How to Grow Kiwi Fruit in a Greenhouse UK
Kiwi fruit (Actinidia deliciosa) grows successfully in UK greenhouses when trained on horizontal wires at 40-50cm intervals and kept above 10C in winter. The self-fertile variety Jenny produces fruit in 3-4 years without needing a separate male plant. Hardy kiwi berries (Actinidia arguta 'Issai') survive unheated greenhouses down to -15C and fruit in 2-3 years. A single mature vine yields 30-50kg of fruit per season in an 8x10ft or larger greenhouse, making kiwi one of the highest-value crops you can grow under glass in the UK.
Key takeaways
- Jenny is the best variety for most UK greenhouse growers. Self-fertile, so you only need one plant. Produces full-size fuzzy kiwi fruit in 3-4 years.
- Train vines on horizontal wires at 40-50cm spacing. A T-bar or espalier framework gives the vine structure. Kiwi grows 3-6 metres in a single season without training.
- Keep above 10C in winter, below 27C in summer. An electric fan heater and automatic vent openers handle both extremes without daily intervention.
- Hand-pollinate with a soft brush if growing indoors. Bees cannot access greenhouse flowers. Transfer pollen from stamens to stigma on open flowers in May-June.
- Prune twice: summer pinching and winter framework cuts. Summer: pinch shoots 4-5 leaves beyond fruit. Winter: cut lateral shoots back to 3-4 buds.
- Water heavily in summer, almost nothing in winter. Kiwi vines are thirsty plants from April to September but rot in waterlogged soil during dormancy.
Matt's note
I have been fitting greenhouses across the UK for over 16 years and kiwi is one of the most underrated crops you can grow under glass. Customers who plant a Jenny vine in an 8x10 greenhouse are genuinely shocked when it produces 30-40kg of fruit three years later. The vine itself is beautiful too. The heart-shaped leaves and twisting stems look like an ornamental climber until the fruit appears. The key mistake I see is people underestimating how fast kiwi grows. Without pruning, a single vine will fill a 10x12 greenhouse in two seasons. Train it properly from day one and you will have fruit for 30 years.
Which kiwi variety should you grow in a UK greenhouse?
Three kiwi species grow well in UK greenhouses. Each suits a different setup and climate. The right choice depends on your greenhouse size, whether you heat it in winter, and how patient you are.
Actinidia deliciosa 'Jenny' is the top choice for most growers. It is self-fertile, so you only need one plant. It produces standard-size fuzzy kiwi fruit identical to supermarket kiwis. Jenny fruits in 3-4 years from planting. It needs winter temperatures above 5C and summer temperatures below 27C. This variety suits heated or well-insulated greenhouses in all UK regions. A single mature vine produces 30-50kg of fruit per season.
Actinidia deliciosa 'Hayward' is the commercial standard. It produces larger fruit than Jenny with superior flavour. The catch is that Hayward is female-only and needs a male pollinator plant (usually 'Tomuri') planted within 3 metres. You need space for two vines, which means a 10x12ft greenhouse minimum. Hayward is the better choice if you have the room. Plant one male for every six to eight female vines.
Actinidia arguta 'Issai' is the hardy option. This species produces small smooth-skinned kiwi berries that you eat whole, skin and all. Issai is self-fertile, tolerates temperatures down to -15C, and fruits in just 2-3 years. It is the best choice for unheated greenhouses and cold frames. The fruit is smaller (grape-sized) but the flavour is sweeter than standard kiwi. Read our guide to growing fruit at home for more on choosing fruit varieties for your greenhouse.
| Variety | Species | Self-fertile? | Fruit size | Years to fruit | Min winter temp | Best for |
|---|---|---|---|---|---|---|
| Jenny (Matt's Pick) | A. deliciosa | Yes | Standard (60-80g) | 3-4 | 5C | Most greenhouse growers |
| Hayward | A. deliciosa | No (needs male) | Large (80-120g) | 3-4 | 5C | Larger greenhouses, best flavour |
| Issai | A. arguta | Yes | Small berry (8-15g) | 2-3 | -15C | Unheated greenhouses, cold regions |
| Tomuri (male) | A. deliciosa | Pollinator only | No fruit | N/A | 5C | Pollinator for Hayward |
What size greenhouse do you need for kiwi?
A single kiwi vine needs a greenhouse that is at least 8x10ft (2.4m x 3m). The vine will fill this space within 2-3 years when trained on wires. For two vines (one male, one female), you need 10x12ft (3m x 3.6m) minimum. Space plants 3-3.5 metres apart.
Eave height matters more than floor space for kiwi. The vine grows vertically before being trained horizontally. A greenhouse with 1.5m eave height and 2.5m ridge height gives the best growing structure. The lowest training wire sits at 60cm, with two or three horizontal tiers above it at 40-50cm intervals up to the eaves.
If you are choosing a new greenhouse for kiwi growing, consider our aluminium greenhouse range. Aluminium frames are ideal for attaching training wires with bolt-on clips.
How to set up training wires for kiwi vines
Training wires are the single most important element of kiwi growing. Without them, the vine grows into an unmanageable tangle within one season. Install wires before planting.
Run horizontal galvanised wire along the longest wall of your greenhouse at 40cm, 80cm, 120cm, and 160cm from the ground. Fix each wire to the aluminium frame using stainless steel vine eyes or wire clips bolted through the glazing bar. Tension wires taut with turnbuckles at each end. The wires need to support 15-20kg of fruit plus foliage when the vine matures.
Shop Elite Wire Clips (50 pack) £30 →
Plant the kiwi at the base of the wire system. Train one main stem (the leader) vertically up a bamboo cane to the top wire. As lateral branches develop, tie them horizontally along each wire using soft garden twine. Remove any shoots growing away from the wire framework. This makes a flat, fan-shaped structure that maximises light exposure to every leaf and fruit.
Planting and soil preparation
Plant kiwi vines in late spring (April-May) when the risk of frost has passed. Dig a planting hole 60cm wide and 45cm deep at the base of your wire framework. Mix the excavated soil with well-rotted garden compost at a 50:50 ratio. Kiwi needs well-drained but moisture-retentive soil with a pH of 5.5-7.0.
If planting directly into greenhouse borders, improve drainage by adding a 10cm layer of gravel at the base of the planting hole. If your greenhouse has a concrete base, grow in a large container (minimum 50-litre pot) filled with John Innes No.3 compost mixed with perlite for drainage.
Water the new plant thoroughly after planting. Apply a 5cm mulch of bark chips or garden compost around the base, keeping it 5cm away from the stem to prevent rot. Kiwi roots are shallow and benefit from mulch that keeps them cool and moist in summer.
Temperature management: the key to UK kiwi success
Temperature control is where greenhouse kiwi growing succeeds or fails in the UK. The vine needs warmth to grow and fruit but suffers in extreme heat. Getting this balance right across all four seasons is the challenge.
Spring (March-May): New shoots are extremely vulnerable to late frosts. Keep the greenhouse above 7C at night until mid-May. An electric fan heater with a thermostat set to 7C handles this automatically. Open vents during the day when temperatures exceed 18C.
Summer (June-August): Kiwi grows fastest at 20-25C. Above 27C, growth slows. Above 35C, pollen dies and fruit set fails. Automatic vent openers are essential. Damp down the greenhouse floor 2-3 times daily in heatwaves to lower air temperature by 3-5C. Read our ventilation guide for detailed temperature management advice.
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Autumn (September-November): Allow temperatures to drop gradually as the vine prepares for dormancy. Stop feeding in September. Reduce watering from October. The leaves will yellow and drop naturally in November.
Winter (December-February): Kiwi needs a cold period (vernalisation) to set fruit the following year. The vine must experience 600-800 hours below 7C during winter dormancy. In an unheated greenhouse, this happens naturally. If you heat your greenhouse, set the thermostat to 5C minimum to prevent frost damage to the trunk while still allowing the cold period. Do not heat above 10C in winter or the vine will not fruit properly the following year.
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Matt's installation tip: ventilation for kiwi
I always recommend fitting at least two automatic vent openers when a customer plans to grow kiwi or grapes. The wax cylinder inside the opener reacts to temperature and starts opening the vent at 15C. By 25C the vent is fully open. This means your kiwi vine never overheats, even if you are at work all day. The Elite automatic louvre vent opener costs £59 and saves you from losing an entire fruit crop to one hot afternoon. I have seen it happen more than once.
How to pollinate kiwi in a greenhouse
Greenhouse-grown kiwi must be hand-pollinated because bees and other insects cannot access the flowers through glass. This is the step most beginners forget, and it results in a vine that grows but produces no fruit.
Kiwi flowers open in May-June. They last 3-5 days each. Use a small soft paintbrush or cotton bud to collect yellow pollen from the stamens of an open flower. Transfer this pollen to the stigma (the central sticky part) of another flower. Repeat for every open flower. Do this daily for 2-3 weeks during the flowering period.
If you are growing a self-fertile variety like Jenny, you still need to transfer pollen between flowers on the same plant. The flower structure means wind alone is not enough indoors. A gentle shake of the vine combined with brush work gives the best fruit set. Our fruit growing guide covers hand pollination technique in more detail.
Pruning: summer pinching and winter framework
Kiwi grows 3-6 metres of new growth per season. Without pruning, the vine becomes a dense tangle that shades its own fruit and fills the greenhouse. Prune twice a year: a light summer pinch and a harder winter cut.
Summer pruning (June-August): Pinch or cut the growing tip of each fruiting shoot 4-5 leaves beyond the last fruit. This directs energy into the fruit rather than leaf growth. Remove any shoots growing straight up or away from the wire framework. Remove suckers from the base of the trunk.
Winter pruning (December-January): Once the leaves have dropped, cut each lateral shoot back to 3-4 buds from the main framework wire. Remove any dead, damaged, or crossing branches. Remove one-quarter of the oldest lateral branches each winter to encourage new productive wood. Keep the main leader and primary arms untouched unless they have outgrown the greenhouse.
Sharp bypass secateurs make clean cuts that heal quickly. Read our common greenhouse growing mistakes guide for more on the consequences of skipping pruning on vigorous crops.
Watering and feeding
Kiwi vines are heavy drinkers during the growing season (April-September). Water deeply 2-3 times per week in summer, more often during hot spells. The soil should be consistently moist but never waterlogged. Shallow watering encourages surface roots that dry out quickly.
From October to March, reduce watering dramatically. The dormant vine needs almost no water. Waterlogged soil during winter dormancy causes root rot, which is the most common reason for vine death in UK greenhouses.
Feed with a high-potassium liquid fertiliser (tomato feed works well) every two weeks from April to August. Switch to a phosphorus-rich feed when flowers appear in May to improve fruit set. Stop feeding entirely in September to help the vine harden off before winter.
Month-by-month growing calendar
| Month | Task | Temperature |
|---|---|---|
| January | Winter pruning. Cut laterals to 3-4 buds. Remove oldest wood. | Keep above 5C |
| February | Check wire tensions. Repair any frost-damaged branches. | Keep above 5C |
| March | New growth begins. Start watering lightly. Apply first feed. | Min 7C at night |
| April | Tie new shoots to wires. Increase watering. Feed fortnightly. | 10-20C ideal |
| May | Flowers open. Hand-pollinate daily. Watch for late frost. | 15-25C ideal |
| June | Summer pruning begins. Pinch shoots 4-5 leaves beyond fruit. | 18-25C ideal |
| July | Continue pruning. Water heavily. Damp down in heatwaves. | Keep below 27C |
| August | Fruit swelling. Maintain watering. Last summer prune. | Keep below 27C |
| September | Stop feeding. Reduce watering. Fruit begins to ripen. | Let cool naturally |
| October | Harvest when fruit gives slightly to thumb pressure. | Let cool naturally |
| November | Leaves drop. Stop watering. Clean up fallen leaves. | No heating yet |
| December | Dormant. Start winter pruning late December. | Keep above 5C |
Harvesting and storing kiwi fruit
Kiwi fruit ripens in October-November in UK greenhouses. The fruit does not all ripen at once, so harvest over 3-4 weeks. Pick when the fruit gives slightly to gentle thumb pressure. Unripe fruit can be picked hard and ripened indoors at room temperature over 1-2 weeks.
Store harvested kiwi in a cool place (4-8C) for up to 3 months. A garage, unheated porch, or the fridge works well. To speed up ripening, place kiwi in a paper bag with a banana. The ethylene gas from the banana triggers ripening within 3-5 days.
A single mature Jenny vine produces 30-50kg of fruit per year. That is roughly 400-600 individual kiwis. Most growers end up giving fruit away to neighbours, which is not a bad problem to have.
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Matt's pick: essential for kiwi growingBest For: Monitoring overnight lows and daytime highs in your kiwi greenhouse Why I Recommend It: The ETI digital thermometer records maximum and minimum temperatures over 24 hours. I tell every kiwi grower to check the min reading each morning from March to May. If it dropped below 7C overnight, your new shoots are at risk and you need to adjust your heater thermostat. This one tool prevents the most common cause of failed kiwi crops: spring frost damage to new growth. Price: £44 |
Common problems and solutions
No fruit after 4+ years: The three most common causes are insufficient winter chill (keep greenhouse below 7C for 600+ hours), failed pollination (hand-pollinate daily during flowering), or excessive nitrogen fertiliser (switch to high-potassium feed).
Leaf scorch and wilting in summer: Temperature above 27C. Improve ventilation with automatic vent openers. Damp down the greenhouse floor. Apply temporary shade paint to south-facing glass panels.
Root rot and vine death: Overwatering during winter dormancy. Reduce watering from October. Improve drainage in the planting hole. Never let the root zone sit in standing water.
Small or misshapen fruit: Poor pollination. Hand-pollinate more thoroughly next season. Use a soft brush rather than just shaking the vine.
Vine growing too fast, no fruit: Too much nitrogen. Stop using general-purpose fertiliser. Switch to tomato feed (high potassium, low nitrogen) from April onwards.
Frequently asked questions
Can you grow kiwi fruit in an unheated greenhouse in the UK?
Yes, hardy kiwi berries (Actinidia arguta 'Issai') survive down to -15C. This variety produces small smooth-skinned fruit in unheated greenhouses across all UK regions. Standard fuzzy kiwi (Actinidia deliciosa) needs winter heating above 5C, which means an electric heater with thermostat in most parts of the UK.
How long does kiwi take to fruit in a greenhouse?
Most varieties fruit in 3-4 years from planting. Hardy kiwi berries (Issai) can fruit in 2-3 years. The vine grows vigorously from year one but directs energy into establishing roots and framework before fruiting. Patience and consistent pruning produce the best long-term yields.
Do you need two kiwi plants to get fruit?
Not if you grow a self-fertile variety like Jenny or Issai. These produce fruit from a single plant. The variety Hayward is female-only and needs a male pollinator plant (Tomuri) within 3 metres. One male pollinates up to eight female plants.
How do you pollinate kiwi in a greenhouse?
Use a soft paintbrush to transfer pollen between flowers. Kiwi flowers open in May-June. Touch the brush to the yellow stamens of one flower, then dab the sticky stigma of another. Repeat for every open flower daily for 2-3 weeks during the flowering period.
What temperature does kiwi need in a greenhouse?
Growing season: 18-25C ideal, never above 27C. Winter dormancy: 5-7C minimum, with 600-800 hours below 7C needed for vernalisation. Spring: protect new shoots from frost, keep above 7C at night from March to May.
When do you harvest kiwi from a greenhouse in the UK?
October to November in most UK regions. Pick when fruit gives slightly to gentle thumb pressure. Unripe fruit can be picked hard and ripened at room temperature over 1-2 weeks. Store ripe fruit at 4-8C for up to 3 months.
How much fruit does one kiwi vine produce?
A mature vine yields 30-50kg of fruit per season. That is roughly 400-600 individual kiwi fruits from a single plant. Yields start small in year 3-4 and increase annually until the vine reaches full maturity at 8-10 years old.
