Granusol® WSF

+25.9% More Large Fruit

Substrate Strawberry Production · UK

An independent season-long trial by DLV Plant UK at New Farm Produce (Lichfield, UK) demonstrates a significant increase in large-grade strawberries when using Granusol WSF compared to grower standard fertigation.

Trial Partner
DLV Plant UK Ltd
Duration
April – October
Location
Lichfield, UK, NL
Crop
Strawberry cv. Amesti
Treatments
4 total
LARGE FRUIT SHARE (>35mm)
0 %
MORE LARGE FRUIT (>35 mm)
+ 0 %
CLASS 1 FRUIT
0 %

Trial summary

This independent trial, conducted by Dennis Wilson (DLV Plant UK Ltd), evaluated Granusol Water Soluble Fertilizer against a bespoke grower fertigation programme in coir-grown, table-top strawberries.

The key commercial result:

Granusol delivered +25.9% more large fruit (>35 mm) compared to grower standard.

In high-value UK substrate strawberry production, fruit size directly determines packing efficiency, retail grade, and financial return. Large berries reduce sorting losses and increase Class 1 output.

Treatment 2 — Plain Coir + Granusol — produced:

  • 41.8% large berries (≥35 mm)

  • 98.1% Class 1 fruit

  • 100.9 g/plant (highest first-flush yield)

The driver? A consistently lower substrate EC during the critical fruit-swell phase (weeks 4–8).

Trial objective

UK substrate strawberries are managed intensively. Growers fine-tune EC to balance vegetative growth, fruit load and size.

The objective of this trial was not simply to match yield, but to evaluate:

  • Fruit size distribution

  • Class 1 percentage

  • Root-zone EC dynamics

  • Performance under real UK water conditions

Because in strawberries, EC management defines berry size.

Trial setup

The trial was carried out at a commercial grower’s site under real production conditions, ensuring all results are directly applicable to practice.

VARIETY

Strawberry cv. Amesti

Day-neutral, cold-stored Frigo plants

SYSTEM

Haygrove Polytunnel

Commercial double-row table-top system

SUBSTRATE

Coir (Legro BV)

Washed & buffered coco-fibre

PLANT SCALE

420 Plants

Per treatment · 35 troughs × 12 plants

DURATION

27 Weeks

April – October growing cycle

INDEPENDENT ANALYSIS

NRM Laboratories

Leaf tissue (6 dates) & substrate (4 dates)

Four Treatments Compared

TREATMENT 1

Horti-Cote® + Granusol

Coir pre-mixed with Horti-Cote CRF + Granusol WSF fertigation programme throughout the season.

TREATMENT 2

Plain Coir + Granusol

Granusol WSF fertigation only.

TREATMENT 3

Horti-Cote® + Grower Feed

Coir with Horti-Cote CRF + bespoke straight-fertilizer fertigation programme.

TREATMENT 4

Plain Coir + Grower Feed

Standard grower control treatment using bespoke straight-fertilizer recipe.

Results

Western Flower Thrips infestation in August compromised the second flush. Therefore, first flush (June–July) provides the most reliable performance comparison.

LARGE FRUIT SHARE (≥35 MM) — 1ST FLUSH (JUNE–JULY)
T4 — Plain Coir + Grower Feed (Control)
33.2%
Baseline
T1 — Horti-Cote® + Granusol
34.6%
+4.2% vs. control
T3 — Horti-Cote® + Grower Feed
30.6%
−7.8% vs. control
T2 — Plain Coir + Granusol
41.8%
+25.9% vs. control
Source: DLV Plant UK Ltd trial at New Farm Produce (Lichfield, UK), April–October. Strawberry cv. Amesti (day-neutral), coir substrate. First flush (June–July) used as main comparison window. Metric shown: share of large berries (≥35 mm).

Granusol WSF increases large-berry share under commercial UK conditions

In the first flush (June–July), Plain Coir + Granusol achieved 41.8% large fruit (≥35 mm) compared to 33.2% under grower standard practice. This represents a 25.9% increase in large-grade berries during the most reliable yield window of the trial.

For substrate-grown strawberries, fruit size directly determines packing efficiency, Class 1 percentage and market value. A higher proportion of large berries translates into measurable commercial advantage.

Conclusion

The independent UK substrate strawberry trial demonstrates that Granusol WSF positively influences fruit size distribution and grading performance under commercial coir conditions, resulting in a measurable improvement in marketable yield.

+25.9% More Large Fruit

Plain Coir + Granusol delivered a 25.9% increase in large-grade berries (>35 mm) versus the grower standard in the first flush.

Highest Class 1 Percentage

The same treatment achieved the highest Class 1 percentage (98.1%), supporting stronger commercial grading and pack-out efficiency.

Highest First-Flush Yield

Plain Coir + Granusol produced the highest first-flush yield (100.9 g/plant), the most reliable performance window of the trial.

Strongest Commercial Outcome

For UK coir-grown strawberries, Plain Coir + Granusol delivered the strongest overall commercial result across size, grade and first-flush yield.

Recommendation

For growers producing strawberries in coir under UK water conditions, Granusol WSF represents a competitive and practical fertigation solution. The combination of Plain Coir + Granusol delivered the strongest grading outcome in this trial and warrants further validation in higher-intensity production systems.

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Trial conducted by DLV Plant UK Ltd at New Farm Produce · Lichfield, United Kingdom · April–October · Crop: Strawberry cv. Amesti (day-neutral) · Granusol WSF supplied by Mivena BV. Results reflect independent trial data from a single commercial substrate grower location. Individual results may vary depending on water quality, substrate type, local climate conditions, variety, and crop management. © Mivena BV · Sprangseweg 13C · 5144 NV Waalwijk · info@mivena.nl 

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