OHIO VALLEY— Consumers enjoy fresh vegetables and ready-to-plant flowers as a result of months of effort on the part of farmers, but few are exposed to the process it takes to get them to market.
In nature, seeds are subject to ever-changing weather conditions. Greenhouses, or as they are referred to in southeastern Ohio — hothouses — make it possible for farmers to sow seeds at any time of year.
No longer dependent on nature to germinate seeds, hothouses enable farmers with more options of when to plant.
After the seeds have germinated, hothouse temperatures can regulate the speed of growth to some degree. In cases of extreme weather changes during planting season, they can also be kept safely in the hothouse to avoid damage by frost or freezing temperatures.
Work begins in January, as hothouses are readied for planting. Plastic has replaced glass for covering greenhouses, and if using an established structure, the covering is carefully examined for tears and leaks. A special type of plastic is also used on the floors.
Heating, irrigation and ventilation systems are checked and necessary repairs made before the planting begins. Most hothouses in the area are heated with natural gas, allowing for a more consistent and easier-to-maintain heating system than the previous coal-burning stoves. A good circulation system is necessary or plants may suffer from fungal diseases and a reliable source of water is essential to maintaining seed germination and continued plant growth.
Most seeds are hand-sewn in plastic trays with individual cells filled with a mix of vermiculite and peat moss. The most common cause of failure when starting seeds is desiccation, or drying out, and vermiculite’s moisture retaining properties keep the soil materials evenly damp even under hot, sunny conditions, enhancing seed germination.
Temperatures must be regulated so that each type of plant receives the proper climate. Some need to be cooler than others, so like crops must be planted in the same hothouse for best results.
Cabbage is a cold-weather crop, which means it prefers a cooler growing season. Seeds are sewn in February and the temperature is kept around 80 degrees through germination. Once sprouts begin showing, temperatures are dropped to around 65 degrees. Cabbage can usually be put into the ground by the end of March to early April.
Tomatoes, peppers, melons, cucumbers and squash are warm-weather crops, and seeds are sewn around mid-April. Germinating temperatures must be kept between 85 and 90 degrees. After sprouting, the temperature is set around 75 degrees. Warm-weather crops are more sensitive to temperature changes than cold-weather crops, and must be planted later to avoid drops in temperature, usually in late May.
Flower plants require temperatures to be maintained at between 50 to 60 degrees, depending on the type of plant.
About two weeks before the plants are either shipped to market or transplanted into the fields, they must be readied for life outside the ideal conditions of the hothouse in what is known as a hardening process
“Hardening off” gradually introduces the tender plants to the change that will occur when they are placed in their permanent outdoor environment. This process thickens the cuticles on the leaves and as a result, they lose less water and acclimate to fluctuating temperature and water conditions.
Plants that have not been properly hardened can experience transplant shock, causing them to languish. This makes them more susceptible to disease, their growth can become stunted and many times the plants die before reaching maturity.
Finally, the plants are ready to be put into the ground; the hothouses are empty, and another aspect of farming begins. Next month, we will explore the proper planting conditions for a successful harvest.