Jul 24, 2013

Growing Kiwi - Even in Cold Climates!

My Arctic Kiwi vine in May.
Both here and on Facebook, I've mentioned my kiwi vines. This has inspired a lot of interest. "You must live where it's tropical!" some people say. Others are curious why the fruit from my vines aren't hairy. Others want all the details on how to grow their own kiwi. Because yes, it's true: You can grow kiwi, even if you live in a cold climate.

Choosing the Right Type of Kiwi
Here's the secret: I'm not growing the type of kiwi you buy in the grocery store. I'm growing a different variety that tastes just the same, but doesn't require a tropical environment. The type you buy in the store is Fuzzy Kiwi (Actinidia deliciosa). It is hardy to 0 degrees F. and requires a lot of water.

Then there's Hardy Kiwi (Actinidia arguta) and Arctic Beauty Kiwi (Actinidia kolomikta), which are hardy to minus 25 degrees F. or below (down to zone 4). Both these hardy plants produce smaller fruit than Fuzzy Kiwi; most are about the size of a large grape. And the fruit isn't fuzzy. I have Arctic Beauty, which has beautiful pink/white/green variegated leaves (which don't appear until the plant is 2 or 3 years old), is more compact, and has more flavorful fruit. (They taste just like a really good, fresh, ripe Fuzzy Kiwi.)

Both Hardy and Artic Kiwi require a male and female plant in order to produce fruit. (Buy at least one male plant for every 9 female plants.)

Where can you purchase Hardy or Arctic Kiwi? If you're fortunate, a local nursery will have year old plants for you. Otherwise, you can order plants online from Territorial Seed or One Green World. I don't recommend trying to grow them from seed; I know from both research and experience it's not very easy to do so.
Arctic Kiwi fruit when it first appears.

Choosing the Site
Hardy and Artic Kiwi like full sun to part shade - at least 1/2 a day of sun. (My vines are in part shade.) The vines can grow to 40 feet, so you'll need a good support system for them. I just used some metal arches I originally bought for my wedding, but it would be better to have a wooden or sturdier metal support. It's a good idea not to plant the vines near other trees or fences/walls you don't want the plant to climb, since this will lead to constant pruning - which is not only a pain, but can lead to less fruiting because you have to cut off flowering vines.

Kiwi like soil that's between 5.5 and 7.0 pH; they aren't very picky about the soil, as long as it drains pretty well. I grow mine in large pots (about 22 inches across - the largest I could find at the time) filled with potting soil - although the roots have mostly taken up these pots and I may need to transplant them someday soon.

It's also best to plan ahead and make sure the vines have at least 150 days without frost, once they are planted. This gives them time to acclimate to their new home and become fully hardened against frost.

Be sure to mulch around the base of the plant, but don't let the mulch touch the trunks.

Most sources recommend growing kiwi about 10 feet apart. I didn't have that luxury and grow my potted vines right next to each other.

Caring for Kiwi
The fruit looks like this while it is maturing - and once it is ripe.

Many sources recommend pruning kiwi throughout the growing season. I never have. Cornell University recommends: "Two or three times during summer, cut non-flowering laterals back to the outside wire on the trellis. Trim flowering shoots back to 4 to 6 leaves beyond the last flower." 

I have also never pruned during the dormant season (winter), but Cornell says: "In the dormant season, remove canes that fruited last season, as well as dead, diseased or tangled cane. Keep the best one-year-old lateral canes that haven't fruited, spaced about a foot apart along the arms. Trim them back to about eight buds."

Most sources also recommend that if you live in an area that gets snow, you should wrap the trunks of the vines with cloth, to prevent cracking. We get very little snow, so this has been unnecessary for us.

If you grow your vines in full sun, they are more likely to bloom early. Then, if a frost comes, the flowers are not likely to bear fruit. So if temperatures will be 31 degrees F. or below after blooming, be sure to sprinkle your plants with water at night. This protects the foliage, keeping it at 32 degrees or above. (Ice will appear on the leaves.) You may also protect the vines by covering them with a blanket.

Don't fertilize your kiwi the year it's planted. In the second spring, sprinkle about 2 oz. of 10-10-10 fertilizer around each plant. Every year after that, increase the amount by 2 oz. until you are giving each plant 8 oz. - the maximum amount you should give them.

Yummy! Ripe Arctic Kiwi.
Most sources say it takes between 3 and 5 years for kiwi to produce it's first crop. My vines produced for the first time this year - 2 years (3 seasons) after I planted them. They were 1 year old plants. I harvested about 1 lb. of fruit from one female plant. In future years, I can expect about 5 lbs. from that plant.

The fruit comes on reddish-green, then turns completely green and stays that color once ripe. You'll be able to tell if the fruit is ripe by touching it: Unripe fruit is hard; ripe fruit is softer. Also, if you cut open a fruit, it will have black seeds if it's ripe.

I found that not all my vine's fruit was ripe at once - but that can be a good thing. Ripe kiwi don't store very well. You can pick not-quite-ripe fruit and store it (unwashed) in a Ziplock bag in the refrigerator, and it should last quite a long while. Some sources say months.

You may also dehydrate kiwi (I would slice Hardy or Artic kiwi in half first), or make wine from from the fruit.

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