Preventing Lettuce From Bolting and Going to Seed Early

Understanding Lettuce Bolting and How to Prevent It

Lettuce is a cool weather crop that is popularly grown in home gardens and commercially due to its versatility, ease of growth, and health benefits. However, there can be some challenges with growing lettuce, specifically the issue of bolting, which refers to lettuce "bellying up" and sending up a flowering stalk before forming a full head.

What Causes Lettuce Bolting

Lettuce is triggered to bolt and flower early for a few key reasons:

• High temperatures - Once temperatures reach above 75F, lettuce will start sending up a seed stalk
• Age of plant - Older lettuce plants that have matured for over 2 months are more prone to bolting
• Lack of nutrients - Insufficient nitrogen in particular can cause early bolting
• Excess sunlight - Too much sun exposure can stress the plant and initiate bolting
• Crowding - Lettuce that lacks proper spacing and becomes rootbound may bolt more quickly
• Drought stress - Lack of consistent moisture makes the plant try to complete its lifecycle faster
• Variety - Some lettuce varieties, like looseleaf, bolt quicker while romaine is more bolt resistant

Identifying Lettuce Bolting

It's important to catch lettuce bolting early before the quality and flavor detiorate too much. Here's what to look for:

• Elongated center and loose interior leaves
• Bitter or off taste
• Early seed stalk emergence
• Wilting even with adequate moisture

Once you see these signs, it likely means the lettuce should be harvested even if heads or leaves are undersized. The rising stalks will become woody and bitter once flowering happens.

Tips to Prevent Lettuce From Bolting

While we can't always control hot weather, there are some lettuce growing methods that can help reduce bolting:

Choose Bolt Resistant Lettuce Varieties

The first line of defense is selecting lettuce types that are less prone to bolting:

• Romaine - The most heat tolerant and slow to bolt option that forms tight upright heads
• Summer Crisp - Heat tolerant butterhead types with good bolt resistance
• Jericho - Looseleaf variety that withstands heat and resists bolting longer
• Arctic King - Butterhead known for being a slow bolting option
• Speckles - Beautiful red romaine type with good bolt tolerance

Let Lettuce Mature Before Hot Weather

Timing your planting so that lettuce matures before peak summer heat is crucial. This means sowing seeds of quicker growing varieties like looseleaf and oakleaf types 3-4 weeks before your last average spring frost date.

For heat loving romaine and crisphead types, sow them 4-6 weeks before your region's last frost so they size up before temperatures rise.

Provide Afternoon Shade

Shielding lettuce beds with shade cloth, shade structures, or planting on the east side of larger plants are organic ways to prevent excessive sunlight and heat exposure that leads to bolting. Provide at least 30% shade in mid-day.

Use Row Covers

Floating spunbond row cover over lettuce blocks wind, protects from insect damage, and keeps soil cooler. Drape the fabric directly onto beds and secure the edges with stones, boards, or ground stakes. Ventilate on very hot days.

Improve Soil Fertility and Moisture

Enrich soil with 2-3 inches of compost or well rotted manure before planting. Side dress growing lettuce with a balanced fertilizer or compost tea every 2-3 weeks. Consistent soil moisture will also help prevent drought stress and early bolting.

Give Adequate Spacing

Thin lettuce seeds and transplant starts to proper spacing for each variety. Crowding causes competition for resources like nutrients, light, and water - leading to bolting. Space romaine types 8-10 inches apart in rows 12 inches apart.

Coping With Bolted Lettuce Plants

Even with the best care, lettuce may still occasionally bolt if weather is unusually hot. Here's how to make use of bolting lettuce:

Harvest Early and Often

Picking outer lettuce leaves for use in salads and sandwiches helps slow further bolting. Timely, frequent harvests ensure you get usable leaves before bitterness sets in.

Grow for Lettuce Seeds

If flowers do emerge, allow some lettuce plants to continue growing to produce abundant seeds for future planting. Dry and collect seeds once they turn brown and papery.

Substitute More Heat Hardy Greens

Once lettuce bolts or the summer heat arrives, replant beds with heat loving greens like Swiss chard, collards, kale, arugula, beet greens, orach, and Asian greens which will thrive until fall.

By selecting bolt resistant lettuce varieties, using protective measures against heat and sunlight, providing optimal growing conditions, and promptly harvesting, you can significantly reduce lettuce bolting and belly up problems. With some adaptation, lettuce can be sucessfully grown in all but the very hottest climates.

Disclaimer: This article is for informational purposes only and does not constitute medical advice. Always consult with a healthcare professional before starting any new treatment regimen.