How to Know If You Should Up-Pot Your Seedlings

What does it mean to up-pot a seedling?

To put it simply, up-potting or potting up, means that you will be transplanting your seedlings from whatever pot or tray you started with, to a larger container before you plant them in the garden. Many people start seeds in a commercial seed starting tray with tiny cells. These cells are not big enough for most seedlings to thrive in between the time it takes for them to germinate to the time at which you plant them in the garden.

Do all seedlings need up-potted?

The short answer is: No.

You do not need to up-pot your seedlings if:

You will be planting them in the garden within the next week
Their roots are not poking out of the bottom of their cell
They continue to vigorously grow in their current container
They show no sign of nutrient deficiency
You started them in a large container or pot (like a red solo cup)

I do not up-pot my onions or kale. Once they’ve outgrown their cells I plant them directly in the garden.

How does one know if seedlings should be up-potted?

You should up-pot your seedlings if you can’t plant them in their final garden spot within the next week AND:

They have lots of roots spilling out of the bottom of the seed cell
You can easily pull the seedling out of it’s cell or current container and you see mostly roots with no loose soil

I always need to up-pot my tomatoes and peppers.

How does one up-pot their seedlings?

When you up-pot your seedlings you should use normal potting mix, NOT, seed starting mix. At this point in time the seedlings need nutrients to continue to thrive.

To up-pot:

Fill a container that is at least twice as big as your current container, but preferably 3-4 times as big, half way with potting mix.
Gently remove your seedling from it’s cell and place it in the middle of the new container.
Add more soil to the container so that it is surrounded on all sides.
Water your seedlings in their new container.

For best results, do not bury the seedling’s stem. Some plants are very sensitive to the height at which they should be planted.

How many seedlings should there be per container?

For best results, one seedling should be planted per container. This will allow the seedling to have maximum nutrients and room to grow. Seedlings will become bigger and stronger with appropriate nutrients and more space.

That being said! If you don’t have enough containers, you can plant more than one seedling per new container. Just try to plant your seedlings on opposite sides of the new container so that they have maximum room to grow.

What now?

Now that you’ve up-potted your seedlings, adjust your light so that it is still 2-4 inches from the tops of your seedlings. Continue to follow the Seven Steps for Super Strong Seedlings by bottom watering your seedlings and occasionally pointing a fan at your seedlings until it is time to harden them off!