Repotting seedlings is important in order to grow strong plants for your garden. In this post I will talk about the benefits, and tell you when to put seedlings into pots. I’ll also show you the best types of containers and soil to use, and give you step-by-step instructions for how to pot up seedlings.
Repotting seedlings is exciting because it means your plants are growing! Moving them into bigger pots means larger, healthier plants for your garden!
This isn’t a required step in successful seedling care. Many seedlings will grow just fine without being repotted.
But they can start to suffer if they’re left pot-bound in those tiny seed cells for too long, which can stunt their growth.
It’s important to learn the signs to look out for, so you’ll know exactly when to move seedling to bigger pots.
Do Seedlings Really Need To Be Repotted?
The short answer is No. Not all seedlings need to be repotted. Potting up seedlings is an optional step, and is not required for each and every plant.
In fact, you should only pot up seedlings if they need it. Do not try to repot tiny or immature seedlings (e.g.: seedlings that don’t have a lot of growth, or haven’t grown their true leaves yet).
Some seedlings will be just fine staying in the seed trays all the way up until you move them outside. But others will suffer if left pot-bound in those tiny seed cells for too long.
The larger the seed, the more likely it is that you’ll need to pot them up. Seedlings that start as teeny tiny seeds may not require repotting.
Large seedlings on the other hand will grow best if they’re moved into bigger containers as they mature.
Benefits Of Repotting Seedlings
There are many benefits of potting up seedlings, and it’s a great way to ensure your seedlings grow strong and stay healthy.
Potting up seedlings gives them more room to grow and mature. If seedlings are pot-bound in those small trays for too long, it can stunt their growth.
Planting seedlings into pots will also give them plenty of room to mature into small plants by the time they’re ready to be planted into the garden. This gives them a much better chance of success!
Seedlings growing in their own pots will also help increase airflow, which lowers the risk of mold growth. Plus, they won’t be competing with each other for light and fertilizer once they’re out of the seed trays.
When To Repot Seedlings
So how do you know when to pot up seedlings then? There are several signs to look out for so that you know exactly when to move seedlings to bigger pot.
It’s time to pot up seedlings when…
- they have grown to be twice as tall as the height of the container they’re in
- there are a lot of roots growing out of the bottom of the seed cells (i.e.: they’re pot-bound)
- they’ve stopped growing larger, or their growth is stunted
- the soil dries out so quickly that you have to water the trays daily (or more!)
Seedlings ready to be potted up from seed tray
Best Potting Soil For Seedlings
When it comes to the type of soil to use for potting up seedlings, you have choices. You don’t have to buy any special seedling potting soil, you can use whatever you have on hand.
Leftover seed starting soil works great, or you can mix up a batch of your own if you have the supplies on hand. You could also use regular potting soil.
Just make sure the soil you choose isn’t too heavy (and never use garden soil!). It’s best to repot seedlings using a lightweight soilless mix so their roots can grow easily.
Also, don’t use any type of soil that has fertilizer in it, because it can harm sensitive seedlings.
Different Types Of Seedling Containers
When it comes to choosing the best type of container to use for potting up seedlings, there are a few things to keep in mind.
Choose a container that’s about twice the size of the seed cells (a 3-4″ pot size usually works great). And always be sure any plastic containers you choose to use have drainage holes in the bottom (or poke the holes yourself).
At a super high level, there are basically two types of containers you could use to pot up seedlings: non-plantable or plantable pots…
1. Non-plantable Pots
These types of pots are usually made out of plastic. You can reuse some of them year after year, while you make others yourself out of recycled materials. Here are a few examples:
- Reusable plastic nursery pots
- Plastic cups
- Yogurt containers
- Bottom half of plastic water bottles
- Other small plastic containers you can find in your recycling bin
2. Plantable Pots
Plantable pots are made out of biodegradable materials, and you can plant them directly into the garden. Here are some examples of each:
- Coco coir pots
- Recycled paper pots
- Peat pots
- Containers made out of other organic materials (like cow manure pots!)
- DIY newspaper pots
Types of seedling pots
How To Repot Seedlings Step-By-Step
Once you determine which of your seedlings need to be repotted, it’s time to get them ready for their big move. To make it easier on them (and on you), water your seedlings several hours before you pot them up.
A moist rootball will hold together better than a dry one, making it easier. Ensuring your seedlings are well hydrated will also minimizing the risk of transplant shock.
Follow these easy step-by-step instructions for repotting seedlings into larger containers…
Supplies Needed For Potting Up Seedlings
You don’t need a lot of supplies for potting up seedlings. Heck, you may already have many of these items laying around the house. Here’s what you’ll need…
- Seedlings
- Pots
- Potting soil
- Trowel or spoon
- Potting tray (optional)
- Tray for seedlings after potting
- Plant tags or markers
Planting seedlings into larger pots
Steps For Repotting Seedlings
Before you begin repotting seedlings, you might want to lay down a towel or a large bed sheet to catch any mess, and make cleanup easy.
Step 1: Get your stuff together – It’s best to have everything ready to go before you get started.
When I have a bunch of seedlings to pot up, I use an assembly line method. I fill each container with about an inch of potting soil, then line them up to get them ready.
Step 2: Remove the seedlings from the seed cell – The key to this step is to be gentle and take it slow. Start by placing your fingers on either side of the stem, then flip the seed cell over. Squeeze the bottom of once cell until the seedling comes loose.
Make sure you don’t pull or grab the seedling by the stem to remove it. If you are having trouble, you can use a spoon, butter knife, or skinny trowel to pop the seedlings out of the cell.
Removing seedling from the seed cell
Step 3: Straighten the seedling roots – If the seedling roots are growing in a circular pattern or are tightly root-bound, then gently tease them apart to straighten them. Take care not to break off any roots in the process.
If there’s more than one seedling growing in a cell, then gently tease the roots apart to separate them. It’s important to plant each seedling into its own pot.
They’ll be too crowded and won’t have enough space to grow if you don’t separate them.
A slightly pot-bound seedling with circular roots
Step 4: Fill the pot with dirt – Place the seedling into the pot at the same depth as it was growing in the seed cell (i.e.: don’t bury the stem). As you work to fill the pot, lightly pack the soil around the seedlings rootball with your fingers.
Gently pack the soil as you pot up seedlings
Step 5: Add a plant tag – Adding a plant tag to each pot will help you identify your seedlings later. If you don’t have plant tags, you can write on the side of plantable pots with a marker or paint pen.
Or put a piece of tape on your plastic containers, and write on that (I like to use painters tape because it’s easy to remove later).
Step 6: Water the seedlings – Gently water each of them. It’s normal for the dirt to settle after you water them. If that happens, simply add a little more to top off them off.
Seedlings repotted into larger containers
Caring For Newly Repotted Seedlings
Once you have your seedlings potted up, there is a chance they will go into shock. That means they may droop for a few days after being repotted. Don’t panic if this happens! It’s common and fixable.
Just put them under the lights, keep the soil consistently moist, and hold off on fertilizing until they recover. They should pop back up and look healthy again in a few days.
Repotting seedlings is a wonderful way to ensure that you grow strong, healthy seedlings for your garden. Once you learn the signs to watch for, you’ll know which seedlings need to be potted up, and exactly when to move seedlings into bigger pots.
Up next: Learn exactly when & how to transplant seedlings into the garden
If you’re tired of struggling to learn how to grown seeds by trial and error, then you should take my online Seed Starting Course! It’s a fun, self-paced online course that will teach you everything you need to know in order to grow amazing seedlings for your garden. Enroll and start today!
Or, if you just need a refresher or a quick-start guide for planting seeds indoors, then my Starting Seeds Indoors eBook is what you need.
More Posts About Seedlings
Share your tips for repotting seedlings in the comments section below!
Richard Sawatsky says
I planted tomatoes in a starter pot that has 40 cells and lighting. I’m in my first week and they are touching the top of the starter pot. I have raised the top with styrofoam. What should I do know. I am a total ametuor and should I pull the seedlings when there are more than one in the pot and what should I do to provide light and keep them growing.
Amy Andrychowicz says
If you have more than one seedling in a pot, then it’s best to thin them out to keep only the healthiest one. Some people have success separating tomato seedlings and potting each one up individually, but doing so may cause fatal damage to the delicate roots or stems. Here’s more information that will help you out…
How To Grow Tomatoes From Seed
How To Take Care Of Seedlings & What To Do After They Sprout
Sarah says
I’m about to repot into larger containers and have a question about the soil medium. I bought some organic Promix, worm castings, and perlite. Figuring I can incorporate the seedling mix I used for the seeds into this, would this be a sufficient amount of nutrients for the plants?
Amy Andrychowicz says
I’m not familiar with that specific brand of soil, so I can’t speak from experience. But if it’s peat-based, then you should use a pH probe to test the acidity. It totally depends on the type of seedlings you’re potting up, but many types of veggies and other plants like alkaline soil, so you may need to add a bit of garden lime to neutralize the acidity. Otherwise, your mix sounds like it will work great. Check out my seedling care guide for details on how to care for them, including tips for fertilizing them for added nutrients.
Andrew Millier says
Thankyou for a great item about seedlings, Im feeling nervous about when to pot mine as they seem so small and frail, they are now about an inch tall, but are really tiny. But I dont want to lose them , Just have to be brave I guess.
ps. they are carnation seeds.
Bye for now,
Andy
Amy Andrychowicz says
You don’t need to pot up all of your seedlings. The small ones can just stay in the starter trays until they’re large enough to transplant into the garden.
Linda Zarate says
Linda says
The stem of my seedlings are so thin and the leaves so small after 10 weeks from the starting point. It seems that they are not strong enough to be re-potted. I am sure that the roots have not gotten strong either. What have I done wrong?
Amy Andrychowicz says
When the stems of seedlings are thin, then it usually means they aren’t getting enough light. If they aren’t growing any bigger, it usually means they need more heat and/or fertilizer. Here’s a detailed post that will help you out… How To Take Care Of Seedlings & What To Do After They Sprout.
Parrish Nored says
Why not just start your larger growing seedlings in larger seeding pots to eliminate the need for repotting? I am about to do seedlings for my Fall garden. WDYT?
Amy Andrychowicz says
You could certainly start your seeds in larger pots rather than repotting them later, if that works for you. But it is easier to germinate seeds in seedling trays. Repotting isn’t always necessary either. You could transplant the seedlings directly from the seed trays into the garden once they grow big enough. Repotting them just gives them more time to grow larger before transplanting into the garden.
Kristen says
I have a question, you say if you have more than one seed in a cell, to separate them. Each plant gets its own pot. What if you used the peat pellets. How do you go about this? And another question regarding the pellets. How do you keep the seed’s roots from going into another pellet? I tend to mix trays with different things.
Amy Andrychowicz says
I recommend thinning the weakest seedling because trying to break apart the peat pellet may be too hard on the seedlings, and end up damaging them beyond repair. If the seedling roots are growing so long that they’re growing into neighboring pellets, then you should definitely pot them up. In fact, they should be potted up before it even gets to that point. Otherwise, you could try spacing the pellets a bit further apart in the trays to keep the roots separated.