How to Repot and Transplant Tomato and Pepper Plants (Upsizing)

If you start seeds yourself rather than purchase plants one important step in the process is transplanting. Repotting and transplanting tomatoes and peppers allows them to grow larger root systems so that when you do plant them in the garden they are more established (upsizing). There are a few tips that I want to share with you when transplanting your tomatoes and peppers.

Transplanting Tomatoes and Peppers

Pepper plants after repotting into coir pots.

Use Good Soil for Transplanting

When starting seeds you probably used a seed starting mixture that did not contain soil. Those mixes are great for starting the seed since they are pH balanced and are generally disease free. Now though it’s time to get the seedlings into something more nourishing. There are basically two ways you can choose your soil, make it yourself or buy it. Let’s look at each of these choices.

Choosing the Right Soil

If you choose to buy your own soil you can save a lot of time and make the transplanting process easier overall. I always recommend leaning toward organic or natural soil mixes.

Making your Own Potting Soil

To make your own potting soil there are just a few ingredients. There are a lots of methods and recipes for soil but here is one I have used for a while.

A Simple Soil Recipe for Transplants

1/3 Compost, 1/3 peat, 1/3 perlite, amendments (see below), lime (roughly 1 TBS per gallon of peat)

When making soil for transplants the goal is loose, nutritious soil with a good pH (per hydrogen, a measurement of acidity). Since I use peat for the soil the acidity always needs balanced with lime. If you forget the lime (which I’ve done before) your tomatoes will show strange purple coloration. You can correct this by adding a little lime to the soil.

Soil Amendments

For soil amendments I use a general garden fertilizer that has a balanced NPK ratio (Nitrogen – Phosphorus – Potassium). Depending on the plants I am transplanting I may add a little bonemeal for extra calcium and phosphorus or bloodmeal if I am wanting more stem and foliage growth.

When I transplant peppers and tomatoes I do use a little bloodmeal in the mix. At the beginning of the season I like for them to put on some stem and leaf growth but I am careful about how much I add since I am not growing them for their foliage.

Soil Amendments I use (Am. Aff.):

Best Pots for Transplanting Tomatoes and Peppers

I’m a fan of using biodegradable pots for the transplanting process. Using a type of biodegradable pot like peat pots, cowpots, or coir pots means when it is time to plant your tomatoes and peppers in the garden there will be little to no root disturbance for the plant.

Coir pots made from coconut shells

For the second stage of growing tomatoes and peppers from seed I recommend using 4″ size pots but 3″ pots will work OK too. That should be enough of an upsize to have some good root growth between the seedling stage and final planting in the garden. 4″ pots allow me to fit 18 plants in a 1020 flat.

Product Links (Am. Aff.): Cowpots, Coir Pots, Peat Pots

The Process Repotting and Transplanting the Seedlings

Since I grow my seeds tightly in plastic cup greenhouses I have to separate the seedlings. To make the separation easier I water just before transplanting which also helps keep them moist during the transplanting process.

Then I take the entire cup and squeeze the sides a little to loosen the soil inside. Next I dump the cup gently onto a seed tray so the soil doesn’t go everywhere. That soil can be tossed in the compost bin when you are finished

When the seedlings are laying on the tray gently separate the seedlings from the soil. Tomatoes and peppers will root along their stems and branches which makes the next step important.

Take each seedling and plant it by itself in a pot. When you plant the seedling do it so that the roots touch the bottom of the pot and as much stem is buried and covered in the pot. If the plant is not large enough to reach the bottom of the pot that is OK, just plant as much of the stem as possible and leave a few leaves above the soil surface (2-4).

The goal is to encourage more roots to form and this will help insure a significant root ball. I have had a lot of success with repotting and transplantng my tomato and pepper plants using this method.

If you start the seedlings out correctly and give them every benefit at the beginning they will flourish.

See the Transplanting Process

Harden Off the Seedlings

After transplanting your plants into larger pots then next step in growing your tomato and peppers plants is to harden them off. Hardening off is the gradual process of getting the seedlings acclimated to the outdoors.

Avoid Sunscald and Stress

Seedlings that are suddenly moved into the sunlight and left to adapt on their own can face sunscald and can be severely damaged from that stress. That doesn’t mean they can’t recover from sunscald but if you can gently adapt the plants to the outdoors they will do better with less stress (on them and on you!)

Jalapeno pepper plant freshly transplanted and watered.

Short Periods of Time Outdoors

Bring the seedlings outside for a short period of time each day for a few days. Start with somewhere around 20-30 minutes in the sun then bring them back indoors or put them in a shady spot. Each day bring them outdoors for a little more time until they are well adapted. The exact daily time for hardening off the seedlings is dependent on the weather so it can vary.

Overcast Days are Awesome Sometimes!

I love overcast days for transplanting! On a cloudy overcast day the seedlings can stay outdoors longer than on a hot sunny day. Use good judgement and pay attention to the weather conditions. If it is going to be extremely warm limit their exposure.

It takes about a week to ten days to harden off seedlings without damaging them. Make sure throughout this process the tomatoes and peppers are well watered so they have everything they need for success.

For my purposes I moved my flats into our greenhouse. I put them on a shady shelf where the plants would be screened from direct sunlight.

Planting Tomatoes and Peppers in the Garden

When your plants are ready for transplanting to the garden read this post:

The Best Way to Plant a Tomato. I’ll give you a hint – it’s all about those roots!

Or maybe go ahead and read it now. 😉 Thanks for visiting and sharing!