Bulb Vegetables – Garlic, Onions, Leeks, Shallots

Bulb Vegetables – Garlic, Onion, Leek, Shallot

Bulb vegetables are among the oldest cultivated crops in the world – garlic and onions have been grown for over 5,000 years. In a Czech garden, they are absolutely indispensable: garlic naturally repels pests, onions form the foundation of countless dishes, leek brings a delicate flavor to autumn and winter cooking, and shallot replaces onion everywhere that every detail matters with its sweetness and complexity. All varieties share similar basic requirements – light, well-draining soil, full sun, and restraint in nitrogen fertilizing. This guide will take you from selecting seed sets through daily care to crop storage.

Shared Table – Quick Overview

1. Garlic (Allium sativum)

Garlic is irreplaceable in a Czech garden – it naturally repels aphids and other pests, and its aroma is unmatched in the kitchen. The correct choice of type and adherence to planting time determine both the size and quality of the resulting bulbs.

Hardneck vs. Softneck

For Czech conditions, hardneck is ideal – it reliably survives winter, produces large regular cloves, and scapes are a bonus delicacy not to be missed.

Planting

Autumn Planting (recommended):
The ideal time is October–November, approximately 4–6 weeks before the ground freezes permanently. Garlic needs a period of cold – vernalization – as a signal for forming a full-fledged bulb. If you skip this step, you'll harvest a cluster of separated cloves in summer rather than a compact bulb.

1. Selecting Seed Stock: Procure exclusively seed garlic – supermarket varieties are often treated with sprout-inhibiting preparations, come from different climatic conditions, and may carry unsuitable diseases. Seed stock from verified suppliers guarantees healthy, vital plants.
2. Clove Preparation: Separate the bulb into individual cloves immediately before planting. Use only large, firm outer cloves – small cloves from the center of the bulb are better left for the kitchen.
3. Depth: 5–8 cm, tip up, base down. In colder locations, plant toward the deeper end (8 cm); depth better protects against frost.
4. Spacing: 10–12 cm in row, 25–30 cm between rows.
5. Mulching: Cover the bed with a layer of straw or dry leaves (5–10 cm). Mulch protects cloves from deep frost and suppresses weeds in spring before they emerge.

Spring Planting:
Possible with softneck and more tolerant hardneck varieties, but without vernalization, bulbs tend to be significantly smaller. Plant as early as possible in March, once the soil allows.

Care

• Watering: Regular from April to June, especially in a dry spring. From the turn of June and July, gradually reduce watering – garlic needs drier conditions for ripening and slipping of bulb scales.
• Fertilizing: Garlic dislikes fresh manure and excess nitrogen – the result is soft tissues and poorly storable bulbs. Work in ripe compost in autumn; add phosphorus and potassium in spring for firm, long-lasting bulbs.
• Scapes: On hardneck in May–June, break off the flower stem once it forms its first curl into a spiral. The plant redirects energy from seed formation to the bulb – the difference in weight can be 20–30%. Don't discard scapes – they excel grilled, sautéed in butter, or blended into pesto.
• Weeding: Garlic in early development poorly tolerates weed competition. Mulch significantly reduces manual weeding frequency.

Diseases and Pests

• Garlic Rust: Orange-brown pustules on leaves reduce photosynthetic area and impair ripening. Maintain airy spacing, don't water over foliage. Remove heavily infected leaves and destroy them – don't compost.
• Fusarium Rots: Manifested by softening and browning of the stem base and bulb. Essential prevention is healthy seed stock, strict crop rotation (at least 4–5 years gap), and well-draining substrate that doesn't retain water.
• Onion Fly Maggots: Larvae bore into leaves and stems. Sound physical barriers like row covers placed over the bed after planting are effective prevention.
• Onion Eelworm: Infested bulblets are swollen and deformed. The only reliable protection is healthy certified seed stock and strict crop rotation.

Harvest and Drying

When to Harvest:
- Hardneck: June–July, once the bottom third to half of the leaves dry, with 5–6 green leaves remaining at top.
- Softneck: once the foliage begins to bend and lie down.
- Don't wait for the entire foliage to dry completely – in that case, protective scales crack and the bulb disintegrates in the soil, with significantly reduced storability.

Procedure:
1. Gently undercut bulbs with garden forks – never pull directly on the foliage; it easily separates from the bulb.
2. Leave bulbs 2–3 days to dry right in the bed (in dry weather only), or move them under cover.

Drying (Curing):
1. Hang bundles of garlic or lay them on airy racks in a dry, shaded space with good air circulation.
2. Dry 4–6 weeks – scales must have a paper-like texture and roots must be hard and dry.
3. Trim roots and leave 3–5 cm of foliage, or braid softneck into traditional braids.

Storage: Dry, airy space with temperature 10–15 °C or 0–4 °C. Avoid 5–10 °C range – garlic actively sprouts in this band and quickly deteriorates. Hardneck lasts 6–10 months, softneck 8–12 months.

2. Onion (Allium cepa)

Onion is the most versatile vegetable in beds and kitchen alike. In the garden, it can be grown three ways – from sets, from seed, or from transplants (pre-grown seedlings). Each approach has different requirements and advantages.

Growing Methods

Growing from Sets

Sets are small bulbs about 1–2 cm in diameter; plant them in spring and they develop into full-size harvest onions by summer. It's the most straightforward growing method.

1. When: March–April, once the soil allows working. Sets easily tolerate light frost to -5 °C.
2. How: Plant tip-up so the tip slightly protrudes above soil surface. Depth: 2–3 cm. Too-deep planting slows development and increases rot risk.
3. Spacing: 8–10 cm in row, 25–30 cm between rows.
4. Proven Set Varieties: Stuttgarter Riesen (yellow, reliable and excellent storage), Centurion F1 (yellow, resistance to bolting), Red Baron (red, pronounced flavor).

Growing from Seed

1. Pre-growing: Sowing in February into trays in warmth (15–20 °C). Transplant into bundles of 3–5 plants – planted together they support each other and hold upright better.
2. Outdoor Planting: April after gradual hardening. Spacing 10–12 cm.
3. Direct Sowing: From March in beds, depth 1 cm. After emergence, thin to 10 cm spacing – thinned plants can be added to soups as spring onion.
4. Suitable Varieties: Vštar, Maja, Exhibition (extremely large bulbs for show purposes), Rijnsburger (excellent storage), Red Karmen (red, delicate flavor).

Care

• Watering: Regular and generous in the first half of vegetation (April–June). In July, stop watering completely – onions must ripen, scales harden, and the neck dry. Late watering prolongs vegetation and shortens shelf life.
• Fertilizing: Fresh manure is fundamentally unsuitable. Work in ripe compost in autumn. A mild dose of potassium in June supports ripening and formation of firm protective scales.
• Weeding: Onions with a shallow root system poorly compete with weeds. Regular hand weeding or organic mulch are essential, especially in the first weeks after planting.

Harvest and Storage

When to Harvest: Once approximately half of the foliage bends and lies on the ground. Never artificially bend or step on the foliage – mechanical injury to the neck reduces storability and opens the door to disease.

Procedure:
1. Pull onions and leave 2–3 days to dry right in the bed.
2. Move under shelter and dry 2–3 weeks until scales crackle like paper and the neck is completely dry.
3. Trim roots and foliage, or braid softneck-style.

Storage: Dry, airy place with temperature 0–5 °C. Yellow onion lasts 4–8 months, red 3–5 months (less tannin in scales = shorter life). Best varieties for long-term storage: Stuttgarter Riesen, Centurion F1, Rijnsburger.

3. Leek (Allium ampeloprasum var. porrum)

Leek is the most elegant member of the onion family – delicate, mildly sweet flavor, silky texture after cooking, and the ability to overwinter directly in the bed place it among the most valued winter vegetables. Growing requires patience due to the long vegetation period, but the reward is fresh greens when beds otherwise stand empty.

Varieties

• Summer and Autumn: Megaton, King Richard, Carlton F1. Faster development, excellent yields, but lower frost tolerance – harvest before first hard frosts.
• Winter: Bluegreen Winter, Bandit, Carentan. Tolerate frost to -15 °C and well below zero; harvest from October continuously through March.
• Historic Giant Variety: Musselburgh. Vigorous, distinctly aromatic stems with excellent flavor, time-tested over generations.

Pre-growing and Planting

Leek is almost always pre-grown – direct sowing in the bed is tedious and unreliable.

1. Sowing: February–March into trays or seeders. Depth 1 cm, temperature 15–18 °C. Seedlings initially resemble thin grass – that's normal.
2. Germination: 10–14 days. If cooler, germination extends.
3. Outdoor Planting: May–June, once seedlings reach approximately 6–8 mm thickness (pencil-thin). Earlier planting of weak plants isn't advantageous.
4. Hole-Planting Technique: Make holes in the bed with a wooden tool (dibber) approximately 12–15 cm deep and insert individual seedlings. Don't cover with soil – water thoroughly. Water gradually fills the hole and the stem naturally blanches without extra work.
5. Spacing: 10–15 cm in row, 30–40 cm between rows.

Care

• Watering: Regular throughout vegetation. Leek is one of the most water-demanding vegetables – drought causes stiff stems and bitter flavor.
• Fertilizing: Moderate nutrient requirements. Side-dress twice per season with balanced fertilizer or compost tea – before hilling and in August.
• Hilling: Progressive earthing up around stems through summer extends the white, tender, edible portion. As alternative, wrap paper or newspaper cylinders around stems.
• Mulching: Organic mulch (straw, grass clippings) suppresses weeds and maintains even soil moisture.

Diseases and Pests

• Leek Leafminer (Napomyza gymnostoma): Most serious leek pest in Czech conditions. Larvae bore spiral tunnels in stems, ruining them. Row covers placed over the bed from planting through late June are most effective prevention. Maintain strict crop rotation.
• Leek Rust: Characteristic orange spots and pustules on leaves weaken through autumn. Maintain airy spacing, don't water over foliage, and remove heavily affected leaves.

Harvest

• Summer and autumn varieties: from September, once the stem reaches 3–4 cm thickness at the base.
• Winter varieties: overwinter in the bed and harvest continuously as needed from October through March. After hard frosts pass, stems soften again and are fully usable.
• Always use garden forks when harvesting – roots grip the soil firmly and hand-pulling risks damage.

4. Shallot (Allium cepa var. aggregatum)

Shallot is a delicate relative of onion, highly valued in professional gastronomy for its complex, sweetly subtle flavor without aggressive pungency. In the garden, it's undemanding, naturally multiplies vegetatively, and under good conditions stores longer than regular onion.

Varieties

• Yellow: Longor, Jermor, Ambition F1. Most widespread group, excellent ratio of yield to storability.
• Red and Purple: Red Sun, Zebrune. Decorative appearance on the plate, distinctly more delicate flavor.
• Banana Shallot (echalion): Elongated shape resembling a banana, exceptional sweetness. It's a shallot-onion hybrid, favored in French cuisine.

Planting

Shallot is grown almost exclusively from sets (vegetatively from divided bulbs), not from seed.

1. When: March–April for summer harvest or October–November for early harvest next year.
2. How: Plant bulbs tip-up so the tip barely protrudes above soil surface. Depth: 2–3 cm.
3. Spacing: 15–20 cm in row, 25–30 cm between rows. Shallot expands into clusters during vegetation – dense planting limits them.
4. One planted bulb produces a cluster of 5–12 new bulbs – that's the essence of its growing and why you always set aside part of the harvest as seed for next year.

Care

• Watering: Mild and regular. Shallot dislikes constant wetness – roots rot, fewer bulblets form, and they're waterier.
• Fertilizing: Minimal. Ripe compost worked in autumn typically suffices for the entire season.
• Weeding: Regular – shallot in a dense cluster poorly competes with weeds, especially in the first half of summer.

Harvest and Storage

• Harvest: July–August, once foliage naturally lies down and yellows.
• Drying: 1–2 weeks in a dry, airy, shaded space. Don't separate bulblets from one cluster immediately – let them dry naturally together.
• Storage: Dry, cool place with good air circulation. Shallot is among the longest-storing bulb vegetables – under proper conditions lasts 6–12 months. Always set aside part of the finest harvest as seed for next season.

5. Common Principles for Bulb Vegetables

Soil

Bulb vegetables without exception require light, well-draining, humus-rich soil with pH 6.0–7.0. Heavy, clayey, or waterlogged soil is a direct ticket to rots and root diseases. Improve clay soils annually by adding coarse sand and ripe compost – results appear after 2–3 seasons.

Fertilizing – Essential Rule

Never fertilize bulb vegetables with fresh manure – it causes soft tissues, excessive vegetative growth, rots, and spoiled harvest. Work in ripe compost at least 2 months before planting, ideally during autumn bed preparation.

Crop Rotation

Plant bulb vegetables on the same spot no sooner than 4–5 years. Soil accumulates onion fly larvae, fusarium fungi, and other pathogens specialized on genus Allium. Breaking this rule manifests quickly, and correcting the resulting imbalance is difficult.

Good Previous Crops: Legumes (peas, beans), cucurbits, tomatoes.
Poor Previous Crops: Any other bulb vegetables, tulips, or daffodils – they share the same spectrum of pests and pathogens with genus Allium.

6. Gardening Calendar for Bulb Vegetables in Czech Republic

7. Frequently Asked Questions (FAQ)

What's the difference between hardneck and softneck?
Hardneck forms a rigid central stem – the scape – ending in an inflorescence. It has fewer cloves, but they're larger and regular; flavor is more pronounced. Softneck lacks scapes, has more smaller cloves, more delicate flavor, and longer storage. For Czech conditions, hardneck is better – survives winter well and produces robust bulbs.

Can I plant grocery store garlic?
Technically yes, but results are usually disappointing. Market garlic is often treated with sprout-inhibiting preparations, comes from climatically different regions, and may carry unsuitable diseases. Procure seed garlic or bulb vegetable seeds from verified Czech suppliers.

Why doesn't my garlic form large bulbs?
Most common causes: spring planting without vernalization, overly dense planting, insufficient direct sun, weedy beds, or excess nitrogen in soil.