As an Amazon Associate I earn from qualifying purchases.
You can read my full disclosure statement here.
Today we will be talking about how to transplant tomato seedlings, in order to have them grow into huge, healthy productive tomato plants!
(Update April 2020) It is that time of the year, where it is time to transplant tomato seedlings into their final spot for the summer growing season. In this article, I will share with you tips on how to transplant tomato seedlings whether you plan to plant them in pots or the traditional way in the ground.
How to Transplant Tomato Seedlings
Getting your tomato starts planted correctly is the key to growing healthy tomatoes and getting a great harvest. We will cover how big your tomato seedlings need to be before finally transplanting them outdoors, how to harden them off before planting them, how to prepare them before planting, which supplements to use when planting, how to prepare the seedlings prior to transplanting them and finally, different ways to plant them in the garden.
When Are Your Tomato Starts Big Enough to Transplant
If you started tomatoes by seed in small cells, and need to up pot them before their final transplant to the garden, you want to wait until their second set of leaves have come in at a minimum. The tomato seedlings are big enough to be planted in the garden, when they are about 4-6″ tall. But wait! Make sure the outdoor conditions are suitable first, and be sure to harden them off first.
Can You Safely Separate Tomato Seedlings?
If you planted multiple tomato seeds in each cell and more than one has germinated, yes, you can safely separate them and transplant each one into its own new pot. Simply pinch the seedlings apart at the base of the plant, right where it comes out of the soil. Gently pull the roots apart and walla! You now have two seedlings to plant! Check out my article on How to Get Free Tomato Plants from Cuttings for another way to multiply your tomato plants easily!
When is the Right Time to Plant Tomato Seedlings Outside?
Tomatoes are a heat loving plant, and do not do well when the temperatures go below 50 degrees. Often times, even after your average last frost date, the temperatures will dip well below 50 degrees at night.
Here in our garden zone 8b near Seattle, we wait a month after our last frost date of April 15, and will only plant them outdoors from May 15th or later. But always check the long range weather forecast before you plant, to make sure you are not going to get an unexpected cold spell.
Also, ideally wait for a couple of days of overcast weather. If you plant them on a hot sunny day, the heat and the sun could cause them to go into shock. Gray overcast days give them a bit more time to settle into their new home and they transition easier.
Hardening Off your Tomato Seedlings
Before moving your tomato seedlings to their permanent location outdoors, they need to be hardened off. This means that they are slowly and gradually allowed to accustom themselves to real outdoors conditions rather than the sheltered and stable indoor conditions that they have been growing in from seed.
Start by moving your seedlings outdoors into a sheltered area, away from wind and hot direct sun, for an hour or two the first day. Three to four hours the second day, increasing the time by a little bit more each day until they have been outside all day.
Same goes for exposing them to full hot sun. Don’t move them from the sheltered location, into a full day of hot hot sun. They will get sun scald and may go into shock. Slowly allow them to become accustomed to the direct sun as well. For a full understanding of how and why you need to harden off your seedlings, check out my article How to Harden Off Your Seedlings.
Preparing the Tomato Seedlings for Transplanting
Once the seedlings have been hardened off, it is time to prepare them for their transplanting. Prior to transplanting your tomato seedlings, give them a good drink of water. I always water my tomato seedlings in trays from the bottom because they don’t like to have their leaves wet. By giving them a good drink ahead of time, this will help prevent them from struggling, or going into shock, right after they have been moved. Also, remove all the extra lower leaves, just leaving the top two clusters of leaves.
How Deep Do I Plant Tomato Seedlings?
At planting time, you will want to bury as much stem as possible, as the tomatoes will grow new roots along the lower stem and from the leaf nodules where you removed the lower leaves, to make for a stronger plant. I just use my thumb finger nail and pinch those bottom leaves off as close to the stem as possible. Be careful not to bend or fold the main stem while doing this.
Choosing to Plant Tomatoes in a Pot or in the Ground
I live in a cool, short growing season here in the Pacific Northwest. Because of this, I plant my tomatoes in pots because it allows the plants to get warmer, roots and all, which they like. If you are planting into the ground, make sure to choose an area you have not grown night shades in for the last 3 or 4 years. Nightshades include tomatoes, potatoes, peppers and eggplants. Make sure the area gets a full day of sun and that the soil is well draining, and mix in some good compost. Plan to space your tomatoes at least 24″ apart, more space is better. They need good air circulation around each plant.
Trench Planting your Tomatoes
I’m going to talk about this option for a minute because a lot of people are unfamiliar with it. Trench planting your tomatoes is exactly how it sounds. Traditional planting of a tomato plant into the ground, consists of digging a deep hole and dropping your tomato plant down 12-18″ into the hole. For trench planting, you dig a shallow trench the length of the main stem + the root ball of the plant, about 6-8″ down. Place the supplements down at the bottom of this trench, along the length of it. Sprinkle 1-2″ of soil over the supplements. Then you will lay your tomato plant down into the trench on it’s side, holding the top cluster of leaves above the soil by bending them slightly upwards.
Than bury the entire stem and root ball with soil. This allows for the entire root system of the plant, to be closer to the surface, therefore WARMER. If you live in a cooler climate like I do, this is critical for growing a good crop of tomatoes. If you live in a HOT DRY DESERT climate, this is not a good idea, as the roots will dry out in no time.
Preparing the Planting Pots for Tomatoes
I like to use pots that are 4-5 gallons in size for my tomatoes. To get them ready for planting, I wash them all well. Then I sanitize all my pots by dipping them in a bleach/water solution in a large plastic bin. To sanitize, I put in a couple of inches of water and maybe 2 cups of bleach. Than dip each pot in and roll it in the bleach/water solution, than let it air dry in the sun.
For potting soil, in the past, I have always used the Organic Miracle Grow Moisture Control Potting Soil which I bought at Costco. Having moisture control in the potting mix, helps to prevent the pots from drying out too quickly, so look for that in the potting soil you choose.
You might wonder where to get pots, as buying them is money that I’d rather use elsewhere. I’ve gotten most of my pots for free, utilizing local Facebook homesteading and gardening groups. Or look for Buy Nothing type groups or on Craigslist. You can often find people giving them away for free! It doesn’t hurt to ask at your local nursery too.
Supplements to Include When Planting Tomatoes
For either planting in the ground or planting in a pot, I mix in 2 TBSN’s of organic vegetable fertilizer, 1 TBSN of Epsom salts and 1 TBSN of crushed eggshells. See my article How to Use Egg Shells in the Garden. If planting in a pot, fill the pot. about 1/4-1/3 full with the potting soil you are using, add all these supplements, and mix well. Make sure the supplements are a few inches below where the actual plant will be, whether you are planting in a hole or in a trench.
Tips on Planting your Tomato Seedlings
Whether you are planting in a pot or in the ground, at this point it is the same. First, dig a hole, deep enough for the majority of the stem and root ball to be planted. Put the supplements in the bottom of the hole and mix well into the soil. Place the plant gently into the hole, and gently add soil to bury it while you hold the plant upright.
If planting in a pot, leave a good 2″ at the top of the pot free of soil. This is so when watering, the water will stay inside the pot and not run off the top surface. If planting into the ground, mulch around the base of the plant to help keep the soil from drying out quickly. Mulch also prevents mud from splattering up onto the plant foliage, which can cause blight and other viruses that live in the soil.
Supporting the Tomato Plant
It is a good idea to provide some type of support for your tomato plant to climb at this point. Don’t wait until the roots have spread and risk damaging the plant by pounding a stake in later. Do it now.
There are many many methods for supporting the tomato plant. I will have to do another post on this now come to think of it! There are tomato cages, the string method, home made tomato supports of all kinds. Think about what you plan to use before you transplant them so you will have the supplies you need on hand.
Caring for Freshly Transplanted Tomatoes
After planting, give a good deep watering to help get all those new roots growing. Then water regularly, waiting until the top 1″ or so of soil is dry. If you wait too long, and water sporadically, this will cause your ripening fruit to split.
I then mix a solution of water, Epsom salts and fish emulsion fertilizer (one TBSN of each per gallon of water) and spray on the plants once a month using a garden sprayer. Spray early in the day on a cloudy day. This allows the plants have time to dry before the cooler evening air sets in.
If sprayed on a sunny day, the solution can burn the plant. I do this fertilizing all the while the plants are flowering to set new fruit. Later in the season, when there is more fruit setting than flowers flowering, I let up on the fertilizing.
Good Luck with Transplanting Your Tomatoes!
This is how I have been transplanting my tomatoes for a number of years with great success. I hope that it works for you just as well. If you have any further questions, please let me know in the comments. Thanks so much for stopping by, I wish you all a very plentiful tomato harvest this year!
My Other Articles on Growing Tomatoes:
And lastly, see How I Make Money Selling Tomato and Pepper Plants
I hope this was helpful! Please let me know if you have any questions on planting your tomato seedlings!
Want to Remember This?
Please pin my “How to Transplant your Tomato Seedlings” article to your favorite gardening board on Pinterest!