Asparagus in Zone 7B — Southeast

Asparagus is a true treat in the Southeast garden, offering a flavor you just can't get from the grocery store. Nothing beats the taste of freshly harvested spears, grilled or roasted with a little olive oil. Plus, asparagus is a perennial, so once you get it established, you'll have a reliable crop year after year.

Our long growing season here in the Southeast gives asparagus plenty of time to mature. While we do have to contend with humidity and the occasional pest, proper site selection and good gardening practices will set you up for success during our 235-day season.

Asparagus is best started from 1-year-old crowns, which you can transplant outdoors in mid to late March here in the Southeast. Buying crowns saves you years of waiting compared to starting from seed; you'll be harvesting much sooner.

Before planting, harden off your crowns by gradually exposing them to outdoor conditions over about a week. This helps them adjust to the temperature swings and sunlight.

When you're ready to plant, space the crowns 18-24 inches apart in a well-prepared bed. Keep an eye on the weather; a late cold snap can sometimes surprise us in March, so be ready to cover your young plants if needed.

Asparagus needs moderate watering, especially during its first two years as it gets established. After that, it becomes fairly drought-tolerant thanks to its deep roots.

Here in the Southeast, our watering schedule depends on rainfall. During the hot and humid summer months, our afternoon thunderstorms usually provide a good soaking. Use the "finger test" – stick your finger about 2 inches into the soil near the plant. If it feels dry, it's time to water. Aim for about 1 inch of water per week, either from rain or irrigation.

Water at the base of the plants to avoid wetting the foliage, which can encourage fungal diseases in our humid climate. Yellowing or wilting spears can indicate underwatering, while soggy soil and rotting crowns are signs of overwatering. A layer of pine straw mulch helps retain moisture and suppress weeds, which is especially useful during our long summer.

Asparagus requires minimal pruning. The most important thing is to let the ferns grow and mature all summer long. These ferns are essential for feeding the crown and ensuring a good harvest next year.

Once the ferns have died back in late fall, or even early spring, you can cut them down to ground level. Just be sure to remove the dead foliage to prevent disease. Also, remember not to harvest spears for more than 8 weeks each season.

You can expect your first asparagus harvest about two years after planting crowns, typically starting in mid March and lasting through late November in our Southeast climate. Look for spears that are 6-8 inches tall with tight, unopened tips.

To harvest, snap the spear off at ground level. Be careful not to damage the surrounding spears or the crown. Continue harvesting regularly to encourage more spears to emerge.

As the season progresses, you'll notice the spears becoming thinner, about the width of a pencil. This is a sign to stop harvesting and let the remaining spears fern out to replenish the plant's energy reserves before our first frost in early November.

Here are some common problems you might encounter growing asparagus in the Southeast:

Asparagus Beetle

• What it looks like: Small, elongated beetles with colorful markings, or their dark larvae feeding on spears and ferns.
• What causes it: These beetles are attracted to asparagus plants and can quickly defoliate them, especially during our long growing season.
• How to fix/prevent it: Handpick beetles and larvae when you see them. Encourage beneficial insects. For heavy infestations, use neem oil, being mindful of pollinators.

Crown Rot from Poor Drainage

• What it looks like: Yellowing or wilting spears, stunted growth, and mushy, rotting crowns.
• What causes it: Our clay soil and wet-summer rainfall can lead to poor drainage, creating ideal conditions for fungal diseases that cause crown rot.
• How to fix/prevent it: Plant asparagus in raised beds or amend the soil with plenty of organic matter to improve drainage. Avoid overwatering, and ensure good air circulation.

Thin Spears from Over-Harvesting

• What it looks like: Spears that are consistently thin and spindly, even after the initial harvest.
• What causes it: Harvesting spears for too long or too frequently depletes the plant's energy reserves, resulting in weak growth.
• How to fix/prevent it: Limit your harvest to 8 weeks per season, and allow the ferns to grow and mature to replenish the crown's energy.

Southeast Specific Challenges: The hot, humid summers in the Southeast create a favorable environment for fungal diseases, so ensure good air circulation and avoid overhead watering. Our heavy clay soil can also lead to drainage problems, so amending the soil with organic matter is crucial. Japanese beetles can also be a nuisance, so monitor your plants and take action if needed.

Good companions for asparagus in the Southeast include tomatoes, parsley, and basil. Tomatoes deter asparagus beetles, while parsley attracts beneficial insects that prey on asparagus pests. Basil also repels asparagus beetles and thrives in our hot, humid climate.

Avoid planting asparagus near onions and garlic. These alliums can inhibit asparagus growth. Creating a diverse and well-planned garden will help your asparagus thrive in the Southeast.