Nut · Juglandaceae
When to plant walnuts
A forest tree that will eventually shade a small garden entirely, and whose roots suppress the growth of many other plants around it. Plant it where it can stay.
First worthwhile crop
Year 6
After planting, not after sowing.
Hardy in USDA zones
5a to 9a
Winter cold sets the limit here, not the calendar.
Frost tolerance
Very hardy
How much cold the plant itself will take.
Those weeks become real dates once you name a place.
Timing, in frost-relative terms
Nothing about a standing crop is sown to a calendar. Once planted, walnuts stay in the ground for years, so the question is not when to sow but whether your winter is survivable and your planting window is open. Both answers come from your frost dates.
- Expect a first worthwhile crop in year 6 after planting.
- Needs roughly 700 chill hours below 7.2°C (45°F)45°F (7.2°C) over winter to set fruit, which rules out the warmest climates.
- Hardy in USDA zones 5a–9a.
Getting the timing right
Plant dormant. Walnut leafs out late, which conveniently protects it from spring frost, but the nuts then need a long warm autumn to fill. Grafted named varieties bear years earlier than a seedling and are worth the extra cost.
Frost tolerance
The dormant tree is hardy to about -25C. The late leafing means frost damage to new growth is rare, which is unusual among nut trees.
Classified as very-hardy.