Growing tomatoes at home is ideal for the avid chef or gardener. Even better? Being able to grow tomatoes in a greenhouse so you can enjoy the rich fruit year-round without being concerned about the weather or climate at any time. The dozens of varieties of tomatoes contain lycopene, a powerful antioxidant, as well as vitamins C and A. When growing tomatoes in a greenhouse, it is important to ensure proper soil preparation and that the tomatoes get enough sunlight inside the greenhouse.
Prepare the tomato seed soil. Combine about 10 percent worm castings with the potting soil mix. Adjust the pH slightly by adding 1 tsp. of lime per gallon of soil. This ensures that blossom end rot doesn't hit the tomato plant when it is mature. Spritz the soil lightly with water to moisten it before planting. Fill the seedling trays with prepared soil.
Insert each tomato seed 1/4 inch deep into the soil with your finger. Plant around 8 seeds per inch of soil. Moisten the soil with the water bottle again. Cover with a moistened cheesecloth for two days after planting. This ensures the seeds don't dry out. Keep the temperature in the greenhouse around 80 degrees Fahrenheit for the seeds to germinate for about two weeks.
Discard the cheesecloth once the tomato seeds germinate. Provide the seedlings 12 hours of sunlight per day with natural sun or grow lights.
Fill the 6-inch planter with the prepared soil mix. Create shallow holes in the soil with your fingers. Transplant the seedlings to these holes once they are 2 inches tall. Do this by carefully tugging up the seedlings and roots with your fingers. Set them in the hole you made in the 6-inch planter.
Keep an ideal temperature for maturation of about 74 degrees Fahrenheit during the day to 64 degrees at night.
Water the tomato plants after transplanting to make the soil moist. From here on out, keep the soil consistently moist but not soaked. On average this means you should water about once every couple days.
Keep 12 hours of sunlight on the tomatoes until they are four inches tall. At this time, fertilize the plants with a 16-16-16 fertilizer.
Transplant the tomato plants when they are about one foot tall to the 1-gallon planter. Do this by using a trowel to scoop up the plants underneath and bring them to the pot with prepared soil.
Keep an eye on the plants until they start to flower within eight weeks. This means fruiting will begin about two months later. Harvest tomatoes when they look and feel heavy on the branch and the flesh is firm, with a pinkish red hue.