A Little Background on the Tomato Plant
The tomato Solanum lycopersicum is native to South America and is a member of the nightshade family of plants.
Following colonization of the Americas the Spanish introduced tomatoes to many of their other colonies such as the Philippines and the Caribbean islands. They also introduced the plant to Europe, where it flourished and quickly became a mainstay of many Mediterranean dishes.
Today the tomato is grown throughout the world and over 130 million tonnes are produced commercially per annum.
There are at least 7,500 different varieties available and tomato plants bear fruits ranging in size from two-tenths of an inch (5mm) to 4 inches (10cm) in diameter. Although most types of tomato fruits are red, other colors are fairly common, especially yellow and orange (other fruit colors include white,pink, brown, black and purple).
Sowing Tomato Seeds
Depending upon your location you may choose to grow your tomatoes indoors, in a greenhouse or outdoors. If growing outdoors it is best to begin the plants indoors and transplant outside once soil temperature has reached 15 degrees Celsius/ 60 degrees Fahrenheit. Plan to start off your tomatoes about eight or nine weeks before you expect the soil to reach this temperature. In many temperate regions the ideal time to sow tomato seeds is March through to April.
Initially you should fill a three inch (8 cm) pot(s) with a soil mix (see below) or compost, firm it with your hand and then water the soil in the pot. Sow the seeds thinly on the surface. Next spread a thin layer of vermiculite on top of the seeds to cover them.
The pot(s) should then be placed into a warm draft free area, an airing cupboard is ideal for this purpose; be sure to keep the soil moist. Once seedlings have emerged, the pot(s) should be transferred to an area of light such as your windowsill (do not put into a place of direct sunlight as this may result in scorched leaves) or the greenhouse.
Nb. You will find that most tomato seeds germinate so you only need to sow a few extra seeds than the number of plants that you require.
Soil/Soiless mix
It is best to sow seeds in a soiless potting mix and then transplant the tomato seedlings into an ideal growth medium at a later stage; this should consist of 50% soil (clay or sandy), 35% peat moss and 15% compost. Studies have shown that tomatoes growing in a mixture that is 70% soil and 30% compost tend to under perform.
Transplanting Tomato Plant Seedlings
As tomato plants do not thrive competition it is best to transplant seedlings into individual four inch (10 cm) compost pots once they have reached the two leaf stage. After around eight weeks growth the tomato plants will be ready to be transferred to their final location, be it outside or in the greenhouse. Transplant when they are about 6 inches (15 cm) in height.
Ideally the area where you plan to grow the tomatoes will be in the warmest part of the garden, this is often close to a wall where the heat of the house will help to keep the soil warm. It should also be in an area of the garden that receives plenty of sunlight. Before you transplant you should drive a stake/cane into the ground about 2 inches (5 cm) from where you plan to grow the plants, this will be used to support the plant as it grows.
Caring for Tomatoes During the Growing Season
As the plant grows it will require support so tie it to the stake/cane at about four inch / 10cm intervals.
With the exception of bush tomatoes you should plan to grow your plants as a single stem; to do this you should cut or snap off shoots that grow out of the stem/leaf joints. Once the plant has produced four sets of flowering trusses you should cut off the growing tip (Shoot apical meristem) of the plant. This will allow all of the plants energy to be directed into flowering/fruit growth.
Tomato plants are thirsty and hungry; they should be watered daily and it is important to fertilize them once a week with a tomato specific fertilizer to ensure that the plant gets enough nutrients to produce high quality fruits.
Pollination of Tomato Plants
Tomato plants are able to both cross and self fertilize. In Ideal conditions the presence of bumble bees and summer breezes will ensure that tomato flowers get fertilized and bear fruit. However if you live in an area with little wind and few bumble bees, or are growing tomato plants in the greenhouse then you may want to help with the fertilization process. The best way to do this is to mimic the vibration of a bumble bee by using an electric toothbrush or razor (blade removed of course). Hold the toothbrush next to the stem at the base of the flower and vibrate the plant. Alternatively you can help the fertilization process along by using a small soft bristled brush, shaking the plants, or mimicking wind by blowing on the plants. For best results do this three times a week during the flowering period.
This article is an excerpt from the PBA Tomato Growing Guide. If you want to see the full article, which includes tips on harvesting of tomatoes; how to grow tomatoes in the greenhouse; and use of growbags then you can get this ebook for free by signing up to our gardening newsletter.