Asparagus
Garden Asparagus, Sparrow Grass, Asparagus officinalis, Asparagus
Long-term investment — plant crowns (1-year-old roots) in spring, 8" deep in trenches. Do not harvest at all in year 1; harvest sparingly in year 2. Full harvests begin year 3 and the bed can produce for 20–30 years. Well-drained soil is critical; asparagus crowns rot in waterlogged beds. Fronds must be allowed to fully grow after harvest to rebuild crown energy. Weed control is essential during establishment.
- Germination
- 14–21 days
- Spacing
- 45 cm
When to plant asparagus
Plant 2–6 weeks before your last spring frost.
Dashed line: typical last spring frost in zone 7 (Apr 5). Zone dates are averages; most of the UK is zone 8–9, central Europe 6–7 and the Baltics and Scandinavia 4–6. In the app, Tomatograph uses your garden's own frost dates.
How to grow asparagus
- 1
Plant crowns
Plant one-year-old crowns in early spring, as soon as the soil can be worked. Dig a trench 20 cm deep, set crowns 45 cm apart and cover gradually as shoots grow.
- 2
Be patient
Don't harvest at all in the first year and only lightly in the second. A well-made bed then crops for 20 years or more.
- 3
Look after the bed
Free-draining soil is essential; crowns rot in waterlogged ground. Keep weeds down and let the ferny foliage grow after harvest to feed the crowns.
- 4
Harvest
From year three, cut spears at soil level when 15–20 cm tall, for about six weeks in spring.
Growing conditions
Light
Full sun
Water
Medium water
Temperature
-20–32 °C
Frost tolerance
Frost-hardy — tolerates frost
Days to maturity
730–1095 days
Ideal soil pH
7–7.5
How Tomatograph watches your asparagus
Tomatograph checks your local forecast every morning and only speaks up when one of these applies to your garden.
- First frost within 14 daysReminder to mulch the roots before winter.
- 3 days at 35 °C or aboveHeat-wave alert while plants are flowering or fruiting: shade and water early.
- Humidity above 80% for 48 hoursCheck for fusarium crown rot, which thrives in those conditions.
- Within a week of maturityHarvest-window reminder based on when you planted.
Asparagus questions
- When should I plant asparagus?
- Plant 2–6 weeks before your last spring frost.
- How far apart should I plant asparagus?
- Allow 45 cm between plants.
- What grows well with asparagus?
- Good neighbours include tomato, parsley, basil.
Growing guide written by Tomatograph. Planting figures from openplantdb (CC0 1.0). Zone frost dates are averages from openplantdb (CC0 1.0).