There’s something magical about slicing into a sun-warmed, homegrown tomato, nothing in the grocery store compares. But growing tomatoes successfully can be tricky if you don’t know what to watch out for.
Whether this is your first time growing tomatoes or you’ve been disappointed by small harvests or sad plants in the past, let’s walk through 10 common tomato growing mistakes gardeners make, and how to avoid them, so you can grow your best tomatoes yet.
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1. CHOOSING THE WRONG TOMATO VARIETY FOR YOUR SPACE AND GOALS
One of the first (and most important) decisions you’ll make is which tomato varieties to grow. Not all tomato plants will thrive in your garden setup, and picking the wrong type can lead to frustration later in the season.
There are two main types of tomato plants:
DETERMINATE (BUSH)
These grow to a certain size (usually 2–4 feet tall), produce most of their fruit at once, and then taper off. They’re great if you want a big harvest for canning or sauce-making and if you have limited space. They’re also ideal for containers and raised bed gardens.
INDETERMINATE (VINING)
These keep growing and producing fruit throughout the season until frost. They require staking, trellising, or caging to support their long vines (which can reach 6 feet or more!). Perfect for gardeners who want a steady supply of fresh tomatoes all season long.
PRO TIP: Always check the plant tag or seed packet to see which type you’re buying before planting.
You will also want to consider the following before picking what type of tomatoes you should grow:
SIZE OF FRUIT
Do you want tiny, snackable cherry tomatoes or big, juicy slicers? Cherry and grape varieties tend to be easier for beginners and more prolific.
DAYS TO MATURITY
If you have a shorter growing season, look for early-producing varieties like Early Girl, Glacier Bush, or Sungold.
DISEASE RESISTANCE
Look for varieties labeled with letters like V (Verticillium), F (Fusarium), or N (Nematodes) for built-in resistance to common problems.
YOUR GARDENING SPACE
Large indeterminate varieties need plenty of root space, sunlight, and support, while smaller determinate varieties are easier to manage in containers or tight spaces.
👉 Learn more about Growing Tomatoes in Containers.
EXAMPLES OF TOMATO VARIETIES BY TYPE:
DETERMINATE
Bush Early Girl, Roma, Celebrity, Tiny Tim
INDETERMINATE
Juliet, Sungold, San Marzano, Cherokee Purple, Brandywine, Beefsteak
2. NOT GIVING YOUR TOMATOES ENOUGH SUNLIGHT
Tomatoes thrive in the spotlight, literally. They need lots of direct sunlight to grow strong, produce flowers, and ripen fruit. If they don’t get enough light, they’ll stretch toward the sun, become leggy, and struggle to produce much of anything.
This is one of the most common reasons gardeners end up with beautiful plants but little to no harvest.
HERE’S WHAT TOMATOES REALLY NEED:
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6 to 8+ hours of direct sunlight per day (the more, the better)
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A sunny, unobstructed spot, away from shade cast by buildings, trees, or fences
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In containers, the flexibility to move your plant to chase the sun if needed
WARNING SIGNS OF TOO LITTLE LIGHT:
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Pale, leggy stems
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Few flowers or fruit
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Long internodes (space between leaves)
PRO TIP: Track how the sun moves across your garden or patio during the day. Even a few extra hours of sunlight can mean a bigger harvest.
3. PLANTING IN POOR SOIL (or Skipping Soil Prep Altogether)
Tomatoes are heavy feeders, which means they need rich, fertile, and well-draining soil to grow big and produce lots of fruit. Planting them in tired, compacted, or nutrient-poor soil is a recipe for weak plants and disappointing harvests.
If you’re planting in the ground, soil prep is everything. And if you’re growing in containers, the quality of your potting mix makes a huge difference.
SIGNS YOUR SOIL MIGHT NOT BE UP TO PAR:
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Water pools on the surface or drains very slowly
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Leaves turn yellow or pale green
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Plants grow slowly or produce very few tomatoes
THE IDEAL TOMATO SOIL SHOULD BE:
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Light and fluffy (good drainage)
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Rich in organic matter (like compost)
- Full of life (earthworms are a good sign!)
FOR RAISED BEDS OR IN-GROUND PLANTING:
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Mix in a generous amount of compost before planting
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Add a handful of slow-release organic fertilizer
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Consider tossing in crushed eggshells or a tomato-specific fertilizer that includes calcium to help prevent blossom end rot
- Read more about the ideal raised bed soil mix here.
FOR CONTAINERS:
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Use a high-quality potting mix designed for vegetables, don’t use garden soil, which is too dense
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Mix in compost or worm castings to boost nutrition
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You can also add perlite or coconut coir to help improve drainage
- Read more about growing tomatoes in containers here.
PRO TIP: If you’ve grown tomatoes in the same soil for a few years, rotate them to a new spot or refresh your container soil. Repeated planting in the same place can lead to nutrient depletion and a buildup of soil-borne diseases.
4. USING A CONTAINER THAT’S TOO SMALL
Tomato plants might start out looking small and manageable, but they grow fast, and their roots need plenty of space to spread out if you want healthy, productive plants.
One of the most common mistakes new gardeners make is planting tomatoes in containers that are too small. This can lead to:
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Stunted growth
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Yellowing leaves
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Poor fruit production
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Plants drying out too quickly between waterings
MINIMUM TOMATO GROWING CONTAINER SIZE:
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5 gallons for compact or determinate tomato varieties
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7–10 gallons (or larger!) for indeterminate varieties
Tomatoes grown in undersized pots will quickly become root-bound, meaning the roots circle tightly and can’t absorb nutrients or water efficiently. Plus, small pots dry out faster, which means more stress for your plant, and more work for you.
THE BEST CONTAINERS FOR TOMATOES:
*Make sure your container has at least one good drainage hole, no soggy roots, please!*
1. GROW BAGS: (10–15 gallons)
Breathable and space-saving
2. FOOD-SAFE PLASTIC POTS OR BARREL
Lightweight and durable
3. GLAZED CERAMIC OR TERRACOTTA POTS:
Attractive and stable (just ensure they have good drainage)
**Best purchased at your local nursery store due to heavy shipping costs.
4. RAISED BEDS:
An excellent option if you have the space
PRO TIP: Place a tomato cage, stake, or trellis in the container before your plant starts growing tall. Trying to add support later often disturbs the roots.
5. WATERING TOMATOES INCONSISTENTLY
Tomatoes are a bit dramatic when it comes to water. Too much, and they’re prone to root rot and fungal diseases. Too little, and the fruit cracks, drops prematurely, or develops blossom end rot. Inconsistent watering is one of the top reasons gardeners struggle with tomato problems.
Tomato plants like their soil to be consistently moist, not soggy and not bone dry.
HERE’S WHAT INCONSISTENT WATERING CAN LEAD TO:
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Cracked or split tomatoes
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Blossom end rot (that sunken black spot on the bottom of the fruit)
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Leaf curl or wilting
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Stressed plants that are more vulnerable to pests and disease
So, how often should you water?
It depends on your climate, the size of your plant, and whether you’re growing in the ground, a raised bed, or a container. But in general:
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In-ground and raised bed tomatoes: Water deeply 2–3 times a week
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Container tomatoes: Water daily (or even twice a day in hot weather) since pots dry out faster
The goal is to water deeply enough that the moisture reaches the entire root zone.
WATERING TIPS FOR SUCCESS:
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Water in the morning so leaves dry quickly—this helps prevent fungal diseases
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Water at the base of the plant, not over the leaves
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Use mulch (like straw or shredded leaves) to help retain moisture and reduce evaporation
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Stick your finger in the soil—if the top 1–2 inches are dry, it’s time to water
PRO TIP: Set up a simple drip irrigation system with a timer for easy, consistent watering. Avoid watering the leaves of your tomato plants to help prevent fungal issues.
👉READ MORE: Best Tips for Watering Your Tomato Plants
6. SKIPPING SUPPORT FOR YOUR TOMATO PLANTS
Tomatoes might start out looking small and upright, but as they grow, they become heavy with foliage and fruit, and without support, they’ll sprawl on the ground. This makes your plants more vulnerable to pests, diseases, and fruit rot.
Even determinate (bush-type) tomatoes benefit from some light support to keep them upright and tidy. Indeterminate (vining) varieties absolutely need sturdy support to grow vertically.
WHY TOMTATO SUPPORT IS ESSENTIAL:
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Keeps fruit off the soil, reducing the risk of rot and pests
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Increases airflow around the plant, which helps prevent fungal diseases
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Makes harvesting easier and cleaner
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Helps the plant direct energy into fruit production instead of sprawling
POPULAR TOMATO SUPPORT OPTIONS:
1. TOMATO CAGES:
Great for determinate varieties; choose strong, wide ones that won’t topple
2. STAKES:
Simple and space-saving; tie the plant loosely to the stake as it grows
3. TRELLISES:
Ideal for raised beds and indeterminate varieties; keeps your garden looking beautiful and maximizes your vertical growing space. Shop LGS trellises here!
PRO TIP: Whatever system you choose, install it at planting time. Trying to add support later can disturb the roots and damage the plant.
7. NOT FERTILIZING TOMATOES (or Fertilizing the Wrong Way)
Tomatoes are hungry plants. They need a steady supply of nutrients to grow healthy leaves, develop strong stems, and produce juicy, flavorful fruit. Unfortunately, many gardeners either forget to fertilize entirely or go overboard with the wrong kind of fertilizer, both can lead to disappointing results.
WHAT HAPPENS WHEN YOU UNDER-FERTILIZE:
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Slow or stunted growth
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Pale or yellowing leaves
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Few flowers and little to no fruit
WHAT HAPPENS WHEN YOU OVER-FERTILIZE:
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Lots of leafy green growth but few tomatoes
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Leaf tip burn or curled foliage
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Salt buildup in the soil, especially in containers
BEST TOMATO FERTLILIZING STRATEGY:
Start with healthy, compost-rich soil, and then supplement with the right kind of fertilizer throughout the growing season.
WHAT TOMATOES NEED:
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Nitrogen (N): for leafy growth
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Phosphorus (P): for root development and flower/fruit production
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Potassium (K): for overall plant health and resistance to stress
FERTILIZING TIPS:
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Use an organic slow-release fertilizer at planting time to feed over several weeks
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Once flowering begins, switch to a liquid fertilizer every 2-4 weeks to support fruiting
PRO TIP: Avoid high-nitrogen fertilizers once your plants start setting fruit, too much nitrogen = too many leaves and not enough tomatoes!
8. IGNORING PEST AND DISEASE PROBLEMS
It can be tempting to look the other way when you notice a few holes in your tomato leaves or a little bit of yellowing. But with tomato plants, a small problem can escalate quickly if you don’t act early.
Tomatoes are magnets for pests like aphids, tomato hornworms, leaf footed bugs, and spider mites, not to mention fungal diseases like early blight and powdery mildew. Waiting too long to take action can result in stressed plants and ruined fruit.
COMMON TOMATO PEST AND DISEASE SIGNS TO WATCH FOR:
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Chewed leaves or missing chunks – likely hornworms or caterpillars
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Sticky residue or curled leaves – often a sign of aphids on back of leaves
- Whitish spots or blemishes on tomato fruit – most likely leaf footed bugs
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Spots on lower leaves – could be early blight or fungal infection
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White powder on leaves – usually powdery mildew
BEST PRACTICES TO PREVENT ISSUES:
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Inspect your plants daily, especially the undersides of leaves
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Remove affected leaves and pests by hand as soon as you spot them
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Use Arber, neem oil, insecticidal soap, or BT spray as organic control options
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Rotate crops each year to avoid recurring soil-borne diseases
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Space your plants properly and prune lower leaves to increase airflow and reduce humidity around the plant
PRO TIP: Companion planting with flowers like marigolds and herbs like basil can naturally deter some pests and attract beneficial insects like ladybugs and parasitic wasps.
9. LETTING TOMATO SUCKERS TAKE OVER (Without a Plan)
If you’ve ever looked closely at a tomato plant and noticed little shoots growing out of the spot where a leaf meets the main stem, you’ve seen a sucker. These little guys seem harmless at first, but left unchecked, they can quickly turn your tidy tomato plant into a tangled jungle.
Now, pruning isn’t absolutely necessary, but not having a pruning strategy can lead to problems, especially with indeterminate (vining) varieties.
WHAT HAPPENS IF YOU DON’T MANAGE TOMATO SUCKERS:
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Plants become overly leafy and crowded
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Airflow is reduced, creating the perfect environment for disease
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The plant puts energy into growing more stems and leaves instead of fruit
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It becomes harder to spot pests or ripening tomatoes
- Learn more about if you should prune your tomato plants here
TO PRUNE OR NOT TO PRUNE?
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Determinate tomatoes: These grow to a set size and produce fruit all at once. Minimal pruning is best here, removing too many suckers can reduce your harvest. Just remove any suckers below the first flower cluster to keep things tidy.
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Indeterminate tomatoes: These grow and produce all season long and benefit from regular pruning. Removing suckers helps direct energy into fruit production and improves airflow.
TOMATO PRUNING TIPS:
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Use clean, sharp pruners or pinch suckers with your fingers when they’re small
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Prune in the morning when plants are less stressed
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Don’t remove all the foliage, tomato leaves are important for photosynthesis and shading the fruit
PRO TIP: If you’re growing in a small space or using a trellis, pruning is essential to keep the plant manageable and productive.
10. PLANTING TOMATOES TOO CLOSE TOGETHER
It’s easy to underestimate how big tomato plants can get. When you’re starting with those small seedlings, it’s tempting to squeeze in just one more, but crowding your tomatoes is a recipe for trouble.
Tomato plants need space to breathe, stretch, and grow strong. Without enough room between them, you’ll end up with poor airflow, tangled vines, and an open invitation for pests and diseases.
WHAT HAPPENS WHEN TOMATOES ARE OVERCROWDED:
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Limited airflow leads to fungal diseases like early blight and powdery mildew
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Increased competition for sunlight, nutrients, and water
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Harder to prune, water, and harvest without damaging the plant
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Less fruit and more foliage as plants struggle to reach for light
RECOMMENDED TOMATO PLANT SPACING:
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Indeterminate tomatoes (vining types): 24–36 inches apart (can plant closer together, 12 inches apart, if you keep to a single stem and prune heavily)
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Determinate tomatoes (bush types): 18–24 inches apart
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In containers, give each plant its own pot that’s at least 5 gallons in size
PRO TIP: Always think about the mature size of your tomato plant, not the size it is on planting day. Giving your tomatoes proper breathing room sets the stage for healthier growth and a more abundant harvest.
Growing tomatoes can be one of the most rewarding parts of your garden, but they can also be one of the most finicky plants if you’re not careful. By avoiding these common mistakes, you’ll set yourself up for healthier plants, fewer problems, and a whole lot more juicy, sun-ripened tomatoes to enjoy.
Remember, gardening is always a learning process. Even seasoned growers still run into the occasional hiccup! So take notes, adjust as you go, and most importantly, have fun watching those tomatoes grow.
