Onions & Garlic Growing Guide

Introduction to Onions & Garlic

Onions and garlic are essential culinary crops that form the flavor foundation of countless dishes worldwide. Both belong to the Allium family and are prized for their distinctive flavors, health benefits, and long storage capabilities. Onions are biennial plants typically grown as annuals, while garlic is a perennial usually grown as an annual. These cool-season crops are relatively easy to grow and can be cultivated in most home gardens with proper care.

Popular Onion Varieties

Onions come in various types, each suited to different climates and culinary uses:

• Yellow Onions - The most common type, with golden papery skin and white flesh. Excellent for cooking and storage. Varieties include 'Yellow Globe' and 'Patterson'.
• Red Onions - Mild flavor with deep purple skin and red-tinged flesh. Great raw in salads and sandwiches. 'Red Burgundy' and 'Redwing' are popular choices.
• White Onions - Mild, slightly sweet flavor with white skin and flesh. Perfect for Mexican cuisine and fresh salsas. 'White Sweet Spanish' is a common variety.
• Green Onions (Scallions) - Harvested before bulbs form, with long green tops and small white bases. 'Evergreen Hardy White' is a reliable variety.
• Shallots - Mild, delicate flavor with a garlic-onion blend. Form clusters of bulbs. 'Conservor' and 'Picador' are excellent varieties.

Popular Garlic Varieties

Garlic is categorized into two main types with many varieties within each:

• Hardneck Garlic - Produces a central flower stalk (scape) and fewer, larger cloves. Better suited for cold climates. Varieties include 'Rocambole', 'Porcelain', and 'Purple Stripe'.
• Softneck Garlic - No central stalk, more cloves per bulb, and better storage qualities. Ideal for warmer climates. Varieties include 'Artichoke' and 'Silverskin'.
• Elephant Garlic - Not true garlic but a leek relative. Produces very large cloves with mild flavor.

Planting Onions

Onions can be grown from seeds, sets (small onion bulbs), or transplants. Each method has its advantages:

Planting Onion Sets

The easiest method for beginners:

• Plant sets in early spring as soon as soil is workable.
• Choose firm, healthy sets about the size of a marble.
• Plant sets 1-2 inches deep and 4-6 inches apart in rows 12-18 inches apart.
• Position sets with the pointy end up and the root end down.
• Water thoroughly after planting.

Starting from Seeds

For the widest variety selection:

• Start seeds indoors 8-10 weeks before last frost date.
• Sow seeds 1/4 inch deep in seed starting mix.
• Keep soil consistently moist and provide plenty of light.
• Transplant seedlings outdoors 2-3 weeks before last frost.
• Space transplants 4-6 inches apart in rows 12-18 inches apart.

Planting Garlic

Garlic is planted in fall for harvest the following summer:

Planting Garlic Cloves

• Plant garlic 4-6 weeks before ground freezes in fall.
• Separate bulbs into individual cloves just before planting.
• Plant cloves 2-3 inches deep and 4-6 inches apart in rows 12-18 inches apart.
• Position cloves with the pointy end up and the root end down.
• Cover with 3-4 inches of mulch after planting.
• Cloves will establish roots before winter and resume growth in spring.

Soil Requirements

Both onions and garlic thrive in well-draining, fertile soil:

• Ideal pH range is 6.0 to 7.0 for optimal growth.
• Work 2-3 inches of compost into the soil before planting.
• Ensure good drainage to prevent bulb rot.
• For heavy clay soils, amend with sand or organic matter to improve drainage.
• Consider raised beds if your soil is poorly drained.

Watering and Feeding

Proper watering and fertilization are crucial for bulb development:

• Water regularly, providing about 1 inch per week.
• Keep soil consistently moist but not waterlogged.
• Reduce watering as bulbs approach maturity to prevent rot.
• Fertilize with nitrogen-rich fertilizer early in the growing season.
• Switch to phosphorus and potassium fertilizer as bulbs begin to form.
• Avoid excessive nitrogen, which can promote leafy growth at the expense of bulbs.

Common Pests and Problems

Onions and garlic face several common challenges:

• Onion Maggots - Small white larvae that attack bulbs. Prevent by rotating crops and using row covers.
• Thrips - Tiny insects that cause silver streaking on leaves. Control with insecticidal soap or neem oil.
• Downy Mildew - Fungal disease causing yellow spots on leaves. Improve air circulation and avoid overhead watering.
• White Rot - Fungal disease causing white mold on bulbs. Prevent with crop rotation and clean planting material.
• Bolting - Premature flowering caused by temperature stress. Choose varieties suited to your climate.

Companion Planting

Onions and garlic make excellent companion plants:

• Carrots - Onions and garlic repel carrot fly.
• Beets - Alliums improve beet growth and flavor.
• Lettuce - Onions deter aphids that attack lettuce.
• Cabbage Family - Garlic repels cabbage moths and aphids.
• Strawberries - Onions can deter slugs that damage strawberries.
• Avoid planting near beans and peas, as alliums can inhibit their growth.

Harvesting Onions

Harvest at the right time for best storage:

• Harvest green onions when tops are 6-8 inches tall.
• For bulb onions, wait until tops fall over and turn yellow.
• Loosen soil around bulbs with a garden fork before pulling.
• Leave bulbs on the ground to cure for 1-2 days if weather is dry.
• Move to a warm, well-ventilated area for 2-3 weeks to complete curing.
• Once cured, trim tops to 1 inch and store in a cool, dry place.

Harvesting Garlic

Proper harvesting ensures good storage quality:

• Harvest garlic when lower 3-4 leaves turn brown but upper leaves are still green.
• Loosen soil with a garden fork and lift bulbs carefully.
• Brush off excess soil but do not wash bulbs.
• Cure garlic in a warm, dry, well-ventilated area for 2-4 weeks.
• Once cured, trim roots and tops (leave 1 inch of stem).
• Store in a cool, dark place with good air circulation.

Storing and Preserving

Proper storage extends the life of your harvest:

• Onions - Store in mesh bags in a cool, dry place (32-40°F, 60-70% humidity). Sweet onions have shorter storage life.
• Garlic - Store bulbs in mesh bags in a cool, dark place (60-65°F, 50-60% humidity). Avoid refrigeration.
• Dehydrating - Slice and dry onions and garlic for long-term storage.
• Freezing - Chop and freeze onions and garlic for cooking use.
• Pickling - Pickled onions and garlic make delicious condiments.

Container Growing

Onions and garlic can be grown in containers with proper care:

• Choose containers at least 10-12 inches deep with drainage holes.
• Use a well-draining potting mix rich in organic matter.
• Plant sets or cloves at the same depth as in garden beds.
• Water regularly but ensure containers drain well.
• Fertilize every 2-3 weeks with a balanced liquid fertilizer.
• Place containers in full sun for best growth.