: Domestic production of growing media (Sun Gro Horticulture, Miracle-Gro/Scotts) and some premium garden tools. Grid intensity ~390 gCO2e/kWh. Growing media is heavy and regionally sourced due to transport costs.

The CCI score uses a blended profile reflecting the mix of imported plastic products (China-dominant) and regionally sourced growing media, weighted by approximate category sales volume.

Regional Variation

Region	Grid Intensity	Estimated Score Adjustment
China (plastic products)	~565 gCO2e/kWh	Baseline (higher grid, dominant for plastics)
EU production	~300 gCO2e/kWh	-10% on Scope 2 for manufactured items
USA domestic production	~390 gCO2e/kWh	-5% on Scope 2 for manufactured items
Peat-free growing media (EU)	—	-0.3 to -0.8 kgCO2e/kg vs. peat-based
Recycled plastic products	—	-0.8 to -1.2 kgCO2e/kg vs. virgin plastic

Note: The dominant emission driver in this category is Scope 3 — upstream material content (peat, plastics, fertiliser inputs) — which accounts for approximately 75% of the total footprint. Scope 2 (manufacturing electricity) is a relatively minor contributor at ~20%. The largest single emission reduction lever is peat substitution in growing media, which eliminates the significant peat extraction carbon release.

Provenance Override Guidance

A supplier or manufacturer may override the default CCI score by submitting:

1. Product-level lifecycle assessment (LCA) per ISO 14040/14044 or product carbon footprint (PCF) per ISO 14067. Given the category’s diversity, SKU-specific data normalised per kg of product is the preferred override format.
2. Growing media peat content declaration — mass fraction of peat and peat-free alternatives, with peat extraction site location and bog status (protected, degraded, or actively restored). Peat-free certification (e.g., Royal Horticultural Society Endorsed Peat Free, UK) is accepted.
3. Recycled plastic content verification — GRS or equivalent certification for post-consumer recycled PP or HDPE content, with chain-of-custody documentation and supplier emission factor.
4. Fertiliser nutrient content and emission factor — for soil amendment products containing synthetic nitrogen, verified emission factor from the nitrogen fertiliser producer (ideally from a plant with N2O abatement technology).
5. Steel and tool supply chain data — mill-level emission factor for steel components, including recycled scrap content percentage. Electric arc furnace (EAF) steel with high scrap content carries ~0.5–1.0 kgCO2e/kg vs. blast furnace steel at ~1.8–2.2 kgCO2e/kg.

Methodology Notes

• CCI score of 2.0 kgCO2e/kg represents a category-average estimate for the gardening supplies sector, blending plastic pots (~2.5 kgCO2e/kg), peat-containing growing media (~1.5 kgCO2e/kg), and steel hand tools (~2.5 kgCO2e/kg) in approximate proportion to market sales mix. Individual product scores vary from approximately 0.3 kgCO2e/kg (composted bark mulch, no peat) to over 5.0 kgCO2e/kg (virgin aluminium tools, peat-heavy growing media with synthetic fertiliser amendments).
• Scope breakdown: Scope 3 dominates at ~75% (1.5 kgCO2e/kg), driven by plastic resin production (~38%), peat extraction (~28%), and fertiliser inputs (~18%). Scope 2 (manufacturing and assembly electricity) accounts for ~20% (0.4 kgCO2e/kg). Scope 1 (direct process heat, kiln energy for ceramics) accounts for ~5% (0.1 kgCO2e/kg).
• Functional unit: One kilogram of gardening supply product (weighted category average), cradle-to-gate. The per-kg normalisation is appropriate for category comparison but less useful for individual product decision-making, where per-unit or per-use comparisons are more meaningful.
• Low confidence rating reflects very high within-category variability (plastic pots vs. compost vs. hand tools vs. irrigation equipment carry fundamentally different emission profiles), limited published LCA data for specific gardening supply SKUs, and complex peat carbon accounting with high uncertainty in peat bog emission rates.
• Peat policy context: The UK government and EU are progressively restricting peat use in amateur horticulture. England targeted a ban on retail peat sales by 2024 (subsequently delayed); professional horticulture phase-out planned by 2026. This policy environment is rapidly shifting the growing media emission profile. Products marketed after 2025 will increasingly be peat-free, which would reduce the category average to approximately 1.0–1.5 kgCO2e/kg.
• Durability and multi-season use: Hand tools and durable plastic pots are multi-season products. A steel spade with a 20-year service life has a per-season carbon cost of ~0.1–0.15 kgCO2e — negligible relative to growing media or fertiliser purchases made annually.