Strawberry Cultivation and Propagation Methods

Strawberry Cultivation

• Strawberries (Fragaria × ananassa) are a hybrid of F. virginiana and F. chiloensis. They are cultivated from wild species. A shift from wild to cultivation began in the 1300s.
• US strawberry production is high, at 3 billion pounds annually (2012 data). The acreage harvested is 56,140 acres (2012). A small greenhouse area is 22 acres (2009).
• European protected strawberry culture is significant in several countries like the Netherlands (125 ha), Belgium (200 ha), Italy (150 ha), and parts of Northern France, UK, Switzerland, Germany, and Austria.

Propagation Methods

• Rooted Runner Plugs (Fresh Green Plants): These are rapidly rooted cuttings that are frequently misted. They grow to 3-5 true leaves and reach a 1cm+ crown diameter.
• Frigo plants: One-year-old plants dug from the field, trimmed, and stored at -2°C for months. These plants often have flower buds and yield fruit quickly, though some cultivars are less suitable for this storage method.
• Dormant Runner Plants: Young plantlets are dug in fall and stored at 2-4°C for spring planting. Runners and flowers from this nursery stage should be removed.
• Seeds: Development from crossing near-isogenic lines offers potential but is challenging. Seed-propagated cultivars are gaining interest.

Production Systems and Substrates

• Gutters and Modified Dutch Buckets: Common irrigation and planting methods using porous media needing frequent irrigation.
• Substrates: Strawberries need high oxygen levels in their root zone. A mixture of 50% perlite, 25% coconut coir, and 25% peat is recommended. Maintain pH 5.5–6.0 and electrical conductivity (EC) up to 1.0. (sensitive to high salts).
• Irrigation: Strawberries need consistent moisture. Common practice is pulse irrigation (about 33 mL per watering). Watering frequency varies depending on greenhouse conditions and plant growth.

Mineral Requirements and Flowering

• Potassium (K) and Iron (Fe): Important nutrients for growth. Maintain a N:K ratio of 1:1.7 or 1:2. Cool temperatures can trigger iron deficiencies.
• Flowering Habits: Strawberries have three types of flowering habits: day-neutral, short-day, and long-day.

Pests and Diseases

• Botrytis: A major shoot pathogen.
• Phytophthora: A significant root zone pathogen.
• Non-recirculating nutrient solutions: Used in substrate culture to prevent issues.
• Individual containers (BATO buckets): Compared to gutters (or NFT or deep flow), each has its own benefits concerning substrate use.

Post-Harvest Handling

• Strawberries are delicate and easily bruise. Handle them carefully.
• Avoid hydro-cooling as Botrytis is more likely to occur.

Conclusion

• Strawberries are a profitable greenhouse crop.
• While growing is not easy, the high value and interest in them make the effort worthwhile.