How to Grow Grapes in Iowa

Iowa’s cold winters and hot summers can be challenging for some crops, but grapes, particularly cold-hardy varieties, thrive in these conditions. With proper care and the right grape varieties, you can cultivate a successful vineyard or backyard grapevine in Iowa.

1. Choosing the Right Grape Varieties

Cold-hardy grape varieties are best suited for Iowa’s climate:

  • Frontenac: A versatile grape that produces red wine and performs well in cold climates.
  • Edelweiss: A white grape that is popular for both fresh eating and winemaking.
  • La Crescent: A cold-hardy variety that produces aromatic white wines.
  • Concord: Known for its hardiness, Concord is a popular choice for juice and jelly.

2. When to Plant

The ideal time to plant grapevines in Iowa is in early spring, after the danger of frost has passed, usually in April.

  • Dormant vines: Planting dormant bare-root grapevines is recommended in early spring for the best establishment.

3. Soil Preparation

Grapevines thrive in well-drained soil with a slightly acidic pH.

  • Soil type: Sandy loam is ideal for grapevines, but if your soil is heavy clay, add organic matter to improve drainage.
  • Soil pH: Grapevines prefer a pH of 5.5 to 7.0. If needed, amend the soil to ensure optimal pH levels.
  • Fertilization: Add compost or a slow-release fertilizer before planting to provide nutrients for the growing vines.

4. Planting and Spacing

  • Planting depth: Plant vines about 8-10 inches deep, spreading the roots out gently in the hole.
  • Spacing: Space grapevines 6-8 feet apart in rows, with 8-10 feet between rows to allow proper airflow and vine growth.

5. Training and Pruning

Training and pruning grapevines are essential for healthy growth and high yields.

  • Training system: Use a trellis system to support your vines. The vertical shoot positioning (VSP) system is common in Iowa, as it helps vines grow upward, promoting good air circulation.
  • Pruning: Prune grapevines during the dormant season (late winter or early spring). Remove about 90% of the previous year’s growth, leaving only the strongest canes to bear fruit.

6. Watering

Grapes require consistent watering, especially during their first few years of growth.

  • Watering frequency: Water deeply once a week, providing 1-2 inches of water. Avoid overwatering, as grapes do not tolerate soggy soils.

7. Pest and Disease Management

Iowa’s humid summer conditions can encourage fungal diseases, so proactive management is key.

  • Black rot and downy mildew: Common fungal diseases in Iowa vineyards. Use fungicides and space vines properly to increase airflow and reduce disease risk.
  • Japanese beetles: These pests can cause damage to leaves. Hand-pick them or use traps to control infestations.

8. Harvesting

Grapes in Iowa are typically ready for harvest in late summer or early fall.

  • Harvest time: Grapes are ripe when they have fully colored and reached the desired level of sweetness. Taste a few grapes to determine their readiness.
  • Harvest method: Use pruning shears to snip grape clusters from the vine, being careful not to damage the fruit.

Conclusion

Growing grapes in Iowa can be highly rewarding with the right care and selection of cold-hardy varieties. By preparing your soil properly, training your vines, and managing pests and diseases, you can enjoy a productive grape harvest year after year.