Grow Asparagus from Seed: A Beginner's Guide
You can grow asparagus (Asparagus officinalis) from seed by soaking it for 24 hours, sowing it 1 to 2 cm deep indoors from February to April at 21 to 25°C, and growing the seedlings on in pots for a year before planting them out 30 to 45 cm apart the following spring. Start cutting spears lightly in the third spring after planting; a well-made bed then crops every April to June for 15 to 20 years.
Short on time? Growing from seed adds a year or two before your first spears. Our potted asparagus crowns skip the seedling stage and get your bed cropping sooner.
Asparagus (Asparagus officinalis) is a true perennial vegetable, capable of producing tender spears from the same bed for 15 to 20 years once established, making it a fantastic long-term investment for any food forest or permaculture garden. Growing from seed takes patience, but it's far cheaper than buying crowns and lets you raise a larger, more resilient bed.
This guide will walk you through how to germinate asparagus seeds, care for young plants, and get a bed established for years of spring harvests.
Asparagus Quick Facts
Latin name: Asparagus officinalis
Sow: February to April indoors, after soaking seed for 24 hours
Germination: 2 to 8 weeks at 21 to 25°C
Plant out: the spring after sowing, 30 to 45 cm apart, rows 45 cm apart
Soil: deep, fertile, free-draining, weed-free
Position: full sun
First harvest: lightly in the third spring after planting
Harvest season: mid-April to mid-June
Bed lifespan: 15 to 20 years
Main problems: asparagus beetle, slugs, perennial weeds, waterlogging
Step 1: Sow Asparagus Seeds
Asparagus seeds benefit from a head start indoors, as they need warmth to germinate reliably.
Soak seeds in warm water for 24 to 48 hours before sowing to soften the seed coat and speed up germination.
Sow seeds around 1 to 2 cm deep in modules or small pots filled with a peat-free seed compost.
Keep at a warm, consistent temperature of around 21 to 25°C; a heated propagator speeds things along considerably.
Step 2: Germination and Early Growth
Asparagus is notoriously slow to germinate, so don't be discouraged if nothing happens for a few weeks.
Germination typically takes two to eight weeks, so keep compost consistently moist throughout and be patient.
Once seedlings emerge, move them to a bright windowsill or greenhouse with plenty of light to prevent leggy growth.
Thin to the strongest seedling per module if more than one germinates in the same cell.
Step 3: Grow On in the First Year
Asparagus seedlings need a full growing season to bulk up before they're ready for the garden.
Pot on into larger 1-litre pots once roots fill their initial containers, using a rich, well-draining compost.
Grow on outdoors in a sheltered spot over summer, watering regularly and feeding fortnightly with a diluted organic liquid feed.
Protect from frost over their first winter, keeping pots in a cold frame or unheated greenhouse.
Step 4: Prepare the Permanent Bed
Because asparagus stays in place for well over a decade, bed preparation is one of the most important steps.
Choose a sunny, open spot with deep, fertile, well-draining soil, as asparagus dislikes waterlogged conditions and heavy shade.
Dig in generous amounts of well-rotted organic compost or manure the autumn before planting to enrich the soil deeply.
Clear the bed thoroughly of perennial weeds beforehand, since asparagus is difficult to weed around once established.
Step 5: Plant Out
Young asparagus plants (called crowns once dormant, or simply seedlings if planted while actively growing) are typically planted out in their second spring.
Dig a trench about 30 cm wide and 20 cm deep, make a low ridge along the bottom, and set plants 30 to 45 cm apart with their roots spread over the ridge. Cover with 5 to 8 cm of soil, then gradually fill the trench as shoots grow.
Space rows at least 45 cm apart to give plants room to spread their fern-like foliage.
Water in well and mulch with organic compost to suppress weeds and retain moisture.
Step 6: Ongoing Care and First Harvests
Resist the urge to harvest early: Don't cut any spears in the first two years after planting, this lets the plant build a strong root system for future harvests.
Feeding: Top-dress with organic compost each spring and autumn to keep beds productive for decades.
Weeding: Keep beds weed-free by hand, as asparagus roots are shallow and easily damaged by hoeing. Watch for asparagus beetle from May: pick off the black-and-yellow adults and grubs, and clear old foliage in autumn.
First harvest: From the third spring after planting, cut spears when they are 15 to 20 cm tall for a short 4 to 6 week window, stopping by mid-June, then let remaining growth develop into ferny foliage that feeds the roots for next year's crop.
FAQ: Growing Asparagus from Seed
How long does asparagus take to grow from seed?
Asparagus is sown in spring, grown on for a year, then planted out. You can take a light harvest in the third spring after planting, so allow about four years from seed to your first proper crop.
Is it better to grow asparagus from seed or crowns?
Crowns save a year or two and are the quickest route to spears. Seed is much cheaper for a large bed, and lets you select the strongest plants, but needs more patience.
When is asparagus season in Ireland?
Home-grown asparagus is harvested from about mid-April to mid-June. Stop cutting by midsummer so the ferns can grow and feed the roots for next year.
Why should I not harvest asparagus in the first years?
The plant needs its ferny summer growth to build up its root system. Cutting spears too early weakens the crowns and shortens the life of the bed.
Should I grow male or female asparagus plants?
Male plants produce more and thicker spears because they don't put energy into berries. Seed-grown beds are a mix of both; you can remove the female plants, which carry red berries, once you can tell them apart.
Growing asparagus from seed is a genuine act of patience, but once established, a well-tended bed will reward you with fresh spears every spring for a generation.
Seed or Crowns? Getting Your Asparagus Bed Started
Asparagus from seed is cheap and rewarding, but it adds a year or two before your first spears. If you want to be cutting sooner, starting with established plants is the easier route.
At Earthling Plants we grow asparagus as potted crowns, ready to plant into a well-prepared bed. For more perennial vegetables that crop year after year, browse our perennial vegetables range.
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