Tomato plants are an ideal addition to any garden or landscape, especially since three to four plants can provide a generous harvest within three months of maturity. Tomatoes can be grown outdoors in or in a greenhouse, with the latter being the easiest option because you can control the environment and temperature. There are some key tips to keep in mind when growing the plant in a greenhouse.
Choose a tomato plant variety that is well-known for its easy growing and large bounty. These include types such as Gardeners Delight, Moneymaker and Shirley. Keep in mind that Cordon varieties have to be trained on a stake while bush or trailing varieties need no support. The type you choose will also have variations in the amount of time the fruit will mature and be ready for harvest, so keep this in mind.
Purchase tomato plants that are already growing in planter containers. The tomato plants should be a couple inches tall. Make sure the containers have draining holes in the bottom of them.
Make sure the tomato plants are under greenhouse fluorescent lights for 18 to 22 hours each day. The best temperatures to grow tomatoes in a greenhouse are about 70 to 75 degrees F during the day, and 65 to 67 degrees F in the evening.
Transplant the tomato plants from the containers you purchased the seedlings in once they have grown about twelve inches. The new containers should be about twice the size of a tomato plant's root ball. Be very gentle when transplanting so the process does not shock the plants.
Feed the tomato plants with a nutrient-rich, nitrogen fertilizer, such as Maxsea 16-16-16, after transplanting.
Keep the tomato plants well-watered. A drip irrigation system is ideal. The key is to keep the soil moist, but not soaking wet. Not enough water produces bitter fruit, but too much water will contribute to root rot.
Support the tomato plants with with wooden stakes as soon as they grow larger then twelve inches, if your tomato plant is a climbing variety such as Cordon. Loosely tie twine around the main stem of the tomato plant to the wooden stake. Pinch out all side shoots when the tomato plant is under fifteen inches tall.
Pollinate the flowers on the tomato plant once it starts to bloom, around six to eight weeks after planted in the greenhouse. Gently smooth a soft-bristle brush over the flowers on each plant every day the plant is in bloom. Pollinate the flowers at the warmest and most humid part of the day so the greenhouse will be at its warmest.
Harvest your tomatoes when the fruit has ripened to its final color, usually yellow or red. Look for color consistency throughout the tomato. With a gentle tug, the fruit should easily come off the vine.