Growing vegetables, flowers and herbs in a greenhouse gives a gardener a year-round gardening season by limiting the effects of Mother Nature. Growing in a greenhouse means controlling the temperature, humidity, light conditions and water to ensure rapid and healthy plant growth. Using a greenhouse to grow crops is productive and cost-efficient for some crops, although the initial capital investment can be substantial. Once your greenhouse is set up, it is time to get ready to grow your plants.
Make sure your growing trays are clean and disinfected. Clean out any soil residue, wash with soapy water and dry completely.
Organize areas of your greenhouse for starting seeds, growing seedlings and growing mature, fruiting plants since growth stages benefit from different light conditions. You also need to have separate areas for cool-weather and warm-weather crops or grow them at different times. Be sure to leave space to move among the growing areas to prune and harvest your produce.
Set up grow lights that supplement natural light for a total of 12 to 14 hours of light per day. In general, fluorescent lights work but are less effective overall than special-purpose grow lights such as metal halide (MH) and high-pressure sodium (HPS) lights. Of the special-purpose lights, MH lights have a blue light that resembles spring for seeds and young plants. HPS lights have orange and red light that is similar to the natural light of fall or late summer and encourages fruiting. Suspend lights 1 foot to 6 feet above the plants, depending on their wattage.
Check your equipment to make sure it is in operational condition, including sprayers for watering, timers for lights, temperature controls for heat and cooling, fans to move air and vents to allow in fresh air to reduce humidity.
Purchase seeds or transplants.
Place seeds in starter containers with good potting soil to a depth of three times the seeds' length and dampen. Keep seeds damp until they sprout, but do not let them become soggy. Place transplants into growing trays or containers that have sufficient depth for the roots of mature plants. Fill containers or growing trays with potting soil and water. Fertilize plants according to package directions.
Set timers for light, sprayers for watering and controllers for temperature.
Control pests. Insects and diseases can attack greenhouse growing plants, so check your plants frequently for signs of distress. Read the instructions on pest- and disease-control products to make sure that they are approved for use in a greenhouse growing environment and use according to directions.