of Rhode Island GreenShare Factsheets
One of the most popular of all home garden vegetables is the tomato. Originating
in Central and South America, the tomato was thought by early American
colonists to be poisonous and was not recognized as a useful vegetable
until the 1800s. Eaten raw or in innumerable cooked dishes, today the tomato
is an almost daily part of the American diet. When grown as staked plants,
tomatoes require a relatively small amount of space, yet are capable of
producing 8 to 10 pounds or more of fruit per plant. Tomatoes are low in
calories and a good source of vitamin C.
Tomatoes are warm-season plants and should be planted only
after danger of frost has passed. Temperature is an important
factor in the production of tomatoes, which are particularly
sensitive to low night temperatures. Blossom drop can occur in
early spring when daytime temperatures are warm but night temperatures
fall below 55 degrees F, as well as in summer when days are above
90 degrees F and nights above 76 degrees F.
Tomatoes can be grown on many different soil types, but
a deep, loamy soil, well-drained and supplied with organic matter
and nutrients is most suitable. As with most garden vegetables,
tomatoes grow best in a slightly acid soil with a pH of 6.2 to
Tomatoes respond well to fertilizer applications, especially
phosphorus. Excess nitrogen fertilizer can result in plants with
extremely vigorous vine growth but little fruit production. Apply
2-1/2 to 3 pounds of a complete fertilizer, such as 5-10-10,
5-20-20 or 8-16-16 per 100 square feet of garden area. Work the
fertilizer into the soil about 2 weeks before planting. An additional
sidedressing of a nitrogen fertilizer may be desirable after
the first cluster of flowers have set fruit.
There are probably more tomato cultivars available to the
home gardener than any other garden vegetable. When choosing
cultivars, keep in mind the different ripening periods. Tomatoes
are usually categorized as early, mid-season or late. Another
consideration is whether the tomato cultivar you choose is determinate
or indeterminate in growth habit. Determinate (D) tomato plants
grow to a certain height and then stop. They also flower and
set all their fruit within a relatively short period of time.
This is an advantage if the tomatoes are being grown primarily
for canning purposes. Indeterminate tomato plants grow, flower
and set fruit over the entire growing season. Another characteristic
to look for when choosing tomato cultivars is disease resistance.
Many cultivar names are followed by one or more letters indicating
resistance to Verticillium wilt (V), Fusarium wilt (F) or nematodes
(N). Disease resistance can be an important consideration, especially
if you have experienced these problems with tomatoes in the past.
Due to their long growing season and temperature requirements,
tomatoes are set out as transplants in gardens in the Northeast.
Tomatoes may be planted anytime after the last spring frost date.
When purchasing tomato transplants, choose those with straight,
sturdy stems about the thickness of a pencil. They should have
4 to 6 young true leaves, no blossoms or fruit and be free of
insect pests and diseases.
Plants in individual containers or cell packs experience
little or no transplant shock and become established quickly.
Tomato plants will develop roots along the stem and may be set
deeply at transplanting with the first set of leaves near the
soil surface. If transplants are in peat pots, remove the rim
of the pot or be sure the rim is below the soil surface so that
the soil ball will not dry out.
A soluble starter fertilizer high in phosphorus can be applied
at planting time. Use according to label directions.
Tomatoes grown unstaked are usually planted 3 feet apart
in rows 5 feet apart. Plants to be staked are planted 2 feet
apart in rows 3 to 4 feet apart. Plants to be caged are planted
30 to 36 inches apart. Stakes and cages should be placed at planting
time or soon after so as to not disturb the roots. Unstaked plants
should be mulched with clean straw, black plastic or another
suitable material to keep the fruit off the ground and prevent
Where space is limited or soil conditions poor, tomato plants
can be grown in containers using a disease-free planting mix.
Any container with adequate drainage is suitable. Pay special
attention to water and fertilizer needs of container-grown tomato
Once the tomato plants are established, apply a mulch to
conserve moisture and suppress weed growth. If weeds do appear,
they may be pulled by hand or removed by shallow cultivation.
An even moisture supply is important, especially once the tomato
fruits begin to develop. If the soil becomes too dry, blossom-end
rot can be a problem. If too much water is applied at one time,
ripening fruit may split.
Staked plants are usually pruned
to a single or double stem and periodically tied loosely to
the stake with soft twine. Pruning
is accomplished by removing all the branches or "suckers" that
grow from the leaf axils, leaving only the main stem or the main
stem and one additional branch near the base. Unsupported and
caged tomatoes may be left to branch normally. Staked and pruned
tomatoes produce fewer but larger fruit than caged or unsupported
Adapted from Marianne Riofrio,
Ohio State University Extension, 2000
are poisonous! Read and follow all safety precautions on labels.
Handle carefully and store in original containers out of reach
of children, pets or livestock. Dispose of empty containers
immediately, in a safe manner and place. Pesticides should never
be stored with foods or in areas where people eat.
When trade names are used for identification, no product endorsement
is implied, nor is discrimination intended against similar materials.
Be sure that the pesticide you intend to use is registered for
the state of use.
The user of this information assumes all risk for personal injury
or property damage.
information, call the URI CE Gardening and Food Safety Hotline
at 1-800-448-1011 or (401)874-2929 from outside Rhode Island;
Monday-Thursday between 9 am and 2 pm.
of Rhode Island Cooperative Extension provides equal program