How to Grow Kiwi: Expert Guide for Home Gardeners

At the outset, it's important to set realistic expectations about how to grow kiwi. A productive kiwifruit vine can average from 60-100 store-bought kiwifruit to harvest. Home growers will often achieve a harvest from 40-80 store-bought kiwifruit, having to employ organic methods to do so. These days, there is a great increase in modern cultivars that will thrive in USDA zones 3-9, allowing even northern gardeners to enjoy vine-ripened kiwi berries. I've grown Arctic Beauty through the winter in the state of Minnesota by utilizing the correct cold-hardy rootstock.

You will endure a trial of patience during the 3-5 year establishment phase, but the wait pays off! My first Issai vine flowered in Year 3, but I needed to hand-pollinate the flowers for that to happen and yield some fruit. Space your plants 10-15 feet apart on a T-trellis that is sturdy enough to handle the load. As your plants are establishing their root systems, apply biodegradable mulch to the base of your plants to suppress weeds.

Success depends on pairing varieties with microclimates. For example, wet coastal microclimates would be best planted with fuzzy types such as Hayward while arid microclimates should experiment with drought-tolerant varieties such as Kolomikta. I considered grafting survivorship on top of nematode-resistant rootstock a priority after suffering damage to vines early on in the crop cycle from soil-based pests.

Choosing a suitable kiwi variety for your climate depends on the winter lows you expect. Arctic Beauty can survive -40°F (-40°C) winter lows in USDA Zone 3, while Ken's Red can be safely grown even if temps dip to -15°F (-26°C) for brief periods. I successfully overwintered Issai Kiwis here in Zone 4b using straw mulch and wrapping them in a burlap sack overnight if those lows were expected. If you're concerned, check the microclimate in your garden before placing your order.

The Issai is unique in that it is the only known self-fertile kiwi, It produces fruits that are around the size of marble measuring 1.5 inches (3.8cm) without having to fertilize pollinate. If you want a larger yield, add a male plant, since my harvest tripled after one Tomuri male with eight Issai female plants around it. Just be careful to time the flowers so that they overlap.

Patience is a hurdle for commercial favorites like Hayward. These fuzzy kiwis are 2.5" (6cm) long first-year vines and need separate male pollinators to set fruit and require 225 frost-free days of growing time. I lost three vines before I figured out that my Zone 6 Kentucky winters ended the kiwis' growing season before they had a chance to set fruit. Be sure to match cultivars of kiwis to your last frost date for better results.

Avoid the letdown of missing out on pollination by learning when different kiwi plants bloom. For example, hardy kiwis bloom earlier than fuzzy kiwis. I keep track of the bloom time for my Vincent males about when my female Saanichton 12 begins to flower. I note the annual first flowering dates. I mark the male vines and female vines with string tags during their dormant time.

Source: commons.wikimedia.org

Issai Kiwi

• Self-fertile: Only variety needing no male pollinator
• Yield: 25-35 lbs per mature vine
• Size: 0.6-1" (1.5-2.5cm) long fruits
• Harvest: Mid-September in Zone 5
• Pollination: 30% yield boost with male plant
• Zones: 5-9 USDA

Source: freerangestock.com

Arctic Beauty

• Foliage: Pink-white variegated leaves
• Hardiness: Tolerates permafrost soils
• Fruit: 0.5" (1.3cm) berries
• Lifespan: 15-20 years maturity
• Light needs: Partial shade tolerant
• Zones: 3-7 USDA

Source: api-server.pexels.com

Ken's Red

• Color: Burgundy-red flesh when ripe
• Cold resistance: Survives ice storms
• Usage: Ideal for jams and fresh eating
• Vine span: 15-20ft (4.5-6m) spread
• Flowering: Late May to avoid frost
• Storage: 6 weeks refrigerated

Source: commons.wikimedia.org

Hayward Classic

• Commercial standard: 90% of global production
• Skin: Fuzzy brown protective layer
• Weight: 2.5-3oz (70-85g) average
• Shelf life: 6 months cold storage
• Pollination: Requires 'Tomuri' male
• Zones: 7-10 USDA

Source: identify.plantnet.org

Ananasnaya

• Flavor: Pineapple-like tanginess
• Texture: Smooth edible skin
• Growth rate: 12ft (3.6m) per year
• Disease resistance: High against canker
• Training: Requires heavy pruning
• Yield peak: Year 5-8

The success of a kiwi operation is based on soil pH. To bring the pH of clay soils down to the optimum pH of 5.5 - 6.5 you can add 2 lbs of elemental sulfur per 10 sq ft of soil. In sandy soils, adding 5 lbs of peat moss will help acidity. Every few months, I attempt to measure the pH of my garden using a $15 meter. Ground planting requires a hole of at least 18" depth, and 24" depth for taproots and containers.

For T-t- trellis systems, establish spacing where plants are 15 feet apart. Training on a pergola requires spacing of 12 feet apart. My first planting failed because of overcrowding, and I had roots tangled after three years. If you plant in pots, use 25-gallon grow bags. I have kept Issai container-grown for ten years, with root pruning each year.

Organic amendments (fertilizers) such as composted manure provide plants with slowly released nutrients. I apply a 4" layer in the fall. Synthetic 10-10-10 fertilizers release immediately and hasten growth but will also increase salt buildup in the soil eventually. I use fish emulsion in the spring and slow release in the summer. I do this every month for container plants; garden vines receive treatment every spring and again just before flowering, which is generally eight weeks before the beginning of flowering, (depending on the type of vine.)

Male-to-female ratios vary by cultivar, I have learned, but in general, you want to account for 1 male per 8 Hayward vines, or 1:4 for Ken's Red. I seem to have lost two seasons due to poor fruiting before I considered this important factor in vine spacing. Male vines produce pollen, female vines produce both fruit and bloom. If you have both male and female vines, label all the vines while the plants are dormant to help avoid a mix-up.

Identify gender differences by studying liquids. Male flowers display clusters of golden pollen atop short stems. In contrast, female flowers feature a distinctive white pistil surrounded by sterile anthers. Use a 10x magnifying glass when blooms are only slightly open, which is useful to help with identification. I keep one in my pruning toolbox.

Pollination is effective for 3-4 days after a flower opens. High humidity in the morning helps pollen stick. I will use a soft toothbrush to transfer pollen in the hours of 10 AM - 2 PM. Natural bee pollination achieves only a 30% fruit set, while manual methods achieve close to 80%.

Manual pollination outperforms anything that nature provides. My Issai vines produced 12 lbs/year with only bees. After hand-pollination, they produced 35 lbs! Once collected, all pollen can be stored in film canisters for 48 hours. Pollen clumps and does not transfer well if it rains.

Pruning during dormancy modifies growth for next season, remove 70% of old wood in the late winter. For USDA Zone 5, perform this work in February, before the sap rises. Summer pruning assists in managing vine vigor; simply prune new shoots to 8 leaves in June. I use different color ties every year to distinguish fruiting canes.

To avoid disease spread, make sure to disinfect tools between plants. I soak bypass pruners in 70% isopropyl alcohol for 10 minutes. If you're concerned with fire blight, use a solution containing 10% bleach. Sharpen blades at least weekly, if you are in peak season because dull tools make it difficult to cut stems and increase the possibility of added pathogens.

To identify fruit-bearing wood, look for nodes that mark last year's growth. Fruiting spurs will form on 1-year-old canes with 6-8 buds on them. I instruct apprentices to trace each cane to identify its origin, and if that cane is older than two seasons, remove it entirely. Renewal pruning can increase yields by 40%.

Timing differs from region to region. Zone 7 growers will typically prune in January whereas zones with the more extreme climate (like Zone 3) will prune in March. I demo prune with soil temperature, once the soil reaches 40 degrees F (4 degrees C), I would only make structural cuts. I do not prune when the sap is flowing in the vines, that weakens the vines and draws in borers.

The indicators of ripeness vary with the type of kiwi. For example, fuzzy kiwis, specifically the Hayward variety, soften at the blossom end and grow black seeds when the fruit is ripe. Kiwi berries, like the Arctic Beauty variety, turn translucent green and will drop off the vine when it's time to harvest. I suggest picking one berry or kiwi each week and tasting it. If it was sweet off the vine, pick the remaining fruit. I ruined my first crop by picking them too soon.

To store unripe kiwis, place them in perforated plastic bags and keep them at 32°F (0°C) for up to six months. If you would like to use ripe fruit, refrigerate them. For freezing, place slices that have been peeled on trays lined with parchment paper, and freeze before bagging. In 2022, I had fresh kiwis until March using this method. The only guideline is not to wash them before you put them in storage because moisture begets mold.

Utilize sharp snips to trim stems about 1/4" above the fruit. You should not pull or twist the vine; you can damage the spurs with this method. I keep my sterilized pruners in my harvest apron, which has a pocket for holding them. If you pick from a tall vine, use pole pickers, which have padded baskets, to avoid bruising the fruits.

Some of the top blunders include harvesting while it rains, which encourages rot, and mixing ripe/unripe fruit, which puts ethylene in overdrive. I know this after losing 15 lbs to premature softening. You want to separate the sizes of fruit since larger fruit will always ripen first. Do not stack kiwis more than three layers deep in your containers.

Learning how to grow kiwi requires staying power, since most vines take 3-5 years before producing fruit. My initial harvest occurred in Year 4, with Arctic Beauty, a variety that is forgiving of frost in the Midwest. Give young plants a lot of care and attention, and each year it compounds to a higher potential yield as the early roots develop.

Success is dependent upon choosing cultivars that match your USDA zone. Coastal gardeners enjoy growing the fuzzy cultivar, called Hayward, while gardeners in transitional zones will likely enjoy Ken's Red. I have grown hardy kiwis from Vermont to Texas by prioritizing chill hours and frost dates, rather than trends and varieties. Testing the soil will also prevent you from growing the wrong type of kiwi.

For new growers, cold-hardy Issai is the best choice because its self-fertile pollination is very easy. I recommend new growers to plant in containers to facilitate root control. Once you reach your ten-year point, you can start to experiment with specialty types. The Kolomikta that I have now thrives after surviving -30°F weather with light protection for 10 years.

Cultivating kiwifruit is a long game.You will want to keep track of the growth phases in a journal so you know when sprouts and buds swell and bloom for the first time; also consider sharing cuttings with neighbors or friends as a way to diversify your genetic stock.Also, in some required planning a single vine can be turned into a legacy fruit orchard.