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Tomato Gardening 101: What’s the Best Soil for Tomatoes?

Tomato Harvest

Everyone knows that home garden tomatoes taste an order of magnitude better than ones that come from the grocery store’s shelves. They are fresher, juicier, sweeter, and just plain delicious.

Tomatoes grown for supermarkets are bred for their firmness, ability to withstand travel, long shelf life, uniformity, and even color. That also makes them bland, mealy, and not very tasty.

They’re the perfect ingredient in many meals, including in appetizers, salads, and to even making your favorite pasta sauce!

So, consider growing tomatoes on your own; there are plenty of varieties –whether garden favorites or unique heirlooms — to choose from and you can grow them until they are perfectly ripe and delicious.

Read on to learn everything you need to know for effective tomato gardening in your home garden today, including information on the best soil for tomatoes.

Essentials for Tomato Gardening

Sunshine

More than anything, tomatoes need sun. Full sun, for that matter, and no less than 8-hours per day. If your garden plot receives less than ideal amounts of sunshine (and the warmth it provides) you can still grow beautiful tomatoes but will have to improve conditions for them to thrive.

Spread black plastic around your plants. This will help the soil soak up heat and control weeds and many insects, too. Mulching will also conserve soil moisture, which can prevent tomato problems (blossom end rot, cracking) associated with uneven watering.

Tip: Some growers prefer to use red tomato mulch, which may have the added benefit of reducing the number of days to maturity and improving tomato yields.

A fence or barrier behind your plants will reflect sunlight back onto them. For best results, use something shiny or bright — a white sheet hung between two posts or an old door painted white will get the job done. If it is heat, more than sunlight that you are trying to increase, paint your fence or barrier a dark color.

Row covers, draped over tomato plants can trap heat and some moisture — creating a mini-greenhouse effect. There are many different kinds of row covers, but choose a gauzy material that will protect plants from cold and let rain through. Make sure to check often to be sure your plants are not overheating.

Do you live in an area with high temperatures? If so, you may need to cool your plants. Tomatoes drop their flowers, fail to color-up, and pretty much stop growing when temperatures consistently climb above 90°F.

To protect plants from too much heat consider shading the plants. Be careful not to just drape something over them, as this will create more heat. Shade the side of the plants being hit with the sun and make sure there is plenty of air circulation.

Soil

Tomatoes thrive in soil rich in minerals and micronutrients including phosphorus, potassium, calcium, and magnesium.

As with most garden vegetables, they do well in well-drained, fertile, sandy loam with a soil pH of 5.8 to 7.0. Fortunately, tomato plants do well in almost all types of soil except heavy clay soil.

Mix several inches of organic matter, compost, or aged animal manure into the upper 4-8 inches of soil before planting.

If a soil testing kit shows the pH level is above 6.0, apply elemental sulfur — if it is below 6.0, add dolomite lime to balance it.

There are certain horticultural compounds that you can for the best soil for growing tomatoes:

Perlite: Perlite is a byproduct of volcanic glass that helps keep the soil fluffy and prevents it from getting too hard and compact.

Sand: To promote drainage, horticultural sand can be added to the mix. It can also give the soil more structural strength, allowing tall tomato plants’ roots to anchor and prevent them from tipping over.

Sphagnum peat moss: Most potting soils and seed starting media contain this ingredient. It can hold several times its weight in moisture and release it as needed to the plant’s roots. It also retains nutrients, preventing them from being washed out of the soil when the plant is watered.

Alfalfa meal: Alfalfa adds essential nutrients to the soil, including vitamin A, nitrogen, phosphorus, and potassium. It is typically sold in pellet form, which can be easily mixed into organic potting soil for container plants or raised beds.

Read till the end of this article for our recommendations of some of the best soil for growing tomatoes on the market!

Space

How much space you’ll need per plant depends on the tomato variety you are growing and whether or not your plants are staked or caged. Proper spacing will assure that your plants receive plenty of sunlight and good air circulation, which will prevent many plant diseases from developing.

When it’s time to plant, refer to the seed packet or seedling directions for specific spacing requirements. Some general guidelines are:

  • Space staked tomatoes and indeterminates 1.5 to 3-feet apart
  • Determinates grow more compact and can be spaced 2-feet apart
  • Plant unstaked/uncaged plants 6-feet apart
  • Tomatoes with a 2-foot diameter cage can be planted 4-feet apart
  • Allow at least 3-feet between rows of tomatoes

Where to Plant Tomatoes

Traditionally, it has been recommended that plants in the same family (in this case the Solanaceae Family) should not be planted near each other or in the same ground as the previous year.

For tomatoes, this would include eggplants, peppers, and potatoes, in addition to other varieties of tomatoes.

While members of the same plant family often share common pest problems, it is nearly impossible to keep them apart if you have a small to medium sized garden.

In her book Great Garden Companions: A Companion-Planting System for a Beautiful, Chemical-Free Vegetable Garden, Sally Jean Cunningham suggests planting tomatoes, eggplants, and pepper together and mulching them with black plastic.

Feed all of them with high-phosphorus bat guano which will promote flowering and fruiting. However, it’s important to note that potatoes have different nutritional needs, so plant them separately.

Garden plants that seem to grow well near tomatoes — and visa versa — include carrots, garlic, beans, peas, other legumes, and basil.

What Type of Tomatoes Should I Grow?

There are so many types of tomatoes to choose from that it can be difficult to decide which ones to grow. Experts suggest starting with three varieties and taking careful notes so you’ll know which ones you want to plant the following year.

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When choosing plants, ask yourself the following questions:

  • What shape, size, and use do I prefer?
  • Is this plant resistant to local diseases?
  • Which plant grows best in my climate?
  • How many plants do I want to grow?

Getting Started with Tomato Gardening

Visit your local nursery (avoid the big box stores at this point — you want to find someone who really knows what they are talking about) or jump online and visit a garden forum for answers to your questions.

Find out which tomatoes grow best in your area and get answers to any other questions you might have. Then buy a few.

Here is a little vocabulary lesson, so you won’t feel lost when the nursery salesperson starts talking about:

Determinate Tomatoes: These plants set all their fruit at once and then they are done. Blossoms grow at the end of their shoots. Usually, they do not require much pruning or staking (unless they are “vigorous” and have such big fruit that they need a little extra support). Determinate types like hot and relatively dry conditions, and will grow well in the Southwest.

Indeterminate Tomatoes: These plants grow and fruit throughout the summer. Their flowers bloom along the vines — not at the ends. Support and pruning are usually requirements of indeterminate varieties, which do well in warmer, more humid parts of the country.

Heirloom Tomatoes: These “old fashioned,” non-hybrid varieties were developed over generations by continually breeding plants with the most desirable characteristics with other plants that also had these characteristics. Plants of each generation that did not meet the grower’s requirements were pulled out and not bred again. An important point with heirloom tomato seeds is that they are usually (but not always) indeterminate and are developed in an open pollinated environment.

An heirloom plant’s defining qualities are in its dominant genes, so even if cross-pollinated with varieties are nearby, heirloom seeds will stay true, at least for a while. Eventually, you will see changes in the seeds, but by keeping them relatively separated, they will breed true (see our article Heirloom & Organic Seed: A Growing Movement).

Hybrid Tomatoes: These plants are produced anew every year and are the result of two different tomatoes being force-pollinated or “crossed” with no attempt to create a self-propagating seed. Hybrid seed will produce a plant with the characteristics that it was bred for only once.

Selecting Tomato Seedlings

If you live in an area with a short growing season, purchasing seedlings may be the best way to go, since they take less time to reach maturity and develop, well tomatoes! When it comes time to select your young seedlings look for leafy, vigorous plants. Leggy or spindly plants will likely fall over and not fare well in the garden. Stocky seedlings, about 6-8 inches tall with one main stem are best. Also, watch for plants with discolored leaves or insects on them, and do NOT choose plants that are in flower — overall yield will likely be poor.

Growing Tomatoes from Seed

Many tomato varieties and most heirlooms are only available as seed. Therefore, if you want to grow an assortment of tomato plants, chances are you’ll have to start from seed. Fortunately, starting tomatoes from seed is pretty darn easy.

When to Plant Tomatoes

Seed packets tell you to start planting 6-8 weeks before the last frost — indoors. However, if you live in a warm climate and don’t have a frost, sow the seeds 6-8 weeks before daytime temperatures reach the high 70s and nighttime temperatures don’t get below 55°F.

How to Start Tomato Seeds Indoors

Growing Media

A good organic potting soil will be lightweight and drain well. It will also be weed and pest free — typical garden soil is not! Choose an organic potting soil and your seedlings will thank you.

Containers

Just about anything works as a container to start seeds in. Egg cartons, the bottom half of milk or juice cartons, yogurt containers, etc. Just be sure to poke a drainage hole in the bottom. Of course, plastic flats purchased at the garden store work great, too. Whatever you choose, be sure to put a tray under your containers to catch the water that drains out.

Tip: Planet Natural offers a wide selection of Seed Starting Supplies to help you get your tomato plants off to a great start!

Seeds

You can’t grow seedlings without seeds, no matter how great your potting mix and ingenious your containers are. Head to your local garden store or shop online for tomato seeds.

Sowing and Sprouting

Sow seeds 1/4 to 1/2 inch deep (check the seed packet for specifics) and keep the potting mix evenly moist — if seeds get wet, then dry out, they will die. Seeds should sprout in 10-14 days.

Tip: To keep seeds evenly moist, cover your containers with plastic wrap, or keep them in a plastic bag. DO NOT let it get so wet that mold develops and remove or raise the wrap once seedlings emerge.

Keeping them Healthy

After your seeds have germinated, make sure they get plenty of direct light — 12 to 16 hours a day. If your house doesn’t get enough natural sunlight, you might need to invest in an indoor grow light system (see below). If your seedlings are on a windowsill, turn them daily to ensure even growth.

Once a seedling has developed 4 leaves, it is time to transfer it to a new pot. Here’s how:

  • Put a layer of a light potting mix in the new container.
  • Gently remove the seedling from its old pot, being careful not to damage or bruise the roots or stem.
  • Set the new seedling in the pot.
  • Carefully fill with soil. Cover most of the stem, leaving only the leaves above the soil.
  • Repeat this process when plants are 8-10 inches tall, unless it is time to move them outside.

How to Move Tomato Plants Outside

When soil temperatures reach 55-60°F and the days are in the 60s, it’s time to transplant your tomatoes. However, don’t just stick them in the ground.

They’ll need to get used to cooler outdoor temperatures and a harsher environment. For best results, start your young plants out in the shade for an hour or two before bringing them back into the house.

Increase their time outdoors until they can handle living outside full time. This process will take about 7-10 days (see Setting Out, Hardening Off).

Transplanting Tomatoes

  • Choose a cloudy day, if possible, so seedlings don’t dry out.
  • Water plants with compost tea or diluted fish emulsion an hour or two before transplanting.
  • Pinch off the lower leaves.
  • Mix 1c kelp meal, 1c bone meal, and a handful of organic compost into each planting hole.
  • Very gently, remove the seedling from its pot and place it in the planting hole.
  • Fill the hole with soil.
  • Water well.

Tomato Plant Care and Maintenance

Watering

The key to beautiful tomatoes is consistent watering. Water deeply and often, making sure to soak the soil 6 to 8 inches deep at least twice per week. Do NOT let the soil dry out between waterings, especially once tomatoes begin to develop. Uneven watering will produce misshapen fruit and a host of other problems, some of which are mentioned above. Tomatoes love water!

Tip: Keep water off the leaves of tomato plants to prevent many plant diseases from developing.

Mulching

Mulch will help retain moisture and keep your garden soil warm. Apply up to 8-inches of straw, grass, leaves, or other organic mulch soon after the soil has warmed. If you will be using tomato stakes or cages, make sure to install them prior to adding mulch. Learn more about mulches for the home vegetable garden here.

Fertilizing

Tomatoes are “heavy feeders” meaning they need a lot of nutrients.

Tomato fertilizers are often high in phosphorus, as shown by the middle number in a product’s nitrogen (N), phosphorus (P), and potassium (K) ratio. A good tomato fertilizer has a higher middle number in its NPK ratio, such as 5-7-3 or 8-15-6.

However, the ratio varies depending on whether the fertilizer is made specifically for tomatoes or for other plants as well. Some growth mixtures include natural or synthetic nutrients, while others do not.

Phosphorus will promote blossoming (and thus fruiting), whereas nitrogen will increase vegetative growth. The following applies to organic fertilizer only.

Liquid Fertilizer: Liquid fertilizers are immediately available to the plant, but they do leach out of the soil quickly, requiring frequent applications. Fertilizers such as fish emulsion or compost tea can be applied to the foliage or to the soil around the base of the plant.

Slow-Release Granules: These organic nutrients can be scattered around established plants on the surface of the soil. They release slowly, will not burn plants, contain all kinds of micronutrients in addition to nitrogen, phosphorus, and potassium, and even improve the texture of the soil as they break down.

Top and Side-Dressings: Top-dressing is adding fertilizer or soil amendments on top of the soil. Compost is an obvious choice for top-dressing. Water will leach the nutrients into the soil and earthworms will carry the compost downward.

With side-dressing, you’ll need to dig the tomato fertilizer into the soil around your plants, being careful not to disturb the root system. Side dress with a calcium source (such as gypsum) during the blossom stage to prevent blossom-end rot.

Pruning

Only indeterminate varieties of tomatoes require (or benefit from) pruning. Pruning tomatoes is the act of removing volunteer sprouts, or suckers. The suckers grow at the junction of the main plant stem and the leaf stem.

If you don’t prune your suckers, they will grow roots, leaves, and flowers just like the rest of the plant, which will actually increase the overall number of tomatoes you can harvest. However, it will decrease the size of each individual tomato since resources have to be spread throughout a bigger plant.

Tomatoes grown on a trellis or staked will need pruning, simply because the structures can’t support huge plants. Caged tomatoes are usually pruned to 4-5 producing branches. There is all sorts of advice online about pruning tomatoes.

Training and Support

Stakes, trellises, cages, fences, and anything else you can think of, can be used to train and support tomato plants. Since tomatoes are vines, they naturally grow along the ground until they find something to “grab hold of” and climb up on.

Some compact tomato varieties can be grown unsupported and will yield beautiful fruits, but they tend to take up a lot of space. Additionally, they are more apt to be attacked by soil borne insects and diseases. If growing tomatoes without support — make sure to use plenty of mulch.

Begin training plants when they are about 1-foot tall and growing quickly. Tie determinant varieties to metal or wooden poles about 5 to 6 feet tall. As plants grow, remove small sucker shoots and tie the main stem, using cloth strips or twine to the stake. Guide the plant up the stake as it grows.

Another staking option, known as the Florida weave, works well when growing many tomato plants in a row. Begin by placing several stakes between plants and weave garden twine or cord between them. Steel posts (instead of stakes) at the end of each row will provide additional support.

Cages require much less work than either staking or trellising tomatoes and are ideal for sprawling indeterminate plants. As plants grow, simply pull their branches through the cage to get the necessary support.

Tomato Plant Pests and Disease Problems

Tomatoes have all kinds of insect and disease problems associated with them (far too many to mention here). However, if your tomato plants seem unhealthy, the first thing to do is figure out what is causing the problem. Texas A&M’s Tomato Disorders page has plenty of pictures that can help you spot the problem quickly and offers a list of remedies.

How to Harvest Tomatoes

Tomatoes change color and ripen best when daytime temperatures stay around 75°F. For the best taste, leave them on the vine as long as possible. However, if temperatures drop, you’ll want to bring all mature fruits (green or not) indoors. Green tomatoes can be ripened indoors by storing them in a cool dark space, or even a brown paper bag. Within a week or two they should begin to turn red.

Another method of ripening green tomatoes is to pull the entire plant from the garden and hang it upside down in a dark area, like your basement. Believe it or not, this will work and as the fruit ripens it can be picked straight from the vine.

Tip: Never store unripened tomatoes in the refrigerator, as cold temperatures will cause them to lose flavor and turn mushy.

How to Extend Tomato Season

If you live in an area with a short growing season, and you want vine-ripened tomatoes, you’ll have to do a little pre and post season work.

Spring: Get your seeds started indoors 6 to 8 weeks before the first frost — or earlier if you plan to use a greenhouse, cold frame, or row covers. When planting time arrives, you’ll have healthy, vigorous plants that are ready to go.

Fall: When the weather turns cooler it’s time to prune away many of the leaves on your tomato plants to allow warming sunshine to reach the fruit — it’s the warmth, not the light, that will hasten the fruit’s ripening. Also, prune off all flowers that haven’t set fruit. This will divert the plant’s energy to ripen the fruits that already exist.

When a frost is expected, cover your plants with several old blankets or other materials to keep them from freezing for a couple more weeks. Remove blankets during the day to recharge the heat stored in the soil. For increased warmth, run an extension cord out to your garden and keep a light bulb (or better yet, Christmas lights) on under the cover.

Tip: To stimulate fruiting in the fall, reduce watering and/or cut the plant’s roots on three sides with a shovel.

The 3 Best Potting Soil for Growing Tomatoes in 2022

If you’re interested in growing tomatoes at home, you need the best soil to kickstart your plant’s growth properly. Here are three of the top options that we highly recommend you check out:

Best Value: Miracle-Gro Potting Soil

You can grow tasty tomatoes without spending a fortune. Miracle-Gro Potting Soil Mix provides a robust start for tomato seedlings owing to a blend of sphagnum peat moss, coconut coir, and perlite.

It also contains a wetting ingredient, which aids in the absorption of water by the dry peat moss the first time it is soaked. Once it is moistened, the mix will effortlessly absorb water.

This product, like most Miracle-Gro soil blends, contains fertilizers that give seedlings an initial spurt of growth, and the plants will not require fertilizing for a few months.

Tomatoes in containers should then be periodically fertilized, about every six weeks or as suggested on the packaging, using a high-phosphorus fertilizer formulated specifically for growing tomatoes.

Best Organic: Black Gold Potting Soil

Black Gold’s Potting Soil could be used by tomato growers who want an organic soil mix. The potting soil is all-natural, chemical-free, and produced using non-toxic procedures, as shown by its OMRI certification.

The mixture is made up of rich loam and sphagnum peat moss, as well as perlite and pumice. Pumice particles, a form of lightweight volcanic rock, aid in the drainage of the mixture while also offering structural integrity to assist anchor the roots of tall tomato plants.

Black Gold also includes compost, earthworm castings, and forest humus in addition to the base soil mix.

Best for Dry Areas: Espoma Organic Potting Soil

Espoma organic potting mix has been praised for not only nourishing your plants but also encouraging root growth for better water intake, which lowers plant stress. This is made possible by incorporating myco-tone into the potting mix.

Since the mix is excellent for moisture retention, you won’t have to water your tomatoes as frequently. Plus, the myco-tone enhancer ensures that the potting mix uses up to 30% less water than regular soils while encouraging the development of larger plant roots.

However, it’s important to note that during the cool season, you may need to reduce watering because the mix may retain too much moisture for the plant’s liking.

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