Substrates for those who grow outdoor plants
Formulas for ornamental nurseries, open ground, landscape contractors and small fruits. Medium-coarse granulometry, high wood fiber content and structural materials for long outdoor cycles in containers or open ground.
What is a substrate for outdoor plants
A substrate for outdoor plants is a medium-coarse granulometry formula, with high wood fiber content and mineral structural materials (perlite, pumice, volcanic Lapillus), designed for long cycles (12–36 months) in outdoor containers or open ground. The air-to-water balance is optimised to withstand heavy rainfall without compacting and to retain water reserves during dry periods.
Four criteria for outdoor ornamental nurseries
What differs between an indoor repotting formula and an outdoor container formula.
Medium-coarse granulometry
Predominantly 0–25 mm fraction, with a coarse share for post-rain drainage. The wider granulometry reduces compaction from repeated wetting and maintains aeration around the roots.
Wood fiber + pumice
Thermo-sanitised wood fiber stabilises the structure over time (18+ month cycles), pumice adds persistent mineral porosity. The combination resists the decomposition that affects peat-only formulas over long cycles.
pH adapted to outdoor crops
Outdoor acid-loving plants (azaleas, blueberries, outdoor camellias) require formulas with high buffering capacity to resist pH rise from rainfall. General ornamentals fall within a higher pH range.
Water retention capacity during dry periods
Summer outdoor cycles alternate between high transpiration and intermittent irrigation. The formula must hold water reserves without saturating. The balance is achieved with block-cut blonde peat and wood fiber of selected granulometry.
Arber substrates for outdoor plants
Forest X for long outdoor cycles, plus specific formulas for acid-loving plants, container fruit and cuttings. Each formula dedicated to its crop.
Forest X
Acid
Camelia
Blueberry K1 + Perlite
Acni V18
Mus-RK1
Taleas S5
Outdoor plants comparison table
| SKU | Structure | pH | EC mS/cm | Recommended pot |
|---|---|---|---|---|
| Forest X | Coarse | 5-6 | 1.1-1.4 mS/cm | from 14 |
| Acid | Medium-coarse | 3-4.5 | 2-3 mS/cm | from 14 |
| Camelia | Medium-coarse | 5.2-5.8 | 0.4-0.6 mS/cm | from 14 |
| Blueberry K1 + Perlite | Medium-coarse | 3.5-4.5 | 0.1-0.3 mS/cm | from 16 |
| Acni V18 | Medium-coarse | 5-6 | 1.1-1.4 mS/cm | 14-18 |
| Mus-RK1 | Coarse | 7.3-7.5 | <0.5 mS/cm | n/a |
| Taleas S5 | Medium-fine | 5.2-6 | 0.4-0.6 mS/cm | n/a |
Indicative data from sample, referenced to the formulation batch. Declared tolerances are listed in the technical data sheet for each SKU.
What outdoor nurseries and landscape contractors ask
Can I get a custom formula to my specification?
Yes. For volumes compatible with nursery or site requirements, we develop personalised formulas based on the crop, container, irrigation schedule and location. The first pilot batch typically arrives within 3–4 weeks.
How long does delivery take across Italy?
We deliver across Italy. Transport is included to the gate, including Big Bag delivery for landscape contractors. Typical lead times are 3–7 working days.
Do you hold supply chain certifications?
Yes. The German section of the supply chain is HORTICERT certified. Selected professional raw materials are RAL certified by the Gütegemeinschaft Substrate für Pflanzen. Organic lines use FiBL-certified raw materials.
How does a quote or sample request work?
The “Request a quote” form collects your crop, estimated annual volumes and region. The request goes to your local sales agent, who prepares the sample and technical data sheet.
How does agronomic support work?
Your local sales agent assists with formula selection, outdoor pilot trials and analysis of any mid-cycle issues. For complex cases, the agent involves the in-house formulation team.
What is the difference between Forest X and Forest FR Type 3?
Forest X is the long-cycle substrate for outdoor containers of 5–25 L (18-month cycles). Forest FR Type 3 has a higher wood fiber content and coarser granulometry: it is designed for ornamental open-ground planting and high-porosity containers with cycles exceeding 24 months. The choice depends on the pot or site and the length of the cycle.
Do you also grow vegetable seedlings or potted plants? Go to /produzioni/piantine-da-orto/ or to /produzioni/piante-in-vaso/.
Want to test an Arber substrate in your outdoor nursery?
Request a quote, talk to the agronomist about your crop, or find your local retailer. Every request goes to your local sales agent, who contacts you directly.