Trailside Organic Farm Greenhouse Update, March 2024

Submitted by Ian Frederick, Trailside Organic Farm Manager

You may recall hearing that Katie and I ran an indoor grow room last season to raise transplants for the Trailside Organic Farm. In fact, we grew all our farm transplants in this setting during 2023. Although this method of seed starting is novel, feasible and worth trying in a pinch, there are certainly some drawbacks to growing plants
this way. Topping this list would be the lack of natural sunlight in a grow room. In contrast, a traditional greenhouse provides plants with an environment of natural light and day length cycles which encourage plants to grow properly and thrive. The grow room also left us minimally equipped to control air circulation, heat and moisture levels. A greenhouse, on the other hand, provides an open, airy space with fans, vents, and a thermostat-controlled heater to give us some more authority over these important factors. Improper moisture, air circulation and temperature levels can cause pest and disease pressure if managed improperly, further encouraging us to build a greenhouse at the Trailside Organic Farm.

Relying on the grow room also introduced a lag time in our operation. Growing transplants indoors appeared to set our spring production back by one week or more. A light source which is exclusively artificial presents the need to acclimate plants to natural sunlight before planting outdoors. If we skipped this week-long step last season, we observed that plants would show signs of shock and slow significantly in terms of growth and root setting once placed in farm soil.

Although LED lights are often used as supplemental lighting in greenhouses, the need to acclimate plants to natural lighting is rarely necessary if raised in a greenhouse. Please note that acclimating plants to cooler outside temperatures, often referred to as hardening off, is still an important step to consider if growing cold crops in a
greenhouse and planting them outside during the spring.

To reap the benefits that a greenhouse provides, we are currently constructing a basic, temporary greenhouse at the Trailside Organic Farm. Some details on the temporary structure are provided below, and we estimate a completion date by early March.

Features and Specifications of Temporary Greenhouse

• Frame – Tubular high tunnel frame with three purlins
• Shape – Standard arch
• Dimensions – 30’ x 50’ (base), 11’ (peak height); 4’ (sidewall height)
• Floor – Woven weed fabric
• Foundation – None: Ground posts driven into soil
• Covering – 6-mil greenhouse plastic, double covered with inflation blower
• End Wall Construction – Wood frame covered with polycarbonate and plastic film
• Heating – 34,000 BTU electric heater
• Ventilation – Three vents on each end wall
• Number of tables- Ten 4’x8’ greenhouse benches
• Supplemental Lighting – Ten LED grow lights, re-used from the grow room
• Additional Features – Germination table with heat mat