With five SPELAND product lines covering propagation through full production, the question "which substrate do I need?" is one we answer for growers every day. This guide provides a straightforward decision framework based on crop type, growing stage, and system design.
Step 1: Identify Your Growing Stage
Stone wool substrates are format-specific. The physical shape and density are optimised for the specific phase of growth — you can't use a fruiting slab for propagation, and plugs won't support a full-season crop.
| Growing Stage | SPELAND Product | Format |
|---|---|---|
| Seed germination, cutting propagation | SPELAND Base | Small cylindrical or cubic plugs in trays |
| Seedling / transplant stage | SPELAND Mid | Growing cubes (7.5×7.5×6.5 cm etc.) |
| Full-season vegetable production | SPELAND Vega | Long slabs (100+ cm) |
| Microgreens / baby leaf | SPELAND Micro Green | Thin flat tiles |
| Cut flower production | SPELAND Floret | Slabs with optimised density for woody stems |
Step 2: Match to Crop Type
| Crop | Recommended Products |
|---|---|
| Tomato (greenhouse) | Base → Mid → Vega |
| Cucumber (greenhouse) | Base → Mid → Vega (20 cm wide) |
| Pepper (greenhouse) | Base → Mid → Vega |
| Rose (cut flower) | Base (cutting propagation) → Floret |
| Gerbera / Chrysanthemum | Base → Floret |
| Microgreens (commercial) | Micro Green tiles |
| Lettuce (seedling stage) | Base or Micro Green |
| Herbs (basil, parsley) | Base → Micro Green (for production) |
| Strawberry | Vega (modified configuration) |
Step 3: Consider Your System Design
Drip Irrigation onto Slabs
The most common commercial setup. All SPELAND Vega and Floret slabs are designed for drip irrigation. Ensure slab length matches your row spacing and that the number of plants per slab is appropriate (typically 1–2 plants per 100 cm slab).
Flood-and-Drain / Ebb-Flow
Stone wool cubes (SPELAND Mid) work well in ebb-flow systems — the substrate absorbs from below and drains quickly. Avoid using slabs in ebb-flow as lateral flow distribution is limited.
NFT / DWC
Stone wool plugs (SPELAND Base) are commonly used in NFT and DWC for seedling support — plants are rooted in the plug, then placed in the channel or raft. The plug is not the primary root medium in these systems.
Propagation Rooms (Controlled Environment)
SPELAND Base and Mid are designed for propagation environments with controlled humidity and temperature. They can be stacked, transported, and handled mechanically without damage to seedling roots.
Step 4: Calculate Your Volume
Slabs (Vega / Floret)
Calculate: (greenhouse area m²) ÷ (row width m) × (plants per metre) ÷ (plants per slab) = number of slabs needed. Add 10% buffer for quality checks and broken slabs.
Cubes (Mid)
One cube per plant. Calculate: total plants × 1.05 (5% buffer for failed germinations and breakage).
Plugs (Base)
One plug per seed (for direct seeding) or cutting. Calculate: (plants needed) ÷ (expected germination rate %). For most vegetable seeds, germination in stone wool plugs is 90–98% — so plan for ~5% extra.
Step 5: Plan for the Full Cycle
The most cost-effective approach to stone wool substrate management:
- New slabs every season for annual crops (tomato, cucumber in single-season systems)
- For rose and perennial crops: slabs for 5–7 years; replace when drainage time increases significantly (sign of compaction)
- Cubes and plugs: single use always
- Budget substrate cost as 3–7% of total crop production cost — never a place to cut corners
Getting Help from Vator LLC
Our team works with growers at every scale — from single-tunnel greenhouses to multi-hectare operations. We can help you:
- Select the right SPELAND product for your crop and system
- Calculate exact volumes for your growing area
- Provide agronomic guidance on EC, pH, and irrigation protocol
- Arrange export packaging and logistics for your country