How To Grow Your Own Asparagus

Farm Director Pam Jahnke uses this episode of AgriCultured to talk with Ed Bures, a UW – Madison Agriculture Professor and owner of Bures Berry Patch, about how to grow your own asparagus at home.

Asparagus…What is it?

Asparagus is a long-term perennial plant that grows very aggressively. It can survive in the wild and in areas along ditches, places it had been planted before, or where seeds have been previously dropped. Long-term perennial asparagus can live and produce for well over fifteen years.

Garden asparagus has developed a lot of different varieties. Some have different flavors, tenderness and more long-term productive lives. Millennial Asparagus is one of the most widely populated in the Midwest, especially in Michigan. Michigan grows the majority of the asparagus in the Midwest and is where most growers learn their techniques.

How Much Space Do I Need To Grow Asparagus?

Asparagus is a plant that needs a lot of open space. You want to be able to plant the asparagus crowns and allow them space to grow about two to three feet in size over a twenty year period.

Asparagus needs a lot of time and space to be able to grow properly. This being said, asparagus may not be the right choice for a home garden with a small, limited space.

Planting Asparagus

When you plant asparagus plants in your garden or at a commercial farm, you get what are called plant or root crowns that are usually about two years old. You dig a trench of about eight to ten inches deep, and bury the root crowns in the trench. They have to be planted very deep, because they will be there for about twenty to thirty years after planting.

The root crowns should continually expand underground, which allows more shoots to grow up from the ground as it expands. Being so deep in the ground allows the asparagus plant to get moisture, and protects it from root frost heaves and other problems faced by short-term perennials or annual plants.

Fertilizing and Nutrition

Along with planting the asparagus root crowns deep in the trench, you want to provide the plant with Phosphorus. Phosphorus is an extremely important nutrient for root growth. To get the asparagus growing and expanding early, get Phosphorus to put on the crowns while planting.

Putting Phosphorus directly on the plant’s roots will not harm it, as asparagus is very tolerant to the Phosphorus fertilizer, and it’s important to provide it for the plant to produce more abundantly.

How Long Until the Shoot Comes Through the Surface?

Being buried eight to ten inches below the ground’s surface, the soil type has a big impact on how long it will be until you see your asparagus spears come through the soil’s surface.

Heavy soils take a lot longer to warm up in the spring than lighter, thinner soils do. Typically, if your soil is sandy in southern Wisconsin, you might see spears mid to late April. In comparison, locations with heavier soil may not see spears until the first week of May.

Another factor that makes a big difference is the spring weather. If you get warm, early spring rains, the warmth from the water will bring the cold and frost out of the ground and get the crowns growing quicker.

How Do You Know When To Harvest?

Good and ripe asparagus stems should be about the width of a Sharpie marker in diameter. When the asparagus is about this size, it’s typically time to harvest the spears. When you start to see asparagus that is a pencil diameter or less, that’s normally a sign to stop picking for the year.

Following this measurement system for picking spears helps the plant regenerate, and you should also continually fertilize the plants so they develop a strong root crown.

Like strawberry plants, asparagus plants need full sun in order to be productive. Although it is an aggressive growing plant, it still needs the right nutrients and care to grow properly.

For more tips and information on growing produce, check out Blain’s Farm & Fleet’s Hobby Farming and Gardening blogs.