Poison Ivy in The Garden + Ginger? Turmeric? Jicama? Horseradish?

Episode Overview

• This episode of Growers Daily addresses common challenges faced by small-scale organic market gardeners, focusing on weed management, crop selection, and summer environmental controls.
• Host Jesse Frost answers patron questions about safely and effectively managing poison ivy infestations without using synthetic herbicides.
• The episode analyzes the financial viability and space requirements of high-value specialty root crops like ginger, turmeric, horseradish, and jicama.
• It explores the practical application of shade cloths in high tunnels, discussing how shade percentages affect crop growth and how ventilation can sometimes replace the need for shading.

Key Concepts

• Poison Ivy as a Low-Competition Weed: While poison ivy is highly dangerous to touch, it behaves as a non-aggressive weed in cultivated garden beds. Unlike in forest ecosystems where it climbs and dominates, a simple physical intervention (like hoeing or manual extraction) can permanently eradicate it from a bed without the need for chemical herbicides.
• The Opportunity Cost of Long-Season Root Crops: Crops like ginger and turmeric are tropical, slow-growing plants that occupy valuable bed space for five to nine months. For northern growers, this requires heated greenhouse space during transitional months, meaning these crops must command a high price premium to justify the loss of multiple successions of fast-turnover crops like salad greens.
• The Synergy of Plastic Diffusion and Shade Cloths: Greenhouse plastic naturally diffuses sunlight and provides a baseline of 5% to 10% shade. When calculating shade cloth requirements for summer crops, growers must factor in this existing light reduction to avoid over-shading, which can stunt crop development.
• Airflow Over Shading: High temperatures in tunnels are often caused by stagnant air rather than excessive solar radiation. Increasing ventilation through high hip boards, roll-up sides, or ridge vents is often more effective at cooling plants than installing heavy shade cloths.

Quotes

• At 3:31 - "Poison ivy is generally not the most competitive weed in the world." - Explaining that while poison ivy is noxious to humans, it does not aggressively outcompete vegetable crops in a well-managed garden bed.
• At 8:08 - "What you will often see with those two crops in particular is people either growing a ton of it or almost none of it at all." - Pointing out the stark divide among growers regarding ginger and turmeric due to their high startup costs and long season requirements.
• At 15:05 - "To me though, ventilation is going to get you really far in high tunnels." - Highlighting that proper airflow is often a more critical factor for summer crop health in tunnels than blockading the sun with shade cloth.

Takeaways

• Eradicate poison ivy manually with extreme caution: Use thick gloves to carefully pull the roots or chop them out with a hoe. Never burn poison ivy, as the toxic oils (urushiol) become airborne in the smoke and can cause severe lung damage, and avoid composting it to prevent spreading the oils into your soil mix.
• Test specialty root crop demand with a "baby" harvest: Instead of trying to grow fully cured ginger or turmeric over a nine-month period, harvest them early as "baby ginger." This requires less time in the ground, eliminates the need for curing, and is highly popular among restaurant chefs and farmers' market customers.
• Opt for a 30% shade cloth for general summer cooling: If you choose to shade your high tunnel, a 30% black or aluminet shade cloth offers the best balance of heat reduction without excessively starving sun-loving crops like tomatoes and peppers of the light they need to fruit.