Growing walnut
nut
Pollination
Self-fertile, but male and female flowers on one tree often open at different times - a second variety greatly steadies the crop.
Growing it
Zones 5-9. A very large, long-lived tree. Its roots and leaves release juglone, which stunts or kills tomatoes, apples, blueberries and many other plants nearby.
Where walnut grows best
Hardy in zones 5-9, and it needs enough winter cold - about 400-1500 chill hours - to flower and fruit well. Combining the two:
Good fit across most of: Alabama, Arkansas, Colorado, Connecticut, Delaware, District of Columbia, Georgia, Idaho, Illinois, Indiana, Kansas, Kentucky, Maryland, Massachusetts, Michigan, Mississippi, Missouri, New Jersey, North Carolina, Ohio, Oklahoma, Pennsylvania, Rhode Island, South Carolina, Tennessee, Utah, Virginia, West Virginia. Also parts of Alaska, Arizona, California, Florida, Iowa, Louisiana, Maine, Minnesota, Montana, Nebraska, Nevada, New Hampshire, New Mexico, New York, Oregon, South Dakota, Texas, Vermont, Washington, Wisconsin, Wyoming.
Will you get enough chill?
Walnut (English / Persian) needs roughly 400–1500 hours between 32 and 45 °F over winter to break dormancy evenly. Check your area with the chill hours calculator. Low-chill breeding has pushed many varieties well below the figure here, so read the plant tag.
Questions gardeners ask
What zone does walnut grow in?
Walnut (English / Persian) grows in USDA hardiness zones 5-9. In the warmest of those (zone 9), winters may be too mild to give the chill it needs, so choose low-chill varieties there.
How many chill hours does walnut need?
Roughly 400-1500 hours between 32 and 45°F over winter, depending on the variety. Low-chill varieties need less - check the plant tag, and estimate your own area with the chill hours calculator.
Does walnut need a pollinator?
Partly self-fertile — crops much better with a partner. Self-fertile, but male and female flowers on one tree often open at different times - a second variety greatly steadies the crop.
Which states can grow walnut?
Walnut (English / Persian) suits most of Alabama, Arkansas, Colorado, Connecticut, Delaware, District of Columbia, Georgia, Idaho, Illinois, Indiana, Kansas, Kentucky and 16 more, and parts of 21 other states where the right zones occur. Your own zone and chill hours matter more than the state.
Chill and pollination are given at the fruit-type level; specific cultivars can differ. Values are typical ranges for home-garden planning.