Many gardeners enjoy growing fresh vegetables for a few months during the summer. The amount of produce and the growing season usually depend on the climate and the location of the garden. The end of summer also signals the end of the annual growing season. A greenhouse allows you to extend your growing season and provides the opportunity for year-round, fresh vegetables. Like outdoor gardens, greenhouse vegetables require regular care and attention to generate quality produce.
Test the temperature in each area of your greenhouse. Depending on construction, your greenhouse may have cool spots and warm spots. Place thermometers along the walls and the center areas. Check for differences in daytime and nighttime temperatures. Fluctuating temperatures may indicate leaks or faulty heating systems. Although most varieties of vegetables tolerate some temperature differences, large fluctuations can hinder their growth and production. Seal off any gaps or cracks in the walls and ceiling of your greenhouse that cause the temperature to rise and fall within the building.
Plant your small seeds in individual peat pots. Fill your pots with a sterile planting medium and set the seeds at the depth recommended on the seed package. Gently tap the soil to press out air pockets and create even contact between the seeds and the soil. Set the planted pots in your plant trays. Space your plant trays evenly across the worktables in your greenhouse.
Pour water into your trays and allow the pots and soil to soak up water until the surface of the soil becomes slightly damp. The amount of water you require depends on the amount and sizes of your peat pots. Keep the soil slightly damp at all times by using this bottom-watering method. Reduce your water as your plants begin to grow, keeping only the soil near the depth of the roots damp.
Transplant your small seedlings into larger pots after they reach 2 to 3 inches in height. Plant the biodegradable pots into 1 or 2 gallon containers, depending on your type of plant and its expected size at maturity. Set the pots in the drainage trays on your worktables. Allow at least 4 to 5 inches of space between the foliage on each plant to encourage adequate airflow.
Trim, prune and train your greenhouse vegetables, depending on the variety you grow. Snip off any crowded, overgrown sections, as well as broken and damaged stems and leaves. Provide support stakes or cages for your tall, heavy tomato plants and vine vegetables, such as cucumbers and zucchinis. Use overhead wires to anchor very tall varieties.
Fertilize your vegetables about once a month, using a fertilizer labeled for use on your variety of vegetable plants. Use a time-release fertilizer to provide continuous nutrients to the soil surrounding the roots.