- What is a shade house?
In hot summers or during extreme heat waves, the internal temperature of a greenhouse can quickly rise to a point where the plants quickly suffer and even die. Even aggressive ventilation may be inadequate to keep temperatures at safe levels. In these circumstances, growers create shade houses to protect their inventory from the effects of excessive heat and sun. The structures can be built of poles and covered with black, green, or white polypropylene fabric depending on the degree of shade needed. Black is the most effective at temperature reduction since it retains heat outside the greenhouse.
Shade fabric can also be installed on mechanisms within a greenhouse and deployed at the push of a button or on a schedule during the height of summer.
- What loads does a greenhouse structure have to carry?
When you’re designing your greenhouse’s structural components, you’ll need to allow for more than just the weight of the roof itself. Keep these additional factors in mind:
- Dead load - the weight of all permanent materials like frame materials, cover, pipes, ventilation equipment and irrigation setup.
- Live load - the combined weight of hanging baskets, shelves, plus anyone working on the roof.
- Wind load - the force of wind on the structures during severe weather, both sustained winds and gusts
- Snow and ice load - the weight of potential accumulations of snow and ice on the roof - the loads will be determined by the local climate and weather patterns. There may be specific remedies to deal with potential snow accumulation where it tends to be a problem.
- What are the advantages of using containers in a greenhouse?
Containers may seem like an unnecessary expense if you’re accustomed to working in a nursery environment, but they offer some important advantages:
- Increased production capacity
- Plant growth is uniform with good vigor
- Very little transplanting shock
- Stock is easy to handle and shift
- Sanitation steps are simplified
- Drainage and aeration are simplified
- Plant health can be easily monitored, and problems quickly addressed
- Containerized plants offer an Ideal configuration for modern irrigation techniques.
- Produce is largely protected from damage resulting from ground contact
- What are the most important properties of growth media for greenhouse farming?
Greenhouse farming requires growth media with very different properties than nursery or open-field farming. Keep these points in mind:
- Growth media should have good holding capacity and porosity
- Growth media should be well drained - avoid any standing water
- Growth media should have good aeration to facilitate healthy root growth
- pH level of the growth medium should be on the acidic side, typically in the 5-7 range.
- Low pH can be corrected by adding lime; High pH can be corrected by adding sulfur or gypsum.
- How can I use thermal mass in a traditional greenhouse?
Thermal mass refers to the ability of a mass to store heat and this property can be easily employed as a passive source of nighttime heat (or daytime cooling) to augment existing systems. The amount of heat any mass can store is called volumetric heat capacity (VHC). Water has the highest VHC of any common material, is easy to obtain, transport and store, so it’s by far the most popular material used for thermal mass.
Many greenhouse operators fill large barrels of water with water. Painting the exterior of the barrels black improves efficiency by increasing their ability to absorb heat. The barrels are placed in a location where they can receive plenty of sunlight and where the heat they emit at night can be easily circulated around the greenhouse. Keep in mind that barrels are not the only option for storing water for this purpose - any durable container in any size or shape can be used - look for locations where containers are exposed to sunlight and yet won’t shade out your plants.
