How to Plant Tomatoes: The Right Way, Start to Finish

Get planting day right and your tomatoes are halfway to a great harvest before they’ve grown an inch. Get it wrong, plant too early, too shallow, too crowded, and you fight problems all summer. Problems you baked in on day one.

The good news is that planting a tomato is simple once you know the handful of things that actually matter. Timing, depth, and spacing. Nail those three and the plant does the rest. This guide walks you through all of it, from picking the right week to firming the soil around a freshly planted seedling. Plus the one trick that turns a spindly transplant into a powerhouse.

When to plant tomatoes

This is the question everyone asks, and the answer isn’t a date on the calendar. It’s a condition. Tomatoes are warm weather plants that hate the cold, so you wait for two things to line up.

First, all danger of frost has to be past. A single late frost can kill a young tomato overnight, so this one is non negotiable. Second, the soil has to warm up. Utah State University Extension says to plant once soils are warmer than 60 degrees. Warmer is better, and if you can wait until the soil hits 65 or 70, the plants take off faster.

There’s a third thing worth watching, and it’s the one people miss: night temperatures. Once nights are steadily above 50 degrees, you’re golden. Let them dip below 50 and a tomato just sulks, and its flowers may not set fruit at all. So a warm afternoon means nothing if the nights are still cold. Our guide to how cold tomatoes can tolerate puts exact numbers on every stage.

Put simply, don’t rush it. A tomato planted into cold April soil shivers through chilly nights. One planted two weeks later into warm ground overtakes it. Patience wins here. If you want the exact window for your area, our guide to when to plant tomatoes by zone breaks it down by frost date and region.

Harden off before you plant

Here’s a step that trips up beginners every year. You can’t take a tomato that’s been coddled indoors or in a greenhouse and drop it straight into the open garden. The sun, wind, and temperature swings will shock it. It may take weeks to recover, if it recovers at all.

So you harden it off first. That just means introducing the plant to the outdoors slowly over about a week to ten days. Start with an hour or two in a sheltered, shady spot. Then add a little more time, sun, and wind each day. By the end, the plant is spending full days outside and is tough enough to handle its new home. Skip this and you undo a lot of the work you’re about to do. If you started your own from seed, our seed starting guide covers hardening off in more detail.

Plant them deep (the trick that matters most)

If you take one thing from this whole guide, make it this. Tomatoes should be planted deep. Much deeper than they were sitting in their pot.

Here’s why it works. Tomatoes have a special trick most plants don’t: they grow roots along any part of the stem that’s buried in soil. Those little bumps you see on a tomato stem are roots waiting to happen. So when you bury two thirds of the stem, all of that buried section turns into roots. You end up with a huge, deep root system instead of a shallow one. A bigger root system means a stronger plant, better able to find water and food and shrug off a hot spell.

To do it, strip off the lower leaves so you’ve got a bare stem. Then set the plant deep enough that only the top few sets of leaves show above the soil. Don’t worry about burying that much stem. It’s exactly what you want.

Got a tall, leggy transplant that stretched too much indoors? Even better, because there’s a clever fix. Instead of digging a deep hole, dig a shallow trench and lay the plant down sideways in it. Gently bend the top up out of the soil, then bury the whole stem. University of Minnesota Extension describes exactly this. Dig a trench three to four inches deep, strip the lower leaves, lay the plant down, and bury the stem up to just below the remaining leaves. The buried stem roots all along its length, and that weak, floppy seedling becomes your best plant of the season.

How to plant a tomato, step by step

First, the spot: tomatoes want 6 to 8 hours of direct sun, and no planting technique makes up for shade. If you’re unsure your spot qualifies, check how much sun tomatoes need before you dig.

Once you’ve got timing and depth sorted, the actual planting takes about two minutes a plant.

Start by digging a hole deep enough to bury most of the stem, going by the depth we just covered. If your soil is poor, mix a couple of handfuls of compost into the hole. This is also the moment to add a slow release or starter fertilizer if you’re using one. Our fertilizing guide covers what to feed and when.

Pop the plant out of its pot. If the roots are circling in a tight ball, tease them apart gently so they’ll spread out into the soil. Set it in the hole at the right depth, then backfill with soil and firm it down around the stem with your hands. You want good contact between roots and soil, no big air pockets.

Then water it in, and water it well. A deep drink right after planting settles the soil around the roots and gives the plant the moisture it needs to recover from the move. This first watering matters more than people think, so don’t skimp on it.

One more tip from the pros. Plant on a cool, cloudy day, or in the late afternoon, rather than in the blazing midday sun. Minnesota’s extension recommends exactly this. A gentler moment gives the plant time to settle before it faces full heat, which cuts down on transplant shock. Planting into a brutal southern summer is its own game, covered in growing tomatoes in extreme heat.

How far apart to space tomatoes

Crowding tomatoes is one of the most common mistakes, and it’s an easy one to make when the plants are small. Those little seedlings look lonely two or three feet apart in May. By July they’ve grown into a jungle. Plants packed too close fight for light, trap damp air that breeds disease, and generally underperform.

How far apart depends on the type of tomato and how you’re supporting it. Here’s the breakdown, drawn from Iowa State University Extension:

The pattern is easy to remember. The more you rein a plant in with a stake, the closer you can space it. The more you let it sprawl, the more room it needs. When you’re unsure, err on the side of more space. Good airflow between plants is one of your best defenses against the fungal diseases that plague tomatoes. A little extra elbow room pays off all season. Not sure whether your variety is determinate or indeterminate? Our types of tomatoes guide sorts it out.

Planting in raised beds and containers

Raised beds are a favorite for tomatoes, and for good reason. The soil warms up faster in spring, drains better, and you fill them with exactly the rich soil tomatoes love. Everything above still applies: plant deep, water in well. But you can nudge the spacing a touch tighter than open ground, since the soil is richer and you’re likely staking. Even so, don’t cram them. Two feet between plants is a sensible minimum in a bed.

Growing in pots is a different setup with its own rules, mostly around pot size and watering. If that’s your plan, head to our full guide on growing tomatoes in pots. Check what size pot tomatoes need before you plant, because too small a pot is the number one container mistake.

What about transplanting seedlings you started yourself?

If you grew your own tomatoes from seed, there’s a middle step between the seed tray and the garden. Moving those seedlings up as they grow, and eventually shifting them to their final home. That whole process, potting up, handling transplant shock, and getting the timing right, has its own guide. See transplanting tomato seedlings for the details, then come back here for planting them out.

Common planting mistakes to avoid

Most planting day problems come down to a short list. Dodge these and you’re ahead of most gardeners.

Planting too early is the big one. A warm week in spring is tempting, but cold soil and cold nights stall a tomato and can kill it. Wait for warm ground and nights above 50.

Planting too shallow wastes the tomato’s best trick. If you leave the plant sitting at the same depth it was in the pot, you miss out on all those stem roots. Bury it deep.

Crowding comes next. Those roomy gaps in spring are correct, even though they look silly. Give the plants the space on the chart and thank yourself in July.

Skipping the hardening off shocks a soft indoor plant into a rough start. Ease it outside over a week first.

And forgetting to water in leaves fresh roots sitting in dry pockets of soil. Always give a deep soak right after planting.

Frequently asked questions

How deep should I plant tomatoes?

Deep. Bury about two thirds of the stem, stripping off the lower leaves first, so only the top few sets of leaves show above the soil. The buried stem grows roots along its length and builds a much stronger plant.

How far apart should tomato plants be?

It depends on type and support. Staked indeterminate plants go 18 to 24 inches apart, caged ones 30 to 36 inches. Bush determinate types sit about 24 to 30 inches apart, with rows roughly 3 to 4 feet apart. More space means better airflow and less disease.

When is it safe to plant tomatoes outside?

Once all danger of frost has passed, the soil is above 60 degrees, and nights stay above 50 degrees. A warm afternoon isn’t enough on its own, so watch those night temperatures before you plant.

Can I plant a leggy tomato seedling?

Yes, and there’s a great fix. Dig a shallow trench, lay the plant on its side, and bury the long stem, bending just the top up out of the soil. The buried stem roots all along its length and the plant catches up fast.

Should I put anything in the hole when planting tomatoes?

A couple of handfuls of compost helps, and a slow release or starter fertilizer is fine if your soil is poor. You don’t need much. Skip the old eggshell and epsom salt tricks, since they don’t do what people claim.

Bottom line: wait for warm soil and warm nights, and harden the plants off first. Then plant them deep, water them in well, and give them room to breathe. Get those basics right on planting day and the season gets a whole lot easier. From here, our complete guide to how to grow tomatoes takes you through watering, feeding, and everything else that follows.

Sources: Utah State University Extension: Tomatoes in the Garden · University of Minnesota Extension: Growing Tomatoes · Iowa State University Extension: Tomato Spacing