How to grow Walnut in the UK
Juglans regia
Walnut (Juglans regia) is a fruit that grows well in UK gardens. Massive tree eventually — 15m+. Allelopathic roots kill plants beneath. For large gardens only. This guide covers when and how to sow Walnut, the soil and position it likes, watering and feeding, companion planting, and when to harvest.
When to sow & grow Walnut
Sowing and harvest window through the year (UK):
Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep Harvest | Oct Harvest | Nov Plant | Dec |
Soil, position & care
- Soil
- Deep, fertile, well-drained soil
- Soil pH
- 6.0–7.0
- Position
- Sun and shelter for good pollination
- Sowing depth
- Plant to the original soil mark; stake bare-root trees
- Spacing
- Large tree — allow 12 m+
- Sowing
- Plant a young grafted tree; very slow to crop (years)
- Growing
- Water well for the first 3 years; mulch and feed in spring
- Harvest & upkeep
- Prune only in late summer (bleeds badly otherwise); allelopathic — keep veg away from the roots
- Watch for
- Squirrels, walnut blight
Companion planting for Walnut
Keep apart from:
Walnut roots release juglone, which poisons many plants — keep tomatoes, potatoes and apples well clear.
Add Walnut to your free 12-month plan and get watering & sowing reminders — no sign-up needed.
Walnut FAQs
What should you not plant near Walnut?
Keep Walnut away from Apple, Potato, Beef Tomato, Cherry Tomato, which can compete with it or share pests and diseases.
How much sun does Walnut need?
Walnut prefers full sun (6+ hrs direct).
When is Walnut ready to harvest?
Walnut is typically ready to harvest in September, October in the UK.
Is Walnut easy to grow?
Challenging. Massive tree eventually — 15m+. Allelopathic roots kill plants beneath. For large gardens only.