Kiwi
Can I Grow Issai (Hardy Kiwi)?
Issai is the self-fertile hardy kiwi that makes kiwi growing possible in cold climates — grape-sized, smooth-skinned fruits you eat whole like candy. No peeling needed, no male vine required, and it survives winters down to -25°F.
Growing Requirements
Chill Hours
100
Hardiness Zones
6-7-8-9-10
Harvest
September to October
Results
Enter your zip code to see if Issai (Hardy Kiwi) will thrive in your area.
You checked if it'll grow. Now make sure you remember what happens when it does.
Pruning dates, harvests, spray schedules, what worked. The gardeners who get the most from their trees are the ones who kept records.
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About Issai (Hardy Kiwi)
Issai is the self-fertile hardy kiwi that makes kiwi growing possible in cold climates — grape-sized, smooth-skinned fruits you eat whole like candy. No peeling needed, no male vine required, and it survives winters down to -25°F.
Issai (Hardy Kiwi) requires 100 chill hours — the number of hours between 32°F and 45°F during winter dormancy. Without enough chill, the tree may fail to flower properly or produce poor fruit.
⚠️ Common Challenges
Less vigorous than other hardy kiwis; late spring frosts can kill emerging shoots; needs strong trellis support.
❌ Common Misconception
Will Issai (Hardy Kiwi) produce more fruit in colder climates?
Not necessarily. Issai (Hardy Kiwi) only needs 100 chill hours. Planting in very cold zones (5 or colder) risks winter damage without improving fruit production. The ideal zones are 6-10 where the tree gets enough chill without excessive cold stress.
If you plant it, write it down.
Variety, rootstock, planting date — and every pruning and harvest after that. Future you will thank you.
Free for up to 30 plants. No card needed.
Other Kiwi Varieties
Chill hour data from ERA5 reanalysis (Copernicus/ECMWF). Variety information compiled from university extension services.