10 Tomato Transplant Tips

Cosmonaut Volkov Cosmonaut Volkov

To the Northeast vegetable garden, June brings a transformation almost as dramatic as the one of winter into spring because with the danger of frost finally behind us (we hope!) and the strong sun thoroughly warming the soil, it is time to move all seedlings outdoors and fill bare soil with plants.

Seedlings of the Solanaceous family – which include beloved tender crops such as eggplants, peppers, and tomatoes – have, along with their gardeners, been waiting for this moment since they were germinated in early spring. They can finally move from their stuffy indoor homes to summer in the great outdoors of a garden! Last week, we transplanted two tomato varieties on the farm – Cherokee Purple and Pink Ping Pong – which reminded us about the special handing tomatoes require. Tomatoes, for somewhat mysterious reasons, have been elevated to superstar fame in many home gardens. Perhaps it’s because of their irreplaceable taste and versatility as an ingredient, or perhaps it is because it can feel like a great agricultural feat to raise a tomato from seed to the first ripe, juicy fruit. Either way, tomatoes embrace their celebrity status by being finicky and picky. The coddling that they received since germination has to be weaned off slowly and very gradually as the plants mature, but is essential before, during, and for a while after transplanting.  In general, tomatoes are more susceptible than most other common vegetables to fungal diseases, such as blight. To grow healthy plants, maintaining good tomato hygiene is key – keeping them trimmed, trellised, clean of pests, etc., is essential.

 To give your tomatoes the best start in their outdoor life, follow the steps below:

1. Harden off. If your tomatoes have been living in a warm, controlled environment like a greenhouse, cold frame, or living room, they need a little time to get used to the wilder climate outside. Give them a few days to adjust to the swinging temperatures, harsh sunlight and strong wind by bringing them outside for a few hours, then increasing to half a day, a full day, and finally a day and night.

2. Find sunlight. The weather won’t always cooperate, as we all know, but we need to be ready when it does. Tomatoes originally hail from Mexico and love warmth and sunlight above all else. Find a spot for them that gets a full day of direct sunlight.

 3. Prepare the soil. Tomatoes are heavy feeders, meaning they take up more nutrients from the soil than other plants, without putting much back in. If possible, do not grow tomatoes (or any Solanaceous plants) in the same location season after season. Rotating your crops and growing Solanaceous crops in the same spot no more than every three seasons reduces the spread of disease from year to year. When planning your rotations, keep in mind that too much nitrogen will result in large, leafy plants with few fruit. If a nitrogen fixer, such as a legume, was grown in your tomato bed the season before, do not plant a tomato (or any other vegetable that is harvested for its fruit) there. Wherever you grow them, be sure to provide rich soil. Compost or aged manure can be spread over whole tomato beds, or around each individual plant.

4. Choose a cloudy day, or the cool of evening. To alleviate seedlings from shock, transplant on a cloudy day, or if it’s not in the forecast, plan toward the end of the day, when air and soil temperatures cool and the sun is won’t scorch the young plants.

5. Give space. Air flow is the most vital factor in preventing tomato blight, other fungal diseases, and even the spread of pests. Although in June, it may be tempting to squeeze as many tomatoes as a limited garden bed will allow (fueled by dreams of limitless summer salads or homemade tomato sauce through the winter) adequate spacing will pay off come harvest time in August.  We plant our tomatoes two feet apart.

6. Clean up. Before putting tomatoes in the ground, snip off the bottom-most branches and leaves of the seedlings. You’ll see why in step 8.

6. Un-pot carefully. When taking seedlings out of their pots, don’t break the roots. Place a closed palm over the base of the tomato with the stem sticking out in between your fingers, then use the same technique as building a sand castle using a bucket shape: tip the pot upside down, tap on all sides and bottom to loosen the plant’s grip, and gently pull the pot up to separate. If this doesn’t work, consider cutting the pot away – just don’t pull on the plant itself.

7. Tickle the roots. Loosening the roots will help the plant acclimate faster thus resulting in speedier growth, while but breaking the delicate roots will weaken the plant. To strike the right balance, gently wiggle your fingers through the outer edge of the roots to loosen them just slightly.

 8. Plant deeply. Have you noticed the layer of fuzzy hairs at the bottom of tomato seedlings?  Those will grow into roots if they are below ground. Burying the little fuzzy hairs will give your tomatoes a stronger root base, preventing them from toppling over in the wind and allowing them to pull more nutrients up from the soil. However, planting deeper than that, or burying the bottom leaves and branches could result in fungal problems.

9. Water when dry. Regular watering is important, but overwatering can increase the change of disease. Water your seedlings heavily immediately after transplanting; then hydrate them only when the soil dries out. The surface of the soil can dry quickly, but that doesn’t always mean all moisture is gone. To check, stick your finger in the ground: if it comes out wet, the plants still have some water to draw from; if it’s dry – it’s time to water.

10. Stake up. Setting up a structure right away for the tomatoes to climb and lean on when they get bigger will help avoid bad timing when the plants are big enough to climb. Getting this done immediately will also prevent any root disturbance. Tomatoes are divided into two categories: determinate and indeterminate. Determinate varieties are bushy and lower to the ground; they stop growing when the top bud sets fruit and all the fruit from one plant ripens within a couple of weeks. They benefit from some support – a tomato cage, stakes, or similar structure works well. Indeterminate varieties are vining: they will keep growing, continually producing new flowers and setting new fruit until they are killed by frost. Indeterminate tomatoes need a solid trellis-like structure to climb up. For more information on tomato trellising, take a look at Ken’s Tomato Trellising Basics.

Don’t forget to regularly check in on the young plants and monitor their health and growth. Stay on top of pest and weed watch – this is particularly important in the seedling stage, as the plants are too little to compete with persistent weeds and early season pests like cutworms and flea beetles. And, above all, remember that plants want to live. All we, as gardeners, can offer them is a healthy and caring environment to inhabit.

More helpful tomato and transplanting resources:

Tomato Pruning

Troubleshooting in the Tomato Patch

Transplanting and Troubleshooting

Three Ways to Choose Tomatoes for your Garden

8 thoughts on “10 Tomato Transplant Tips”

  • Ashling

    Wow....could have used this post before transplanting 36 tomato plants yesterday!! Can see at least three things I did wrong. Sigh.

  • Kathy Carver
    Kathy Carver 05/28/2013 at 10:02 am

    I am wondering why it is not a good idea to plant a fruiting crop following a nitrogen fixing crop that was grown over the previous winter. I was not aware that it was a problem. Please enlighten me!

    • Green Thumb

      too much nitrogen will prevent uptake of other essential nutrients, specifically those needed for flowering, calcium, magnesium, phosphorus, potassium.

  • elizabeth Blackburn
    elizabeth Blackburn 05/28/2013 at 6:03 pm

    Any suggestions on preventing flea beetles. We have been hard hit this year on almost every crop. We are sick of dusting.

  • ken

    They said not to plant tomatoes too many years consecutively in the same location. Your comment above suggests the right thing to do. Crop rotation is good. Thats good kathy

  • Michelle Elliot
    Michelle Elliot 05/29/2013 at 3:10 pm

    Since I've moved to NY from California several years ago I have been growing toms from seed...using your seeds which have grow magnificent tomatoes. This year I'm trying something that I did only once in California (not with tomatoes)....a "lasagne" bed....alternating layers of nitrogen (green grassclippings/compost) with carbon (dry leaves,dry grass) On the top of this layering I've put organic soil from compost and mulch. You can do all this layering without ever disturbing the soil....encouraging the earth worms up to make more soil and saving my back. And you can plant as soon as you've made the rows....only seedlings, not seeds
    My concern is... now that I've actually done this..now that the little tomato seedlings are planted in these beds...will the roots be able to grow through those leaves or will they get choked off? I guess time will tell.
    Do any of you have any experiences/advice with this type of gardening?

  • John

    @Michelle, I'm sure you found out that they will surely grow through it while consuming it. Plants will grow their roots around rocks and stones, they're going to appreciate the decomposing plant food you put into your bed.

  • Michaela

    Can you please advise when would be a good time to plant seedlings outdoors in a zone 6/7 coastal climate. I was hoping to protect the plants with hoops and plastic cover for the first month until there is no sign of frost but can't really figure out when I could do that.
    Greatly appreciate your help.


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