When Should you Transplant Seedlings to Bigger Pots?

Transplant Seedlings
Seedling Tray

For some exotic and tropical plants, it may be satisfying enough to simply germinate seeds into seedlings. Now, your task at hand is transplanting them to bigger pots.  This will soon be
a concern if you don’t sell or give away them for a while.

When should you transplant seedlings into bigger pots?  The answer is you can transplant them usually when the first set of real leaves have emerged (after the embryonic leaves, also known as Cotyledons and seed leaves).

There are a few more important steps to follow to ensure your plants survive this stage, so let’s dig a little deeper into this subject, shall we?




What Are the First True Leaves on a Seedling?

The first true leaves of a seedling are not the first signs of a sprout you see coming up from the soil.  The very first plant material that comes up from the soil is known as Cotyledons.  These are also called seed leaves or embryonic leaves.

So, the first true leaves of a seedling are the next leaves that come up after the Cotyledons emerge.

When Can I Safely Transplant My Seedlings?

The germination period for plants can vary greatly – especially with unusual and hard to find plant species. Some seeds may germinate in days, others may take weeks or months to germinate.

Because of this, there isn’t a set time frame to when you should transplant your seedlings.  The general rule of thumb is the earliest you want to do so is when the first set of true leaves emerge after the Cotyledons.  You may want to wait until the second or third true leaves emerge to have a better success rate.

You will likely develop a sort of sixth sense and have a gut feeling about this when you watch your plants grow.  You’ll probably notice that their growth may slow down or just by eyeballing it looks like it is ready for a new container.

If you started your seeds in a seedling tray with individual cells you can wait longer as you don’t have to worry about roots getting tangled up.  Tangled roots may happen if you plant a bunch of seeds in a big tray or pot that requires you to thin the plants out by hand.

If you planted in a way that requires you to thin the seedlings out by hand, you will want to do so after the first set of real leaves emerge so you can avoid the possibility of having to untangle the seedling roots.

Note on Delicate Plant Species

Of course, if you are working with a species that is known to have a delicate root system, simply be extra careful and it may be a good idea to make sure the plant has adapted to its current habitat before moving it to a new home.  For some rare plants, be sure to do a little extra research on that exact species in case special instructions are recommended.

What Size Pot Should I Use When Transplanting?

You may wonder what size pot you should buy when transplanting to a larger container.  Basically, all you need to do is pick the pot size that is the next size up from the current one.  Look for a container that is roughly 25% bigger than your current one.

Can I Start My Plants in a Big Pot Instead of a Seedling Tray?

It may be tempting to want to bypass small pots and go directly to a large pot.  You don’t want to do this though as larger pots simply hold more water.  Too much water can be a bad thing for the roots – complications such as damping off disease (fungi that can kill or weaken seedlings) can occur.

Should I Transplant Directly to Garden or a Larger Pot?

The answer to this question will vary on what you are trying to grow.  If you are growing simple vegetables for an outdoor garden, then it’s not going to be as big of a deal to plant directly to the garden.  Of course, this also depends on what the weather is like, the planting calendar has the last frost arrived, etc.

For most tropical plants, you will probably want to move them to a larger pot – simply because more than likely they will be for decorative purposes or if you live in a colder climate so you can move it inside and outside depending on the weather.

If you live in a tropical plant hardiness zone, then you are probably ok to plant directly in the soil.  But if it were me, I would put in a larger pot to make sure the plant has adapted to the environment and appears to be fairly stable.

This is also known as hardening off your plants.  Keep them in pots until they are used to the local environment and then plant in a garden or soil.

A Few Tips on How to Transplant Seedlings

  • When removing a plant from a seedling tray cell or other small starter pot, do not pull the plant by the stem to remove it.  Turn the container upside down while holding the top of the soil – then gently squeeze the plastic cell sides to loosen it.  It should then easily fall or slide out.
  • If you are using biodegradable peat pots, you may wonder if you can plant the peat pot into the soil of a larger pot or if you need to remove the plant from the peat pot.  If moving to a bigger pot, I recommend removing the plant as it will allow the roots to have more freedom.  However, if you are transplanting a plant in a peat pot to a garden then it’s no problem keeping it in the peat pot.
  • When planting biodegradable peat pots in the garden, maximize the plant’s health and success by removing the top edges.  If you do not remove the top edges, it acts as a wick and can dry the soil out near the roots.  The entire peat pot should be under the soil line.
  • Dig a hole the same depth as the original pot you are transplanting from.  Make sure the hole is also wider than the original pot – perhaps at least 50% or so larger.
  • When you have removed a plant from the seedling container, you may wish to squeeze the root system a bit to loosen it up before planting.  For really tough plants you can even untangle the roots to make their life easier at their new home.
  • Make sure the very first seedling leaves are above the soil line.  Not the real leaves, but the first Cotyledons when it sprouted.
  • As always, check the upcoming weather and Farmer’s Almanac for advice on when to plant outside.

Conclusion

For some plant species, it may take a long time for seeds to germinate.  A good example of this is the coffee plant, which can take several weeks to germinate.  If you make it that far, you don’t want to have to start all over from scratch and replant again.  Make sure you are careful when transplanting and soon your tiny seedlings will be beautiful houseplants to show off to friends and family.

1 thought on “When Should you Transplant Seedlings to Bigger Pots?”

  1. ive just planted 238 sunflower seedlings measuring 5 inches tall with their 2nd and 3rd leaves , from large industrial size seed tray into individual pots. I dont have grow lights (yet) and living in UK , the weather isnt sunny enough to plant outdoors for 2/3 weeks. Where should I now place them? Thanks

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