I have been doing a lot of research on growing asparagus and I just wanted to share what I've been learning. I use my blog as my resource for information, so it will be helpful for me to have the info here. Plus, I hope others may find it useful at one point or another, as well.
Last year, I planted 25 crowns of Purple Passion Asparagus in our garden. We love asparagus and tend to eat it every other day when its in season. I want to eventually have enough to not only eat fresh as often as we like, but also to blanch and freeze so that we can enjoy our own home-grown asparagus in the fall and winter months.
Find a Source
The first step in growing asparagus is to find a good source for crowns. I ordered my crowns from Fedco. You'll need to decide what variety you are interested in. There are many to choose from. I chose an all male variety, as I have read they are most productive since they're not wasting energy producing seeds like females.
Plant asparagus during the dormant period - for me that meant early spring. To plant the crowns, you need to dig a trench about a foot deep and about a foot wide. Make sure you also amend your soil, if necessary. Remember, asparagus is a perennial, so you'll want a good, nourishing soil to grow it in. You should add some good compost as you are planting the crowns, too. I also added some manure as I was planting mine.
You will want to space the crowns about 18 inches apart and then cover with a few inches of soil. As your plants sprout and grow, you should fill in the trench with more soil so as to provide a good, strong growing base.
What to Plant (and Not to Plant) Near Asparagus
Good companions for asparagus are: basil, parsley, and tomatoes. Bad companions for asparagus are: onions, chives, garlic, and leeks.
I have read mixed things about when to take your first harvest after planting crowns. Definitely do not harvest any asparagus spears the first year you plant the crowns. Just let them grow. I think asparagus is actually quite pretty. I never realized how pretty the asparagus ferns could be. The ferns get quite tall - like 5 or 6 feet - so make sure you also take this into consideration when you are planting your crowns.
Some sources say that you should not harvest the second year, either. And some sources recommend leaving them alone a third year, even. Many sources say you can harvest the second year, but only a light harvest. I've decided not to harvest mine yet this year. I will harvest some next year, but only a light harvest. I figure I will harvest 2 or 3 stalks per crown next year and leave the rest to grow into ferns, as I want my crowns to really get established and growing strong.
Harvest asparagus when the spears are between 6 and 8 inches long and the tips are still tightly closed. Cut off the spears just below the surface of the soil using a sharp trowel/shovel. You'll want to leave the very thin spears to grow into ferns and nourish your roots.
You can extend the harvest of your asparagus by allowing 3 or 4 spears per crown to grow into ferns. By doing this, your crowns are always producing enough energy and food via photosynthesis. This will extend your harvest by weeks. Once the diameter an the spears is thinner than a pencil, its time to stop harvesting and let them grow into ferns.
After 4 years of good growth, your plants should be producing strong for about 8 weeks.
Diseases and Pests
Asparagus is susceptible to asparagus rust, which looks like orange/yellow spots on the foliage. Make sure you are selecting varieties that are resistant.
Another common issue are asparagus beetles. They usually appear later in the season and eat the ferns. This will weaken the crowns. Hand-pick off the beetles and squash them, or try applying soap spray directly on the beetles. After the first frost, remove the dead ferns and destroy so as to eliminate a place for the beetles to over-winter. A good defense against asparagus beetles is to plant tomatoes, basil, and parsley next to your asparagus plants. They will deter one another's pests.
To make a soap spray, mix 1 teaspoon Dr. Bronners soap in 1 quart of water. Shake it up and spray.
Cutting The Ferns As You Prepare For Winter
Asparagus fronds should not be cut until very late in the fall. By this time, the ferns should be dry and brittle. You want to leave the ferns as long as possible, as the roots need the top growth to enable them to make spears the following spring.
After you cut the ferns back, you will want to spread a layer of compost or manure over the asparagus bed. Then top with a thick layer of straw.
This post is shared at: Real Food Wednesday at Kelly the Kitchen Kop