Growing Tomatoes for Beginners

Tomatoes are the most popular vegetable (well, fruit) grown in home gardens. They’re delicious, money-saving, good for fresh-eating and preserving, and come in endless colors, shapes and sizes. Learn how and when to select tomato seedlings, step-by-step instructions for planting tomato plants in the ground and basic care tips for watering, fertilizing, pruning and keeping your tomato plants healthy until harvest. Mastering tomatoes is a skill learned over time, but any beginner can succeed with tomatoes by learning the basics.

Should you Start Tomatoes from Seeds or Seedlings?

Growing Tomatoes from Seedlings

When you start tomatoes from seedlings, someone else does the work of starting the seeds and caring for the seedlings for the first few weeks. It’s significantly less time-consuming and you don’t need seed starting supplies or a dedicated space in your home. The downside is that big box stores and garden centers generally carry a very limited number of tomato seedling varieties. However, you may be able to find a wider variety of heirloom tomato seedlings at farmers markets and small local farms.

If it’s your very first year growing tomatoes, especially if you only plan to grow a few tomato plants, I recommend starting with seedlings and focusing on learning how to plant and care for those rather than taking on the additional tasks of setting up an indoor seed starting space, learning how to start seeds and caring for indoor seedlings.

Growing Tomatoes from Seed

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Starting tomatoes from seed requires more work, time and resources but, depending on your situation, it might be worth going for it even if it is your first year gardening. You might choose to start from seed if:

Growing specific or unusual varieties of tomatoes is important to you.
You know for sure you eventually want a large garden grown from seed and you want to start learning how to grow from seed as soon as possible.
Your desire to garden is motivated more by sustainability and self-sufficiency.
You’ve already grown a few easy vegetables or flowers from seed, have some of the supplies already, and want to do more.
You want to grow a lot of tomatoes and/or other vegetables and buying everything from seedlings is cost prohibitive.

Planting Tomatoes for Beginners

Best Time to Plant Tomatoes

Wait to purchase and plant your tomato transplants until after all risk of frost has passed AND nighttime air temperatures are reliably above at least 10C, ideally 15C. In my 5b garden this can be as late as mid-June. It’s counterintuitive but you don’t gain anything from planting tomatoes before conditions are ideal. They will just sit there and languish. Tomatoes planted later tend to catch up and eventually do better than tomatoes planted too early.

At the same time, you want to plant your tomatoes with enough time left in your growing season for the tomatoes to ripen. This is especially important if you live in a cool, short growing season. Check the “days to maturity” of the variety you are planting. This number usually refers to the number of days from transplant to harvest, so count from your transplant day to the first expected frost in fall, to be sure there are enough days in your growing season. If you’ve got a short season, choosing varieties that ripen quickly, about 55-60 days, may be your best bet.

Buying and Selecting Seedlings

Make sure you know what types of tomato seedlings you want to grow. See my post on choosing tomato types and varieties if you need help deciding.

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When selecting your seedlings, look for:

Short and stocky seedlings that aren’t leggy or wilted.
Dark green leaves that are free from yellow or black spots.
Seedlings without blooms. (Cut any blooms off before transplanting).
Healthy root systems that have not begun to swirl around the pot.

Don’t assume transplants you purchase have been hardened off properly – especially if you’re purchasing from a big box store or somewhere that doesn’t specialize in plants. Harden seedlings off before transplanting.

Where to Plant Tomatoes

Tomatoes require rich, well drained soil in a full sun location, which means at least 6 hours of direct sun per day, and ideally more. This is especially important in colder northern climates (zone 5 and below) with shorter growing seasons.

If growing tomatoes in warmer southern climates (zone 7 and up) they may benefit from some partial shade or shade protection from the hot afternoon sun. Tomatoes like warm, but not very hot, temperatures, and will often drop their blossoms and fail to set fruit when temperatures rise above 30C (86F).

How to Plant Tomatoes in the Ground

Make sure your seedlings are properly hardened off, the nighttime soil temperature is at least 10C (50F), and there are no frosts in the weather forecast. If necessary, wait another week or so if conditions are not favorable.
Transplant your seedlings either on a cloudy day or in the evening to give them some time to adjust before the afternoon sun hits them.
Plan the spacing of your tomatoes. In general, you’ll need between 18” and 36” between each plant, but the exact spacing depends on the type of tomato plants you are growing and how you plant to stake or prune them.
Prepare your tomato holes. Unlike most vegetables, tomatoes do well when planted deeply. Roots will emerge anywhere along the stem, and the plants will develop healthier root systems. Dig deep holes and add fertilizer or amendments to each hole, if desired. I like to add a handful of compost, a tablespoon or so of bone meal and a small handful of granular slow-release fertilizer to the bottom of each hole and top dress or mulch the beds with a layer of compost. You could also add some crushed eggshells, Epsom salts, or worm castings, if you like. Mix any amendments into the soil in the bottom of the holes so the roots won’t sit directly on fertilizer. If your tomatoes are very tall and leggy, you might try trench planting them horizontally.
Using a pair of sharp, clean pruners, remove the leaves from the bottom ½ to ⅔ of the tomato seedling. Transfer the seedling into a prepared hole to a depth just underneath the bottom remaining set of leaves and fill the hole back in with soil.
Water the newly planted seedlings well. Direct the water towards the roots of the tomato plant to keep the leaves as dry as possible.
Mulch around your tomato plants using the mulch of your choice. Straw is a common mulch, but in my wet and humid climate I prefer to use a layer of compost, which doesn’t house slugs and snails the way straw does. Mulch protects the tomato foliage from microbes in the soil that splash up in the rain or when you water and cause disease.
Set up your support system. Unless you are planting dwarf or small determinate tomatoes, you will need some sort of support or staking. From simple cages and singular stakes to more elaborate support systems, there are lots of options to choose from. But however you decide to support your tomatoes, aim to set up your supports at or near planting time (or even before). If you wait too long you may damage your plant’s roots or have difficulty attaching large unwieldy plants to your supports.

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Basic Tips for Tomato Plant Care

Tomatoes are a long-season crop, so the key to success growing them is regular monitoring, care and maintenance. You will need to keep your tomatoes consistently watered, fertilized, pruned or trained up supports, if necessary, and monitored for disease and pests. There is a lot to learn about each of these tasks, but a few basic tips are all you need to get started.

Watering Tomatoes

Like most vegetables, tomatoes need about 1 inch of water per week, sometimes 2 inches during the hottest weeks of summer.
Early in the morning is the best time to water your tomatoes.
Aim to water deeply 1-2 times per week, rather than a little bit every day and aim for consistent moisture, don’t let the soil dry out completely.
Aim to keep the foliage as dry as possible as you water. Water the soil around the plants, rather than pouring the water over the top of the plant.
Tomatoes in containers will require more frequent watering, once a day for most of the season and twice a day on the hottest days of summer.

Fertilizing Tomatoes

Tomatoes are heavy feeders but there is more than one way to keep them fed. The best way to fertilize your vegetables is to respond to the signals you receive from your plants. For instance, when tomatoes want to be fed, their foliage will turn a pale yellow-green and their growth will slow.

For beginners new to fertilizing tomatoes, I suggest:

Amend your tomato beds at the beginning of the growing season with a layer of compost and some granular slow-release fertilizer.
Add some compost (and possibly other amendments) to your tomato planting holes.
Feed your tomato plants about every 2 weeks with some sort of relatively-balanced water-soluble fertilizer that is, ideally, slightly higher in phosphorus and potassium (the “P” and “K” on the fertilizer packaging) than nitrogen (the N).

Pruning & Training Tomatoes

Pruning is only necessary if you are growing indeterminate tomatoes. Determinate or bush type tomatoes should not be pruned. If you don’t prune your indeterminate tomatoes they can quickly become a tangled mess, overtake your supports and become more susceptible to disease. I suggest checking on your tomato plants at least once a week to prune and tie your tomatoes up their supports.

For air circulation, keep the bottoms of your tomato plants pruned up and clear of foliage and fruit. I find fruit at the bottom of the plants tends to droop to the ground and rarely makes it to a ripe stage without insect damage.
Prune out most of the suckers. It depends on how you stake your tomatoes and how close together they are but, unless you are letting your tomato plants sprawl along the ground, each plant should have no more than 1-3 main stems. Prune out the rest.
“Top” your tomato plants by cutting off the main growing stem at the very top about 6-4 weeks before your last expected frost. This will ensure that as much fruit as possible has a chance to ripen before a killing frost.

How to Avoid Tomato Diseases & Pests

The best defense against disease and pests is to get out in your garden regularly so you can stop any problems as soon as they arise. To keep your tomato plants healthy all season:

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Check regularly for bugs or eggs. Hand pick bugs and crush eggs you may find on undersides of leaves, remove and discard diseased leaves.
Try under or inter-planting your tomatoes with companion plants like basil, marigolds, mint, nasturtium that may help attract beneficial bugs or deter pests.
Keep your tomatoes well-pruned to promote good air circulation (see above).
Practice good garden hygiene – always clean your pruners between each plant and never work in your garden when the leaves are wet.
Use a thick layer of mulch to minimize soil splashing onto your plants. Try grass clippings, shredded leaves, wood chips, straw or compost – avoid dyed wood chips.

Harvesting Tomatoes

Most ripe tomatoes will gently give way when you squeeze them and should appear to be the color pictured or described on your seed packet. Dark purple blue or black varieties can be more challenging to gauge ripeness.
However, the ripeness of a tomato can depend on the variety, the weather, and your personal preference for how firm or ripe you like your tomatoes to be. Some say you should harvest tomatoes fully ripe, while others suggest harvesting just before they are fully ripe. Try harvesting your tomatoes at various stages to see what works for the varieties you are growing and your personal preference.
If harvesting tomatoes when slightly under ripe, know that tomatoes that have begun to pick up some color will continue to ripen inside on the counter. Fully green tomatoes (that aren’t meant to be eaten green) will not ripen off the vine.
The late summer garden can be overwhelming. Plan ahead to make sure none of the tomatoes you harvest go to waste. Collect tomato recipes and get your supplies ready for any canning or sauce-making projects you’d like to undertake well in advance of tomato season so everything is ready when your tomatoes are.