Raspberries in tunnels — which tunnel to choose
Raspberries need a tunnel with tall sides: US guidance from Utah State University calls for sidewalls of at least 5–6 feet (about 1.5–1.8 m), so that the canes fit and cross-ventilation works. The cover protects the fruit from rain, so according to UC IPM there is less fruit rot, including grey mould.
Why grow raspberries under polythene
In the open field, raspberries are sensitive to rain during flowering and harvest. A tunnel reduces this problem. Sources from North American universities and advisory services list similar benefits:
- Less fruit rot. The University of Guelph (in material on the Ontario government website) writes that in a tunnel many fungal diseases are reduced or eliminated, especially fruit rots. UC IPM states that plants protected from moisture suffer less often from fruit rots such as grey mould (Botrytis) and anthracnose.
- Longer shelf life after harvest. According to the University of Guelph, fruit grown under cover keeps noticeably longer.
- An earlier start and better quality. The same material lists earlier production and better fruit quality.
- A longer season in autumn. Utah State University describes the tunnel as a way to extend the harvest of primocane cultivars: it protects against the first frost, which ends the season in the open field.
UC IPM also states that in Californian tunnels the fruit is 20–25% larger and yields are 30% or more higher, depending on location and conditions. These are figures from California.
The other side of the coin: heat and spider mites
Cover is not all upside. UC IPM warns that tunnels overheating can be a serious problem, and that warm, dry conditions favour two-spotted spider mite and whitefly. High humidity in a closed tunnel still favours grey mould. That is why ventilation is part of the growing system, not an extra.
Chemical protection also differs from the open field. According to the IO-PIB protection programme for raspberries under cover (2026), no chemical herbicides are currently registered for tunnels and glasshouses with raspberries. The soil is mulched, and weeds are controlled mechanically or physically.
Primocane or floricane raspberries
| What it fruits on | second-year canes | first-year canes, in autumn |
|---|---|---|
| Training according to IO | hedgerow on a post-and-wire structure, canes tied in | usually no supports; after harvest all canes are cut at ground level |
| In a tunnel | needs room for long canes and a support structure | Utah State University recommends setting the tunnel up for an autumn harvest |
The IO guidelines on integrated protection of raspberry list 13 floricane and 12 primocane cultivars in the Polish National List of varieties. The figure dates from when the guidelines were written, so check the current list with COBORU (the Polish Research Centre for Cultivar Testing).
For primocane crops, Utah State University advises focusing on the autumn harvest in a tunnel. The recommendation: cut the canes at ground level during winter dormancy and choose late cultivars with large fruit.
Soil or pots
Growing in the soil
IO-PIB recommends fertile soils with a good balance of air and water for raspberries. It rules out soils that are too heavy and poorly drained, because even brief waterlogging of the roots causes them to die and encourages root rot. Utah State University adds that on poorer soils raspberries can be planted on raised beds. It also advises against planting them after tomatoes, potatoes, aubergines or strawberries for 4–5 years, because of Phytophthora root rot.
IO also warns against planting too densely: it encourages fungal diseases and reduces the effectiveness of treatments.
Pots and substrate (long cane)
Perennia (Canada) describes long cane production: raspberries grow in soilless substrate under cover. It cites a predictable yield thanks to less rain damage, and lower disease pressure thanks to shorter cycles than in the soil. According to Perennia, a long cane is a fully grown cane 1.4–2 m tall.
Pots make the crop independent of the soil, but they require precise irrigation and feeding.
How tall a raspberry tunnel should be
Raspberries need more vertical space than strawberries. A long cane, plus the support structure, plus a person picking, is the dimension you start from when choosing a tunnel.
| Parameter | Value in the source | Source |
|---|---|---|
| Tunnel sidewall | at least 5–6 feet (about 1.5–1.8 m) | Utah State University |
| T-trellis crossbar | about 5–6 feet (about 1.5–1.8 m) above the ground | Utah State University |
| Tunnel height | usually 10–15 feet (about 3–4.6 m) | UC IPM, California |
| Long cane height | 1.4–2 m | Perennia |
Utah State University adds that when choosing a tunnel you need to take account of wind, snow load and the crop. The tunnel can be single or multibay. Openings in the end walls improve ventilation, and the tunnel can be built so that a small machine can drive in.
What we offer for raspberries
- tunnels up to 5 m high on upset anchors (1.25–2.0 m),
- Y-legs in multibay tunnels, screwed into the soil, 2.5–3.5 m long,
- bay width 6–11 m, round or gothic arch,
- gutters and rainwater collection in multibay tunnels,
- legs and anchors in E370+Z275 steel, hoops in S350+Z275 steel,
- single film 150–200 µm with a 3-year warranty.
We match the configuration during a visit to the customer, to the row spacing, training system and machinery.
Single or multibay
For larger raspberry plots, multibay tunnels have the advantage: shared rows of legs, gutters between the bays and a lower cost per m². A single tunnel is warmer inside, which helps with very early crops. With raspberries, however, you need to watch out for overheating, which UC IPM writes about.
Start with the configurator or see raspberry tunnels.
Sources
- Program ochrony maliny pod osłonami (marzec 2026) [Protection programme for raspberries under cover, March 2026], Instytut Ogrodnictwa – PIB, Skierniewice (accessed 11 October 2026)
- Metodyka integrowanej ochrony maliny (materiały dla producentów) [Integrated protection of raspberry — guidance for growers], Instytut Ogrodnictwa, Skierniewice (accessed 11 October 2026)
- Growing raspberries in tunnels and greenhouses: basic concepts — A. Dale, University of Guelph, Ontario.ca (accessed 11 October 2026)
- Tunnel Culture — UC IPM Pest Management Guidelines: Caneberries (UC ANR Publication 3437) (accessed 11 October 2026)
- Fall-bearing Raspberries in High Tunnels — D. Rowley, B. Black, D. Drost, Utah State University Extension, 2009 (accessed 11 October 2026)
- Long Cane Raspberry Production Guide — Perennia Food and Agriculture (accessed 11 October 2026)