Sow Asparagus, Reap (Harvest) for Decades
Although growing asparagus requires patience, it's worth it when you can harvest it for decades.
It takes up to three years to really get going (you can by pass the wait and buy asparagus crowns), this perennial plant will produce a bountiful harvest year after year for up to 30 years.
Additionally, the plant itself looks great, with a long feather-like top that turns a warm golden hue in the fall and makes a powerful appealing statement in your metal raised bed garden.
If you have asparagus seeds you can grow new plants with ease. It is best to start seeds inside or in the warmth of a greenhouse or in a metal raised garden bed.
Seeds require bright light and soil temperatures between 70-85 degrees for germination. I find it works best to soak the seeds for a couple of hours before planting as well.
- Fill 3.5-inch pots with sterile soil.
- Place 3 seeds on the surface of the soil in each pot.
- Cover the seeds with a thin layer of sifted sand.
- Bottom water all pots by placing in a pan with sides with water.
- Place on a heated table to be sure that the soil stays warm.
- Do not let pots dry out.
- Allow the seedlings to grow for three months before transplanting as long as all risk of frost has passed.
- Place transplants about 18 inches apart in rows that are 4 inches apart. For thinner spears, place them 8 to 10 inches apart and 4 inches deep. For thicker spears, place them 12-14 inches apart and 6-8 inches deep.
- Cover the seedlings with a light layer of soil as they grow.
- Provide one-inch of water each week.
- Remember, don’t harvest for three years – allow the plant to grow all summer and cut it back to 2 inches in the fall.
It is important to prepare your bed ahead of time so that you are ready when the crowns arrive.
Asparagus likes soil that is pH neutral and somewhat sandy and loose that drains well. I have had the best luck growing asparagus crowns in 2 x 8 raised beds.
My beds hold about 14 asparagus plants. If you are going to grow asparagus in with other vegetables, plant it on the north or west side of the garden so that it will not shade other vegetables.
- Work compost into the soil.
- Dig two 12-inch deep furrows in the raised bed.
- Put one cup organic fertilizer in each furrow.
- Mound up loose dirt into cone-shaped piles about 6 inches tall at the bottom of the furrow. Leave 18 inches between each cone.
- Put an asparagus crown on top of each dirt pile in the furrow. The roots should hang down over the dirt pile.
- Cover the crowns with about 1-inch of soil.
- Keep the soil moist but do not saturate.
- Keep weeds out of the bed.
- Add more soil as the asparagus continues to grow.
- Continue this process until the furrow are filled to ground level with the soil.
- Do not harvest for two years, let the spear grow into ferny plants and develop deep roots.
Plant asparagus seedlings near tomatoes. Asparagus repels nematodes that attack tomatoes and tomatoes repel asparagus beetles. Companion planting can really aid your growing efforts.
Harvest new asparagus crops for four weeks in year three and for six to eight weeks in year four and on.
Asparagus plants are either male or female. There are some varieties such as Jersey Knight and Jersey Giant that produce all male plants so that they are more productive. Choose an all-male variety if you want a bigger yield.
Apply mulch to suppress weeds.
Soak crowns in compost tea before planting to give them a burst of energy.
After harvest, allow plants to grow to replenish nutrients. Wait until the foliage has turned brown or yellow – usually in the fall. Cut down to 2 inches.
Fertilize established crowns in spring and fall using a rich organic fertilizer/compost containing things like fish, seaweed, kitchen scraps including bread dairy fruits and other vegetables.