This may seem like the wrong time of year to think of asparagus; Harvest time is over and the crowns are likely sold out. Now is a good time to plan and prepare the bed that you will plant next year.
Asparagus can be made from seeds or bought as a starting plant, but I prefer to grow it from crowns. Crowns are the heart of the plant and grow deep underground. This depth varies with soil texture and other growing conditions.
Start the asparagus project next year by keeping your future bed fallow. This can be done with chemicals or by cultivating with a rotary tiller every two to three weeks. Rototilling offers you the opportunity to increase fertility with 10-10-10 fertilizers, animal manure or compost. Cultivation discourages quacks, kills annual weeds, and encourages the germination of multi-annual weeds, which will be killed in the next cultivation. Covering with a tarpaulin or a ground cover prevents new seeds from being blown in and removes light from existing weeds.
Asparagus prefers a soil pH value of 6.5 to 7. It tolerates soil textures from sandy to loamy. Organic material is always good.
Asparagus can be grown according to the principles of hill culture by burying woody material under the bed. It can be grown in raised beds. When the raised beds are deep enough, you can work the woody materials into the bottom of the raised bed.
The University of Minnesota recommends several varieties of asparagus, including Millennium, Jersey, Washington, Viking, and Purple Passion. Some nurseries offer all male plants. Male plants spend less time developing seeds and are expected to produce more each year. They live longer too. Female plants produce larger diameter spears. They produce red, inedible berries that lead to baby plants in the bed. Uniform spears of one sex are easier to cook.
In the spring, plant the crowns in the ground of 20-inch trenches three or more feet apart. The plants spread naturally. Inside the trench, place the crowns a foot apart in the row. Cover with an inch of soil. As the plants get taller and stronger, add soil until the row is level.
The university recommends harvesting two years after planting crowns and three years after planting seeds. I think that’s optimistic. I usually wait three years and choose for a short period of time. Choose asparagus when it looks ready to eat with a height of around 8 inches. Choose carefully. When you stop, let the whole bed fade into ferns. Mid to late June is a good time to stop choosing a full-blown bed.
Don’t neglect the asparagus off-season when producing next year’s crop. Add more fertilizer and organic matter and keep it watered. One inch per week is recommended and more on sandy soils.
If you have old planting that grew up in weeds and grass, asparagus is a great way to save it. In early spring, after the grass has turned green and before the asparagus sprouts, you can apply a weed control chemical or cultivate 10 cm deeper with a rotary tiller and clean the bed immediately. After a year of weed-free growth, the bed should be productive again.
These local gardening supplies are available every week during the gardening season, but year-round gardening information can be found by clicking Yard and Garden on the University of Minnesota Extension website, www.extension.umn.edu, or by clicking. visit our Facebook page at www.facebook.com/Beltramicountymastergardeners.
Local master gardeners answer questions via voicemail. Call (218) 444-7916 leaving your name, number and question.