The Role of Protected Growing in Poland's Vegetable Sector
Poland is among the larger vegetable-producing countries in the European Union, with outdoor field production of cabbage, onion, carrot and other field crops forming the bulk of output. Protected horticulture — greenhouse and tunnel production — occupies a smaller but economically significant share of the sector, concentrated on high-value crops such as tomatoes, cucumbers, sweet pepper and leafy salads where consistent quality and early or late-season production create a premium.
The foil tunnel area in Poland is estimated to represent the majority of protected vegetable production, with glass greenhouse operations concentrated in the larger commercial holdings in the Mazowieckie, Łódź, Kujawsko-Pomorskie and Małopolskie regions. The Instytut Ogrodnictwa in Skierniewice publishes technical guidance on protected crop production that is widely referenced by growers across the country.
Tomatoes: The Dominant Greenhouse Crop
Tomatoes are the principal crop in Polish greenhouse production by both area and value. The variety of production systems in use reflects the range of structure types: from substrate culture on rockwool or coconut coir slabs in climate-controlled glass greenhouses to soil-grown plants in mid-tech foil tunnels. The production calendar varies accordingly.
Planting Calendar
On heated glass operations targeting early production, seed sowing for the main tomato crop typically takes place in December or January, with transplanting to the final growing position in late January or February. First harvest on high-wire indeterminate varieties can begin in April. This schedule requires maintaining minimum night temperatures of 16–18 °C through the coldest part of the year, which represents a significant heating cost in Poland.
On unheated or minimally heated foil tunnels — the majority of Polish operations — sowing is moved to February or March, transplanting takes place in April under cover, and harvest runs from late May or June through October. This calendar avoids the heating costs of winter production while still providing six to seven months of covered growing season.
Substrate and Irrigation
Soil-grown tomatoes in foil tunnels are typically planted into the existing topsoil with organic matter supplementation. Raised beds or ridges are used to improve drainage and early soil warming. Drip irrigation is standard practice on both soil and substrate systems, delivering water and soluble fertiliser in multiple small doses throughout the day. The frequency and volume are adjusted to substrate moisture readings or tensiometer values in more advanced installations.
Rockwool slabs have been the dominant substrate in glass greenhouse tomato production in Poland since the 1990s. They are inert, have a consistent water-holding capacity and allow precise EC (electrical conductivity) and pH management of the nutrient solution. Coconut coir slabs are a more recent alternative with similar performance characteristics but a renewable origin.
Cucumbers
Greenhouse cucumbers in Poland are grown primarily as indeterminate high-wire plants, trained vertically on strings or a trellis system. Modern Dutch-type parthenocarpic varieties (setting fruit without pollination) have largely replaced older open-pollinated types in commercial production because they produce uniform, seedless fruit suited to retail markets.
Cucumbers are faster-developing than tomatoes and are more sensitive to temperature fluctuations. A minimum growing temperature of 18 °C is typically maintained through the night in production aimed at the early market. On unheated foil tunnels, the cucumber season is therefore shorter than tomatoes — typically May to September — and planting is deferred until soil and air temperatures are reliably above 15 °C.
Succession Planting
On heated glass greenhouses where cucumbers are grown year-round or in two distinct crops, succession planting is used. A typical two-crop system involves a main crop planted in January or February, running until June, followed by a second crop planted in July and harvested through November. Between crops, the structure undergoes cleaning and substrate sterilisation or replacement.
Sweet Pepper
Sweet pepper (paprika) is grown on a smaller area than tomato or cucumber in Polish protected production, primarily because of its longer development cycle and requirement for consistently warm night temperatures. The crop is typically started from seed in November or December for heated glass operations, or in February for foil tunnel production with supplementary heating.
Pepper is particularly sensitive to calcium deficiency at the fruit level (blossom end rot) and to irregular water supply. Stable drip irrigation management and adequate ventilation to prevent high relative humidity around the developing fruit are the main cultural requirements distinguishing successful pepper production from tomato or cucumber growing.
Leafy Salad Crops
Lettuce, spinach, rocket and mixed salad leaf production under cover occupies a distinctive position in Polish protected horticulture because it addresses the shoulder seasons — October through April — when outdoor salad supply from field production is absent. Unheated or lightly heated foil tunnels can extend the outdoor salad season by four to six weeks in autumn and achieve first harvest three to four weeks earlier than outdoor crops in spring.
Low Tunnel Production
Non-woven agrotextile covers over low hoops are used on a large scale for early spring lettuce and radish in Poland. The covers are typically left in place continuously until daytime temperatures exceed 15 °C, at which point they are removed or replaced with perforated film that provides lower thermal protection but allows some ventilation. Multiple sowings at two-week intervals provide a continuous harvest window without gaps.
In central Poland, a low-tunnel spinach crop sown in early March under non-woven agrotextile can be ready for first harvest by mid-April — roughly three to four weeks ahead of an equivalent outdoor sowing. The extension is shorter in warmer southern areas and longer in the cooler northeastern regions.
Crop Rotation and Disease Management
Continuous soilborne production of the same crop family in unsterilised greenhouse soil leads to the build-up of soilborne pathogens — Fusarium oxysporum on tomatoes, Pythium species on cucumber — within a few production cycles. Commercial growers using soil-grown systems in Poland typically rotate between crop families on a two- to three-year cycle or move to raised substrate culture to break the cycle.
Grafting tomatoes onto disease-resistant rootstocks is a widely practised solution for soilborne pathogen management in Polish commercial production. The most common rootstocks provide tolerance or resistance to Fusarium crown and root rot, Verticillium wilt and root-knot nematodes. Grafted transplants are available from specialist propagation nurseries or produced on-farm where volume justifies the investment in grafting and healing chambers.
Pollination Under Cover
Tomatoes and peppers require pollination for fruit set; cucumbers of the modern parthenocarpic types do not. On greenhouse tomato crops, bumblebee hives are placed within the growing structure as the standard approach. Bombus terrestris colonies reared for commercial horticulture are available from specialist suppliers and are introduced when first flowers open. A single hive is sufficient for a floor area of roughly 500–1000 m² depending on crop density and temperature. Bees work effectively between approximately 10 °C and 35 °C, which aligns well with the active growing temperature range of the tomato crop.
