Growing Tomatoes Organically: 11 Tips For Thriving Plants
If you think organic growing equals smaller harvests and less healthy crops, think again. Farmer Briana Yablonski shares how to grow tomatoes organically so you can avoid harmful pesticides and herbicides and enjoy bountiful harvests of flavorful fruits.
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Tomatoes are some of my favorite plants to grow in my summer garden. Snacking on juicy cherry tomatoes straight from the plant and harvesting Roma tomatoes for sauce make long days in the garden feel particularly rewarding. And when you choose to grow tomatoes organically, you don’t have to worry about consuming pesticides or fungicides.
I’ve grown tomatoes for the last ten years in locations including large farms and small gardens. All of these plants were grown using organic methods, and I’ve learned a few helpful growing tricks in the process.
In this article, I’ll share some tips to help you grow tomatoes organically so you can enjoy a healthy environment and a rewarding harvest.
Choose Your Variety Carefully
If you plan to grow organically, that means you’ll avoid synthetic fertilizers, pesticides, and fungicides. You can certainly grow healthy tomato plants without these products—trust me, I’ve done so over the past ten years. However, you’ll need to take a preventative approach to keep problems at bay.
This starts with choosing the right tomato varieties. While it’s possible to grow any type of tomato organically, it’s often helpful to start with a disease-resistant variety. These cultivars are known to grow through pressure from diseases like early blight, fusarium wilt, leaf mold, and tomato mosaic virus. Resistant doesn’t mean the plants are immune to these diseases, but it does mean they are less likely to become infected.
It’s also helpful to choose organic seeds. These seeds were collected from plants that were grown using organic methods. That means the plants survived diseases and pests without any synthetic treatment methods. Therefore, the seeds will produce plants that are well-suited to grow well in organic environments.
Start With Healthy Plants
Regardless of which tomato variety you choose to grow, you must start with healthy transplants. It doesn’t matter if you purchase seedlings from a nursery or start tomato seeds at home.
What’s important is that the plants are green, free from pests, and in a properly-sized container. Look for strong, fat stems that can stand up to outdoor conditions. Avoid any plants with discolored foliage, tight roots, or pests like aphids and whiteflies.
I like to steer clear of seedlings with flowers, since this means the plants have put energy into producing flowers rather than growing strong leaves and roots. However, flowers aren’t a deal breaker, since you can remove them before planting.
Plant in Full Sun
Regardless of whether or not you chose to grow tomatoes organically, you must plant them in full sun. This light provides the plants with the energy they need to grow vigorously and produce fruits and flowers. Planting in partial shade will drastically reduce the plant’s size and number of fruit.
Sun also helps dry the leaves and prevent diseases from taking hold. Therefore, you should always choose morning sun and a few hours of afternoon shade instead of morning shade.
Choose Well-Draining Soil
Tomatoes don’t like wet feet, so avoid ground that stays soggy after a heavy rain. If you notice water is slow to drain in the area you hope to plant your tomatoes, spend a few minutes aerating the soil before planting.
A digging fork or broadfork are both suitable tools for this task. Just insert the tines fully into the ground, gently pull back on the handle until the soil cracks, then repeat this process every foot. Mixing in well-aged compost in your planting area will also help improve drainage.
If you’re worried about heavy clay, rocky ground, or compacted soil, you can always choose to use raised beds filled with a high-quality soil mix. Just make sure the tomatoes’ large roots have at least two feet of soil to expand.
Keep the Foliage off the Ground
Many tomato diseases are soilborne, which means they originate from the ground. Verticillium wilt, fusarium wilt, and corky root rot are a few soilborne pathogens.
Keeping your tomato plants’ leaves off the ground will help prevent these diseases from attacking your plants. Trellising helps keep the majority of the plant off the ground while providing improved airflow. However, even if you trellis your plants, the lower leaves may still touch the soil.
I always like to prune the lower leaves from my tomato plants before I plant them in the ground. However, it’s important to leave at least two true leaves so the plant can continue to photosynthesize and grow. You can always remove these leaves a week later when the plant has grown.
Mulch the Base of the Plants
Mulching the soil around your tomato plants is one of the best things you can do when you grow tomatoes organically. It helps retain moisture, prevents the soil from splashing onto your plants, and suppresses weeds. Organic mulches like straw and wood chips also break down over time and enrich the soil with organic matter.
I recommend mulching your plants right after you plant them. You can use many different types of mulch, including leaf mulch, wood chips, and straw. If you don’t want to deal with spreading these materials, you can lay landscape fabric on your bed and plant the tomatoes into it. Burning holes into the plastic mulch is neater than cutting, since the heat prevents frayed plastic edges.
Provide Plenty of Fertility
When you grow tomatoes organically, you can’t rely on inputs of quick-release synthetic nitrogen and phosphorus. And that’s okay! However, it does mean you have to plan ahead and pay attention to soil health.
Some people think that applying lots of nitrogen is all that tomatoes need to grow into healthy green plants. And while nitrogen will encourage vegetative growth, too much of it will lead to bushy green plants with few flowers and fruits. Therefore, you should apply a fertilizer that contains at least as much potassium and phosphorus as it does nitrogen.
Fortunately, you can find organic fertilizers designed specifically for tomatoes. These products contain materials like feather meal and bone meal that slowly release nutrients to the plants. Applying these products at planting and every month throughout the growing season will provide your tomato plants with a steady stream of nutrients.
Since organic nutrients need to be broken down by bacteria before they can become available to plants, you should also foster healthy soil life. Adding compost can help boost your soil with beneficial microbes, and adding organic matter will help feed these good microorganisms.
Water Regularly
Tomatoes require lots of water, especially when they’re working to develop their juicy fruits. However, how you water is just as important as how much you water.
Young plants require frequent irrigation as their small root systems settle into their new home. Watering every few days will limit symptoms of transplant shock and help the plants deal with any stress they’re facing.
As the plants grow older, you don’t have to water them as often. Instead, aim for deep waterings to encourage the plants to develop deep and strong root systems that can withstand drought. However, don’t let the soil alternate between bone dry and soaking wet, since this sudden swing in soil moisture can lead to cracked fruits and problems with nutrient uptake. Watering deeply one to three times a week is generally sufficient.
Drip irrigation keeps the foliage dry, so it’s better than overhead sprinklers or hoses. Plus, it sends the water directly to the ground, so little is lost to evaporation. If you don’t have a drip irrigation system, you can still use a watering can or hose. Just water near the base of the plant to keep the leaves dry.
Trellis Your Plants
Staking your tomatoes keeps the plants tidy and makes them easier to harvest. However, supporting your plants also helps keep them healthy. Keeping the plants off the ground improves airflow, reduces disease, and makes it easier to prune your plants. All of which makes it easier to grow tomatoes organically!
You can trellis tomato plants in multiple ways. A simple wire tomato cage works well if you’re only growing a few plants and want a simple solution. However, indeterminate plants will quickly grow over the tops of these cages.
Another option is to insert a wire cattle panel next to your plants and attach the plant to the panel as it grows. You can tie the plant to the panel using twine or purchase plastic clips that allow you to easily connect the growing stems.
If you’re growing a row of tomatoes, you can use t-posts and twine to support your tomatoes. Insert metal t-posts into the ground every three to four plants so they’re in line with the row of plants. Next, tie a piece of twine to an end post, run it along the outer edge of your plants, wrap it around the next t-post, and repeat until you reach the end of the row. Complete the process on the other side of the plants so they’re boxed in between the two pieces of twine, and add new strings every 8-12 inches.
Prune to Increase Airflow
Dense foliage may make your tomato plants look lush and full, but all those leaves can limit airflow and increase the chance of disease. When air can’t move freely through the plant, moisture lingers on the leaves and stems. This creates the perfect environment for fungal and bacterial diseases to take hold—something you definitely want to avoid when growing organically.
Pruning your tomato plants helps keep them healthy by improving airflow and reducing excess humidity around the leaves. You don’t need to strip your plant bare, but removing suckers—the shoots that grow between the main stem and branches—can make a big difference. You should definitely prune Indeterminate varieties, but determinate varieties don’t require pruning outside of removing lower leaves.
In addition to removing suckers, I recommend cutting away any discolored or spotted foliage. Not only does this limit the spread of disease, but it also directs the plant’s energy toward producing healthy leaves and fruit rather than maintaining unhealthy leaves. Always use a clean pair of pruners or a knife, and sanitize your tools between plants to prevent spreading disease.
Start pruning once your tomato plants are about a foot tall, and continue the process throughout the season. Just remember not to remove too many leaves at once—your plants still need plenty of foliage to photosynthesize and fuel fruit development.
Harvest Early
When you grow tomatoes organically, you’ll want to protect your hard-earned fruit from sunscald, cracking, and critters. One easy way to do this is to harvest your tomatoes before they’re fully ripe. While you may think vine-ripened tomatoes are best, research has proved this theory wrong.
Tomatoes picked at the “breaker” stage—when the fruit just begins to blush with color—will continue to ripen off the vine. Although you may think these fruits won’t taste as good as their vine-ripened counterparts, research shows that there’s no difference in quality.
Another perk of harvesting early is that you reduce the weight burden on your plants. Large, ripening fruits can sometimes cause branches to droop or break, especially if the plants are loaded with big tomatoes or not well supported.
