TOMATO GROWING TIPS
Fruit or Vegetable
The tomato is legally declared a vegetable by the Supreme Court of the United States. A
vegetable is an herbaceous (non-woody) plant or plant part which can be eaten without
processing and is usually consumed with the main meal. (Nix v. Hedden; May 10, 1893).
When to Start Tomatoes from Seed
It takes at least 6 to 8 weeks to grow transplants. If you want longer stems to plant deep, start
a little earlier. Planting depends on the weather and soil temperature.
Tomato Terminology
Varieties that are disease resistant will have one or more letters on the name tag.
V= Verticillium Wilt
F= Fusarium Wilt
T= Tobacco Mosaic Virus
A= Alternaria (Crown Wilt)
N= Nematodes
L= Septoria Leaf Spot
Determinate plants will grow to a certain height and produce fruit at one time. Harvest time is
short and most plant growth stops when the fruit has set. This type plant forms flower clusters
at the terminal growing point, causing the plant to stop growing.
Indeterminate plants keep producing fruit and blossoms after the first fruit has set. Tomatoes
in all stages of development may be on the plant at once and the harvest is extended. These
will continue to grow in height and produce fruit until frost hits the plant. These plants never
set terminal flower clusters, only lateral ones and will continue to grow taller.
Days to fruit usually means days to maturity after the young transplants have been set into the
garden. These plants will have been started 6 to 8 weeks before they are planted in the garden.
United States Department of Agriculture · Local Extension Councils Cooperating
University of Illinois Extension provides equal opportunities in programs and employment.
Garden Location
The garden location needs at least 6 to 8 hours of sunlight a day. Do not plant tomatoes where
they will be shaded by buildings, trees or taller plants such as corn.
Soil
Tomatoes do best in loose, rich, well-drained soil. Be sure to work lots of compost into your
garden before planting. Have a soil sample tested every 3 to 5 years, after you get a good
reading on a sample. Tomatoes need a PH of 5.5 to 7.5
Planting
Tomatoes like warm soil and do not tolerate frost. Wait until warm spring days arrive and soil
temperatures reach above 60 degrees Fahrenheit to plant. Pinch off the branches below the
top 2 or 3 branches and plant with these branches above ground. Bury the plant’s stem 6 to 8
inches deep and it will sprout new roots that help the plant grow sturdy and tall quickly. Press
the soil down gently. When the hot dry summer hits, the tomato roots will be in cooler, moist
soil. It is best to plant tomatoes in the cooler part of the day. Spacing depends on the tomato
variety and method of culture. Space dwarf plants 12” apart, staked plants 15” to 24” apart,
and trellised or ground bed plants 24” to 36” apart. Some vigorous varieties may need 4’
between plants for easy harvesting. Do not crowd plants when setting out in the garden. If you
plant for yield, plant close together. If you want large tomatoes, give them space.
Watering
Once your plants are in the ground water them well. To avoid disease problems water at the
base of the plant and early in the day. Tomatoes need even moisture so do not let your garden
dry out. Wait 4 to 5 weeks after planting when the ground temperature is over 65 degrees
Fahrenheit and the plants are established before applying a thick layer of mulch. The warmer
the soil before applying mulch the better. Use straw, dry untreated grass clippings, pine
needles, compost or shredded leaves. Do not use saw dust or wood chips. Mulching will retain
moisture in the soil, keep the plant’s roots cooler and prevent weeds. Keep the mulch 6 to 8
inches away from the plant stem to allow for watering.
Rotate Your Crops
Put your tomatoes on a 3-year rotation schedule. This will break the disease cycle. Make sure
you do not plant your tomatoes in a place that other members of the tomato family (eggplant,
potatoes, and peppers) have grown in the past 3 years. There is no way to “cure” a virus
infected plant. The plant should be removed as soon as the symptoms are found to help
prevent the spread to healthy plants. Insects spread tomato virus, but moist air and wind will
spread the fungus for early blight and other blights.
2
Fertilizing
As long as you have added compost to your garden before planting you should not need to add
any other fertilizer for tomatoes. Use your soil sample as a guide. Tomatoes thrive in soil that
is rich in humus for extensive well nourished root systems and potassium for strong stems. Add
too much nitrogen and you will have big lush plants with very little fruit. Overload the garden
with manure and you will get fewer tomatoes and more weeds. Compost usually supplies all
the phosphorus your tomatoes need for good flowering and fruiting. You may want to apply
starter fertilizer when transplanting. Side-dress with about 1 tablespoon 10-10-10 fertilizer per
plant after tomatoes has grown to the size of golf balls. Make 2 more applications 3 to 6 weeks
later. Liquid fertilizers have a greater risk of burning plants if the liquid formulation is applied at
the wrong rate. Do not get fertilizer on the leaves.
Pruning
When the tomato has grown to approximately 12 inches tall, remove lower branches and
suckers. Removing lower branches keeps the leaves from touching the ground and prevents
soil from being splashed upon the plant when it rains. This will help prevent any soil borne
disease from getting on the plant. Picking the first flowers will allow the plant to grow deep,
extensive roots and a full leaf canopy to help establish healthy plants early. Remove suckers
from indeterminate varieties. Suckers are the part of the plant that sprouts in the fork between
the stem and branches. It is not necessary to remove suckers from determinate plants.
Cage Your Plants
Tomatoes grow best when they are grown upright. Concrete reinforcing wire makes good 5
foot tall tomato cages. The wire is 5 feet wide and has 6 inch squares. A stake is driven in the
ground and the tomato cage is fastened to it for support. Tomato vines left to sprawl on the
ground are more susceptible to attacks by pests and diseases. They also take up more growing
area and the tomatoes are harder to harvest. Staked or caged tomatoes also allow air
circulation to help prevent diseases.
Pests
Cutworms - If the plant stems are being chewed off, you might have cutworms. If cutworms are
a problem in your garden a Popsicle stick placed next to the tomato plant when planted will
keep the cutworm from encircling the plant.
Tomato Hornworms - If you notice holes in the leaves of your tomato plants or large green
worms on your plants, you probably have tomato hornworms. Hand pick and squash the
worms but spare those that carry the white cocoons of parasitic wasps on their backs. The
wasps are their natural predators.
Stink Bugs - Leave white knots inside of tomatoes. Early control of sucking insects that feed on
the fruit is helpful in alleviating the problem.
3
Aphids - Look like pinhead-size bumps. When they are present, the plant dehydrates even if
you water every day. Leaves do not expand fully and fruit production may be compromised.
Look for honeydew (sticky substance on the leaves).
White Flies - Similar damage as aphids but their presence is easier to detect since they fly away
when you touch the plant. Best time to control is just before dusk.
Spider Mites - Dehydrates green plant material but damages it discretely. You will know when
they are around when leaves look stippled, as if someone pricked them with a pin. The leaves
may discolor and flowering usually stops. Look for fine webbing under the foliage as a sign of
spider mites.
Birds - Usually looking for the moisture in the plant. Protect the plant so the birds cannot get to
them. Four inch diameter by twelve inch tall clay tile will offer protection from birds and cold.
Plant Diseases
Early Blight - Caused by a fungus that survives the winter on old vines and garden debris.
Remove diseased foliage from the plant and dispose of it. Avoid crowding plants and prune for
good air circulation. Rotate crops. Usually starts at the bottom of plant and works its way up.
Wet foliage, high humidity and poor circulation around the plants contribute greatly to this
problem. Look for concentric rings or target like spots on leaves.
Anthracnose - Caused by a fungus that attacks the fruit. First symptoms become visible on ripe
fruit as small, circular indented spots in the skin. These spots expand and develop dark centers
or concentric rings of dark specks which are the spore producing bodies of the fungus. These
bodies produce a large number of spores giving diseased areas a cream to salmon-pink color.
Wilt - Fusarium and Verticillium fungi cause branches to wilt and can kill the plant over time.
Look for resistant varieties. Rotate crops. Southern bacterial wilt results in sudden plant death.
Remove all debris and do not plant tomatoes where the disease has occurred in the past.
Late Blight - Caused by a fungus that is favored by wet weather. Spores travel great distances
and can cause plants and fruit to suddenly rot. Starts as purplish or black water soaked spots
on lower leaves. Avoid crowding plants if the infection is severe and wide spread, remove and
destroy all affected plants to prevent spread of the disease.
Bacterial Speck or Spot – Black spots surrounded by yellow halo on leaves and fruit are typical
of bacterial speck. With bacterial spot, the spots are water soaked with an irregular shape. To
control bacterial diseases, pick off infected leaves, water at base of plant and don’t get water
on the leaves. Do not touch plants when they are wet.
Root Knot Nematodes - Microscopic eelworms that live in soil and cause stunted growth.
4
Dispose of Diseased Plants
Do not compost plants with diseases because you risk spreading the disease to the rest of your
garden. Throw away diseased plants and any garden debris (mulch, weeds, etc.) that came in
contact with them. Remove all tomato plants in the fall and dispose of them away from the
garden.
Symptoms That Are Not Diseases
Cracking - Many tomatoes crack after heavy summer rains and there is not much you can do
about it. Just remember to pick all ripe tomatoes before it rains. Mulch and watering can help
but some kinds of big tomatoes are prone to cracking. These cracks typically scar over and do
not affect taste.
Catfacing - Caused by incomplete pollination in cold weather. Do not plant too early.
Blossom End Rot - Caused by poor calcium uptake due to inconsistent moisture. Provide
consistent moisture and keep a layer of mulch on the soil.
Leaf Curl - A sign of stress. If the older leaves are curling, this is not a concern. Tomatoes often
do this as summer temperatures rise. Some varieties are more prone to this than others and
high fertility levels increase the condition. Too much rain can cause wilting if the soil does not
drain adequately. Water logged soil prevents oxygen from getting to the root system and can
result in root loss and wilting of the plant.
Sun Scald - Caused by removing too much leaf growth and exposing the tomato fruit to being
sunburned.
Curling and Twisted Leaves – May be herbicide drift from other parts of your yard or your
neighbor’s. Some herbicides act as a growth hormone and cause the plant’s leaves to grow
rapidly, causing distortion. It is not advisable to consume tomatoes from these plants, even if
the plants don’t die. Remember though, that leaves may curl naturally when the weather is hot.
When in doubt, bring a sample of the affected plant to your local U of I Extension office for
assistance.
Weather
Chilly spring temperatures (nights cooler than 50 degrees Fahrenheit) slow tomato plants
growth. Hot summer temperatures (days hotter than 95 degrees Fahrenheit) cause the
flowers to fall off. You can moderate cool extremes with Wall O’ Water. They also protect from
high winds. Pollen is inhibited when nights are above 73 degrees Fahrenheit.
Harvest
For best flavor, harvest tomatoes when they are firm and fully colored. Fruits will continue to
ripen if you pick them when they are half-ripe and bring them indoors out of the sunlight. The
flavor is often better if you allow fruit to ripen on the vine. Place 4 tomatoes in a paper sack
with 1 apple and the tomatoes will ripen in about 36 hours. Gently twist the fruit off while
5
holding the vine. Remove the stem from the tomato before placing them in a bucket to keep
the short stem from poking holes in other tomatoes. Do not store tomatoes in the refrigerator
because the cold temperature will cause them to lose flavor and texture. Place tomatoes in a
refrigerator a couple hours before eating if you prefer cool tomatoes.
What You Can Add to Your Garden to Improve the Soil
Compost - Helps to loosen the soil and helps retain moisture.
Coffee Grounds - Adds nitrogen. Since they are mildly acidic, they balance the alkaline of wood
ashes. Adding brown material such as leaves and dried grass will help keep a balanced PH.
Leaves - Loosens soil and helps retain water. Shredded leaves make good mulch. Leaves will
improve the soil if it is clay or sandy.
Egg Shells - Adds calcium to the soil. Helps prevent blossom-end rot.
Banana Peels - Adds potassium.
Pine Needles - Makes good compost or use as mulch.
Grass Clippings - Makes good compost or use as mulch.
Shredded Papers - Use as mulch. You may want to cover with a layer of shredded leaves to
improve the appearance of the garden. Newspaper can also be used and covered with leaves.
Do not use colored paper that might contain non-biodegradable coatings or heavy metals.
Ingredients for Compost
Raw materials from the garden, grass clippings, sod, leaves, corn stalks, hedge clippings,
discarded plants, shredded twigs and branches combine to make good compost. Kitchen
scraps, such as fruit and vegetable trimmings, egg shells, and coffee grounds can be added to
make compost. Do not add grease, fat, meat or bones to any compost. These items will draw
pests. If any weed seed or diseased plants are added to the compost pile, it has to heat to 140
to 160 degrees to kill them.
PH
7.0 is the neutral point. Below 7 is increasing acidity as the number gets smaller; while above 7
is increasing alkalinity. Lime is added to increase PH (alkaline or sweet) and sulfur to decrease
PH (acid). A test of 6.9 is 10 times more acid that a test of 7.0.
Nitrogen
(N) Promotes leafy top growth. Soil nitrogen is usually present from decomposing plant
material.
6
Phosphorus
(P) Promotes root growth, flowers, and fruit production.
Potassium
(K) Sometimes called potash. Improves general durability, promotes disease resistance, and
cold hardiness.
Organic Matter or Humus
Humus is the end product of organic matter breakdown and is usually associated with the dark
color in top soils. Humus is needed to maintain a loose, well-drained soil that does not compact
easily. Soil containing good quantities of humus will cultivate easily and will promote good root
growth. Humus is also useful in supplying nutrients to plants, particularly nitrogen. A very
important point is you must keep adding partially decomposed plant material to the garden
each season in order to improve its tilth and fertility. Good materials to use include compost,
peat moss, and well-rotted manure from horses, cows, goats, sheep, rabbits, and poultry. Do
not use fresh manure on the garden. Do not use cat, dog or human waste that may contain
pathogens that could be harmful. Also, do not use anything that you can’t be sure is free of
chemical pesticide or herbicide residue. With careful attention to the composition of organic
additions to compost (such as cottonseed meal, blood meal 12-0-0, bone meal 4-12-0, super
phosphate 0-18-0, wood ashes, and manure) gardeners can achieve good results without the
use of commercial inorganic fertilizers.
Prepared By:
Richard Zerfowski
Macon County Master Gardener
7