Growing Asparagus From Crowns
Asparagus is a wonderful crop to grow in the home garden. This plant thrives in temperate and cool climates but performs in subtropical regions of Australia too. Perennial in nature they provide delicious shoots for you year after year, in some cases for multiple decades! This is due to their amazing root systems that store energy underground after the growing season. With the right care, they will be sure to flourish in your garden.
Why grow asparagus from crowns?
Crowns are a part of the plant with an attached root system. Mr Fothergill’s supplies these as two year old bare rooted crowns in the summer produce season, for planting in winter to early spring.
The main advantage of growing from crowns compared to seeds is it will establish in your garden much faster as asparagus take quite some time to get going. This is important not only for the size of the asparagus spears but the quantity you can harvest over the picking season.
How to grow asparagus from crowns
Planting and Soil Preparation
Asparagus enjoy full sun in a well-dug deep soil, with plenty of organic matter too. A soil pH of roughly 6.5 to 7 is ideal. If your soil is more acidic, improve it with an alkalising product such as wood ash (potash) or horticultural lime to raise the soil pH. Only apply a soil amendment if you have tested your soil with an at home pH kit as it may not require any treatment at all.
Prepare your garden bed with a garden fork to a generous depth of at least 30 cm mixing in aged cow or poultry manure as you go. Better yet, try out the trench method for larger plantings or in heavy clay soils.
To grow asparagus in trenches dig a long channel approximately 40cm deep and 20cm wide. Make sure it is long enough to space each of your crowns 20-30cm apart. In the bottom of your channel lay good quality garden compost and aged manure and mix it about with some of the original soil. This will improve the drainage and fertility deeper in the soil where the roots will spread. Mound up the compost mix in the trench toward the middle, leaving about 10-15cm from the top to your surrounding soil level.
Before planting the crown, soak it in some plain water or compost tea for an hour or so, to kickstart the rehydration process. After soaking pop the crown on the top of this soil mound in the trench, allowing the roots to spread out around the sides. Backfill with more soil covering the top of the crown to a depth of about 10cm.
Now that your crowns are planted and ready to roll, the waiting game begins. It is advisable to mulch between rows and beds at this time, to keep down the weeds. Ensure that any mulch around the young crown is not too thick and heavy to where shoots will struggle to push through, sugarcane mulch is great for this. Remove weeds and grass as they appear, as they will be stealing nutrients and moisture away from your asparagus crop.
Asparagus are hardy once established though it is important to keep an eye on the soil moisture, particularly in the spring and summer. In dry climates, you may need to water more deeply on a regular basis, depending on if the soil is moist when you dig down a few centimetres.
In the first year of planting give your crop a light top dress of balanced feed in the spring, as remember we put in all that compost underneath in the winter. Skip harvesting for the first season or two with crowns and allow them to put on lots of lush leafy growth. This energy from the leaves will redirect into the crown over winter, which means better quality harvests the following year.
Once the leaves and stems die down in the winter and turn dry and yellow remove them at ground level leaving room for the new growth in spring. This will open up your garden bed again, which will allow you to remove any weeds or grass that has snuck in. Apply a thin layer of compost/ aged manure and mulch over the top of the now dormant crowns in preparation for spring.
- When you have patiently waited a season or two for your crown to mature nicely you can start with some light harvests on the new season spears that push through the mulch. Pick these regularly over a week or two to begin with, and the following season extend the harvest timeframe by another couple of weeks and so on and so forth.
- You want to harvest the spears and catch them before the buds begin to open out and they are still juicy and young. Once open they will become fibrous so are not too pleasant to eat.
- With any well-established asparagus crop, you don’t want to exceed harvest time by more than a couple of months each growing season as this will deplete your harvests for the following year and can really set back the plants.
- After your set picking season ensure you allow the rest of the spears to mature into adult leaves, these will replenish the energy store in your crowns at the end of the season.
- Avoid walking over your beds or trench planting lines where the crowns are contained especially in the lead-up to spring. Any foot traffic or compaction can break the developing spears underground or make it harder for them to push through the soil.
- For white asparagus that have a milder flavour try excluding light from your spears before they break through the soil with tubs or tarps. The lack of sunlight will prevent the crop from turning green!
Where to buy asparagus crowns in Australia?
Mr Fothergill's stocks asparagus crowns as part of our Summer Produce bulb range. Summer produce is available seasonally between June and September.