How to Grow Tomatoes: Complete Guide
Tomatoes are among the most rewarding crops to grow, but they can also be demanding. They need warmth, light, reliable moisture, fertile soil and enough time for their fruit to develop and ripen.
Understanding how tomato plants grow makes their care much easier. The right variety, a suitable position and steady watering will prevent many of the problems that appear later in the season.
This complete guide covers the entire growing process, from choosing varieties and sowing seeds to pruning, harvesting and managing plants at the end of the season.
Choosing the Right Type of Tomato
Tomatoes are commonly divided into two main growing types: determinate and indeterminate. The difference affects how much space they need, how they should be supported and whether they require pruning.
Determinate Tomatoes
Determinate tomatoes, sometimes called bush tomatoes, grow to a naturally limited height. They usually produce most of their crop within a relatively short period.
They are often a good choice for:
Containers and smaller gardens
Shorter growing seasons
Gardeners wanting a concentrated harvest
Preserving, bottling or sauce-making
Determinate tomatoes generally need less pruning than indeterminate varieties. Removing too many side shoots or healthy leaves can reduce the size of the harvest because the plant has only a limited amount of growth available to support its fruit.
Although they are described as bush tomatoes, plants carrying a heavy crop may still need stakes, cages or another form of support.
Indeterminate Tomatoes
Indeterminate tomatoes, also known as cordon or vining tomatoes, continue growing and producing new flower trusses until cold weather, disease or deliberate pruning stops them.
They are well suited to:
Longer growing seasons
Greenhouses and polytunnels
Vertical growing
Gardeners wanting tomatoes over an extended period
These plants need strong support and regular tying as they grow. They can become very tall and may continue producing flowers long after there is enough time for the resulting fruit to ripen.
Indeterminate tomatoes are commonly trained as one main stem, although they can also be grown with two or more stems where there is sufficient room, airflow and support.
Choosing Varieties for Your Conditions
Tomato varieties differ greatly in their growth, flavour, fruit size, disease resistance and time to maturity.
When choosing a variety, consider:
The length and warmth of the growing season
Whether the plants will grow outdoors or under cover
The amount of available space
Whether the plants will grow in soil or containers
Local disease pressure
Whether an early, steady or concentrated harvest is preferred
The intended use of the fruit
Cherry tomatoes often ripen earlier and more reliably than large beefsteak varieties. Large-fruited tomatoes generally take longer to mature and may produce fewer fruits, even when the plants are healthy.
Days-to-maturity figures are useful for comparing varieties, but they are only estimates. Light levels, temperature, soil conditions and plant health can all affect when the first ripe fruit appears.
When to Sow Tomato Seeds
Tomatoes need a long growing season, but sowing too early can create weak, overcrowded plants before outdoor conditions are suitable.
Seeds are usually sown indoors around six to eight weeks before the plants can safely be moved to their final position. In colder climates or short growing seasons, they may be started slightly earlier under good growing lights. In warm climates, sowing dates may be adjusted to avoid periods of extreme summer heat.
Tomato seeds germinate best in warm conditions. A temperature of approximately 21–27°C is generally suitable.
Sow the seeds into moist seed compost and cover them lightly. Keep the compost consistently moist but not saturated. Once the seedlings emerge, move them into bright light.
Caring for Tomato Seedlings
Strong light is essential after germination. Seedlings grown with inadequate light stretch towards the light source and become tall, pale and weak.
Where natural light is insufficient, a grow light can help produce compact, sturdy plants. Seedlings also benefit from gentle air movement, which encourages stronger stems and helps prevent stagnant, excessively humid conditions.
Once the first true leaves have developed, seedlings can be transplanted into individual pots. Handle them by a leaf rather than by the stem, which is easily damaged.
If additional feeding is needed, use a suitable liquid organic feed at approximately half the normal strength. Young seedlings need gentle feeding rather than a concentrated fertiliser.
What to Do With Leggy Tomato Seedlings
Tomatoes are more forgiving of legginess than many other seedlings because they can develop roots along buried sections of stem.
When potting on a leggy seedling, place it deeper in the new container so that part of the stem is below the compost surface. New roots can form along the buried stem, helping the plant develop a stronger root system.
Do not bury the leaves. Remove only a lower leaf if it would otherwise sit below the compost.
Hardening Off Tomato Plants
Plants raised indoors indoors must be gradually accustomed to outdoor light, wind and changing temperatures before they are planted outside.
Begin by placing them in a sheltered, lightly shaded position for a short period. Increase their outdoor exposure gradually over several days, bringing them back under protection when conditions are too cold or severe.
Avoid moving tender plants directly from indoor conditions into strong sunshine. Leaves that have developed behind glass can scorch quickly.
Tomatoes should not be planted outside until the danger of frost has passed and night temperatures are reliably suitable. Prolonged exposure to cold can stop growth, damage foliage and delay the crop even when frost does not occur.
Where to Grow Tomatoes
Tomatoes perform best in a warm, bright position with good airflow and protection from damaging winds.
In temperate regions, they usually benefit from as much direct sunlight as possible. In extremely hot climates, some protection from intense afternoon sun may reduce heat stress and sunscald.
Avoid placing plants so close together that their leaves remain damp or airflow is severely restricted. Crowded plants are harder to inspect and may be more vulnerable to fungal and bacterial diseases.
Tomatoes can be grown in:
Garden beds
Raised beds
Greenhouses
Polytunnels
Large containers
Growing bags
Growing under cover provides protection from rain and can extend the season, but temperatures can become excessive. Ventilation is essential, particularly during flowering.
Preparing the Soil
Tomatoes grow best in fertile, moisture-retentive but well-drained soil. Adding mature compost before planting can improve soil structure, biological activity and water retention.
The aim is not to create excessively rich soil. Too much readily available nitrogen can produce large, dark-green plants with abundant leaves but relatively few flowers and fruits.
Avoid adding large amounts of high-nitrogen fertiliser at planting time. Balanced fertility is more useful than rapid, leafy growth.
Where possible, rotate tomatoes and related crops such as potatoes, peppers and aubergines with plants from other botanical families. Rotation cannot prevent every disease, but it may help reduce the build-up of some soil-borne problems.
Planting Tomatoes
Dig a planting hole large enough to accommodate the root system without forcing or tightly bending the roots.
Tomatoes can be planted deeper than they were growing in their pots. Roots may develop along the buried stem, producing a larger and more stable root system.
Remove any leaves that would be below the soil surface and bury the lower section of stem. Very leggy plants may be planted at an angle in a shallow trench, with the upper part of the plant gently brought upright. Take care not to bend or break the stem sharply.
Water the plant thoroughly after planting to settle the soil around the roots.
Tomato Plant Spacing
Correct spacing depends on the variety, the training method and the growing conditions.
Plants trained vertically as single stems can usually be grown closer together than unpruned bush plants. However, every plant still needs sufficient space for light and air to reach the foliage.
Overcrowding can lead to:
Poor airflow
Slower drying after rain or watering
Increased disease pressure
Excessive competition for water and nutrients
Reduced access for pruning, tying and harvesting
Follow the variety’s recommended spacing as a starting point, then adjust it to suit the training system and local climate.
Supporting Tomato Plants
Supports should be installed at or before planting so that roots are not damaged later.
Suitable supports include:
Strong stakes
Tomato cages
Trellis systems
Overhead strings
Frames or wires
Indeterminate plants need regular tying as they grow. Use soft ties and leave enough space for the stem to expand. Check older ties during the season because a tie that was loose in spring may cut into a thickening stem later.
Determinate plants may need less support, but branches carrying clusters of fruit can still bend or break.
How to Water Tomato Plants
Tomatoes need consistent access to moisture. The soil should not remain saturated, but repeated cycles of severe drying followed by heavy watering can cause stress and damage developing fruit.
Fluctuating moisture is associated with:
Blossom end rot
Fruit cracking and splitting
Flower drop
Reduced growth
Uneven nutrient uptake
Small or irregular fruit
Water deeply enough to moisten the root zone rather than repeatedly wetting only the surface. Allow the condition of the soil, the weather and the size of the plant to determine when more water is needed.
A useful check is to feel the soil approximately 5–8 centimetres below the surface. If it remains moist, watering can usually wait. If it feels dry at that depth, water thoroughly.
Water at the base of the plant where possible. Keeping foliage dry may help reduce the spread of some diseases, although outdoor leaves will naturally become wet during rain.
Morning watering is often preferable because plants have access to moisture during the day and accidental splashes on the foliage can dry more quickly.
Watering Tomatoes in Containers
Containers dry out more quickly than garden soil and may require daily watering during hot or windy weather. Small pots, dark-coloured containers and root-bound plants can dry especially rapidly.
Use a large container with drainage holes and water until moisture reaches the lower part of the compost. A small amount applied only to the surface may never reach the deeper roots.
Do not assume that a wilting plant always needs more water. Waterlogged roots can also cause wilting because they cannot function properly. Check the compost before watering again.
Mulching Tomato Plants
A mulch can reduce evaporation, moderate soil temperature and help prevent soil from splashing onto lower leaves.
Suitable materials include mature compost, leaf mould and other clean organic mulches. Apply mulch after the soil has warmed and contains adequate moisture.
Keep thick mulch from pressing directly against the main stem. Leaving a small clear area around the stem makes it easier to inspect the plant and reduces prolonged dampness at its base.
Feeding Tomatoes
Tomatoes are productive plants, but more fertiliser does not automatically mean more fruit.
A plant receiving excessive nitrogen may become tall and leafy while producing relatively few flowers. This is particularly common where rich manure or high-nitrogen feeds have been used heavily.
Before flowering, plants need balanced nutrition to establish healthy roots and foliage. Once flowering and fruiting are established, a fertiliser formulated for fruiting crops can be useful, especially for plants growing in containers.
Follow the product instructions rather than increasing the concentration in an attempt to accelerate growth. Overfeeding can damage roots, create nutrient imbalances and reduce fruit production.
Container-grown tomatoes depend almost entirely on the gardener for nutrients and usually require more regular feeding than plants growing in fertile garden soil.
Tomato Flowers and Pollination
Tomato flowers are self-fertile. Each flower contains both the male and female structures needed to form fruit, but movement helps release the pollen.
Outdoors, wind and visiting insects usually provide sufficient movement. Under cover, gently shaking the support or tapping the flower trusses can assist pollination.
Flowers may fall without producing fruit when plants are stressed by:
Very high temperatures
Cold nights
High humidity
Extremely dry air
Inconsistent watering
Inadequate light
Excessive nitrogen
Poor pollen release
Severe root or foliage stress
Daytime heat combined with warm nights can reduce pollen quality. Increasing ventilation, avoiding water stress and providing light shade during extreme heat may help. Once conditions improve, later flowers often set fruit normally.
Pruning Tomato Plants
Pruning should depend on the type of tomato and how it is being trained.
Pruning Indeterminate Tomatoes
Indeterminate tomatoes are often trained as a single main stem. Side shoots, also called suckers, develop where leaves join the main stem.
Removing selected side shoots keeps the plant manageable and directs growth into the chosen stems. Small shoots can usually be pinched out cleanly with the fingers. Larger shoots should be removed carefully with clean tools to avoid tearing the main stem.
Not every indeterminate plant has to be trained as a single stem. Two or more stems can increase the number of potential fruiting trusses, but they also require more space, support, water and airflow.
Pruning Determinate Tomatoes
Determinate plants should not usually be heavily pruned. Their stems and side shoots contribute to a crop that is produced within a limited growth period.
Remove only foliage that is:
Touching the soil
Yellowing naturally
Damaged
Clearly diseased
Preventing essential airflow
Unnecessary removal of healthy growth may reduce the final harvest.
Should Lower Tomato Leaves Be Removed?
Selective removal of lower leaves can be beneficial, particularly when the leaves touch the soil, remain damp, are badly damaged or show signs of disease.
Once the lowest fruit trusses are developing, a small number of leaves below them may also be removed to improve airflow and access for watering.
However, stripping large sections of healthy foliage is not helpful. Leaves manufacture the sugars that support plant growth, fruit development and flavour. They also shade tomatoes from intense sunlight.
Excessive leaf removal can:
Reduce photosynthesis
Slow fruit development
Weaken the plant
Expose fruit to sunscald
Increase heat stress
Reduce the eventual harvest
Remove leaves gradually—normally only two or three at a time—and allow the plant to retain a healthy canopy.
Should Indeterminate Tomatoes Be Topped?
Topping means removing the main growing tip to stop further upward growth.
It can be useful when:
The plant has reached the top of its support
It has become too tall to manage safely
The growing season is nearing its end
New flowers are unlikely to produce ripe tomatoes in time
The plant needs to concentrate on developing its existing fruit
Remove the growing tip approximately two leaves above the highest flower truss that is being retained. These leaves continue helping to feed and protect the developing fruit.
Topping too early will limit the number of flower trusses the plant can produce. A tall plant with few or small tomatoes may be suffering from heat, poor pollination, low light, irregular watering, excessive nitrogen or unsuitable variety choice. Removing the top will not correct those underlying problems.
Why Tomato Plants Produce Lots of Leaves but Little Fruit
Heavy foliage and poor fruit production are often blamed entirely on pruning, but several factors may be involved.
Common causes include:
Excessive nitrogen
Inadequate direct light
Temperatures that interfere with pollination
Inconsistent watering
Poor pollen release
Root restriction
Overcrowding
A naturally late or large-fruited variety
Flowers forming too late in the season
Look at the whole plant and its growing conditions before making major changes. Removing large quantities of foliage from a stressed plant can make the situation worse.
Preventing Blossom End Rot
Blossom end rot appears as a dark, sunken area at the end of the tomato opposite the stalk.
It is caused when developing fruit does not receive enough calcium. This does not necessarily mean the soil lacks calcium. More commonly, fluctuating soil moisture, root damage, excessive salinity or very rapid growth interferes with calcium uptake and movement through the plant.
The most useful preventive measures are:
Keep soil moisture reasonably consistent
Water deeply rather than little and often
Mulch to reduce rapid drying
Avoid damaging roots
Do not overfeed
Use containers large enough for the plant
Ensure containers drain properly
Adding calcium will not solve blossom end rot when calcium is already present but unavailable to the developing fruit because water uptake is irregular.
Affected fruit will not repair itself. It can be removed so the plant can direct energy towards new fruit, although lightly affected fruit may still develop usable, undamaged flesh.
Keeping Tomato Plants Healthy
Inspect plants regularly rather than waiting until damage is severe.
Look at:
The growing tips
The upper and lower leaf surfaces
The lowest leaves
Stems and leaf joints
Flower trusses
Developing fruit
The soil surface
Plant ties and supports
Environmental stress, physiological disorders, pest damage and disease can sometimes look similar. Before treating a plant, consider whether recent heat, cold, wind, water stress, feeding or physical damage could explain the symptoms.
Avoid automatically applying a pesticide or fungicide to every marked or yellow leaf. Correct identification prevents unnecessary treatment and makes it more likely that the real cause will be resolved.
Good routine care includes:
Providing adequate spacing
Watering consistently
Maintaining balanced fertility
Removing clearly diseased material
Keeping tools clean
Supporting stems securely
Avoiding unnecessary foliage damage
Checking plants frequently
Growing Tomatoes in Containers
Tomatoes can grow successfully in containers, but the container must be large enough to support the mature plant.
Large indeterminate varieties need substantially more root space than compact bush or patio tomatoes. A larger volume of compost dries more slowly and provides a more stable environment for the roots.
Container-grown tomatoes require particular attention to:
Regular watering
Drainage
Feeding
Root temperature
Strong support
Wind exposure
The mature size of the variety
Avoid allowing containers to stand in stagnant water for long periods. Equally, do not allow the compost to become repeatedly bone dry.
During severe heat, moving containers away from reflected heat or shading the container itself can protect the roots. Healthy foliage should normally remain exposed to sufficient light unless temporary protection from extreme conditions is necessary.
Growing Tomatoes Under Cover
Greenhouses and polytunnels can provide warmer conditions and protection from rain, but they require active management.
Open vents and doors to maintain airflow and prevent excessive temperatures. High heat can stop flowers setting fruit even when the plants appear vigorous.
Covered plants depend entirely on the gardener for water. Check the soil regularly and remember that a large plant can remove considerable moisture from the ground each day.
Humidity that remains high for long periods can encourage disease and interfere with pollen release. Good ventilation, suitable spacing and watering at soil level can help maintain a healthier growing environment.
Harvesting Tomatoes
Tomatoes usually develop their best flavour when allowed to ripen on the plant, provided weather, pests and disease allow this.
A ripe tomato should have developed the expected colour for its variety and should yield slightly when gently pressed. Some varieties remain green, striped, purple or dark-coloured when ripe, so colour alone is not always a reliable guide.
Pick fruit carefully to avoid damaging the truss or tearing the stem. Frequent harvesting encourages the gardener to inspect the plants and reduces the risk of overripe fruit splitting or attracting pests.
Tomatoes that have begun changing colour can continue ripening after picking. This can be useful when fruit is at risk from heavy rain, frost, pests or advancing disease.
End-of-Season Care
As the end of the growing season approaches, remove new flowers and very small fruit that have little chance of reaching maturity. This allows the plant to direct its remaining resources towards fruit that is already developing.
Indeterminate plants may be topped several weeks before conditions are expected to become too cold for growth. Continue removing clearly diseased leaves, but retain enough healthy foliage to support and protect the remaining crop.
Before frost or severe cold arrives, harvest mature green tomatoes. Undamaged fruit can ripen indoors in a dry, well-ventilated place. Check stored fruit regularly and remove any showing signs of decay.
Healthy plant material can be composted. Plants affected by serious disease should be handled according to the disease involved and the composting system available, because some pathogens can survive incomplete composting.
Clean reusable supports, pots and tools before the next tomato-growing season.
The Foundations of a Healthy Tomato Crop
Successful tomato growing does not depend on constant intervention. Most plants perform well when a few essential needs are met consistently:
Choose a variety suited to the available space and climate
Provide warmth and sufficient light
Plant into fertile, well-drained soil
Support plants before they become heavy
Water deeply and consistently
Feed according to the plant’s needs
Prune according to its growth type
Retain enough healthy foliage
Protect flowers from extreme heat where possible
Inspect plants regularly
Harvest fruit as it ripens
Tomatoes will not always look perfect. A few curled leaves, marked fruits or failed flowers do not necessarily mean the crop is being lost. Observe the whole plant, consider recent conditions and make measured changes rather than reacting to a single symptom.
Steady care, accurate diagnosis and an understanding of how the plant grows provide the strongest foundation for a healthy and productive tomato crop.
