How to Grow Asparagus
If you love asparagus and want to grow your own, plant right away, as it will be several years before you are harvesting enough spears to make a dinner.
Starting asparagus roots from seeds is a true lesson in patience. It will be 5 years from sowing till you are harvesting a few spears, and several more on top of that till you have enough for a meal.
Planting from good sized roots right from the start will have you enjoying an asparagus dinner in just a couple of years. A few spears next year and then progressively more each year thereafter.
I am growing both Sweet Purple and Jersey Knight asparagus in the same bed. The purple is touted to be sweeter and less string, while the green ones are said to be the best on the market for production. I like them both equally, they taste great, grow and produce well.
Ideally, when you go to purchase your roots, choose one of the newer varieties ( Jersey Knights or Jerseys Giant, or any of the purple varieties), as they will produce better than the older ones, like Mary Washington.
When you buy those roots, you may be picking them up in bulk or, most likely, in a little mesh bag from a box store or nursery. For the best results, look for nice, plump, fleshy roots with perhaps a bit of white, new growth showing at the top. If the roots are dry and skinny, chances are that they have dried out and died in storage, do not waste your time or money on those.
Decide where best to plant your asparagus bed. Remember, this is a perennial planting and the it resents being moved, plan for the long haul.
You can plant about 6 weeks before the last frost date, so in my neck of the woods, this means mid-March. If you are unable to plant right away, store them in a cool, dark space until you can get to planting. If the ground is covered in snow or is too wet to work in, you may be better off to pop them into pots for a few weeks time until you are able to get them settled in their forever home.
Give them a good soak…. While you are digging the trenches for your asparagus, to rehydrate the roots, pop them into some warm water with a splash of liquid seaweed in it. Soak for 30 to 90 minutes, or as long as it takes to get the trenches ready.
Loosen up the soil and make sure the area is weed free, asparagus will not compete well for nutrients. It is a heavy feeder and will be in that spot for a long time, so you really want to get it off to a great start. Amend your soil with a good amount of manure or compost, and perhaps some organic slow release fertiliser, as well. I like Gaia Green 4-4-4 , a Canadian product from right here in BC, but you can use any kind that you like best, or even build your own organic fertiliser from the bulk section of the nursery.
Make a trench that is 8 inches wide and deep. Build a small mound down the centre of your trench so that your trench is shaped like a ‘w’.
Place the crown of the asparagus on top of the small mound, with the roots going down the sides. Ensure that the soil is loose and friable where so that the roots can spread deep into the bed.
The crown should be about 4 inches below the surface when you fill the trench back up with soil.
Plant the roots 12 to 24 inches apart in the trenches and the rows about 2 feet apart. In my 4’ wide raised beds, I was able to plant two rows of asparagus, a bit more than 1.5’ apart.
Water the roots with the liquid seaweed water they were soaking in, fill in the trenches, water the bed.
As a general guide, 8 to 12 roots should be enough to feed a family of 4 with asparagus. Some guides will say that you need as many as two dozen roots! Perhaps it depends on how much asparagus you want to eat and how much you have room for.
I planted 12 roots in this bed and then added more a couple of years later, for a total of 16 plants. We are just a family of 2 here at home, however, we also have adult kids with significant others that we feed regularly. Hmm, perhaps I need to plant some more ….
Never harvest all of the stalks each year. Leave some to grow into tall fronds which soak up the sun and nutrients that make your asparagus grow bigger and better.
In late summer, these fronds will start to yellow, chop them down and top dress your bed with some manure or compost, and perhaps a bit more slow release, organic fertiliser, as well.