Potting Up Seedlings

March 12, 2011 at 6:08 pm 4 comments

I spent some time today potting up the impatiens that I’d sown in a flat. I thought I’d share my technique. Potting up isn’t rocket science, but I might be able to impart a few tips and tricks to help you transition your seedlings from crowded flats to larger single containers.

The first question I consider is whether my seedlings really need potting up. If they’re looking healthy and seem to have room in their existing flat, I’ll usually save myself the hassle and leave them until I can put them directly into the ground or their permanent containers. But if things are looking crowded, and you see signs that your seedlings are becoming stunted or root bound (roots coming out the bottom of the container’s drainage holes, or circling the inside of the container’s walls in a tight knot), and if planting time is still a ways off, you may want to give your seedlings a leg up by transferring them to larger containers for a while.

Such was the case with my impatiens, which were overflowing their flat. I wanted to put them up (and untangle their roots) before they got too root bound and distressed. When possible, it’s best to avoid replanting already stressed plants, because the replanting process is stressful enough. Moving is stressful to humans. It’s no fun for plants either. But when all is said and done, they appreciate a new home with more room.


Step 1

Get yourself a decent potting soil that isn’t too heavy and will promote good drainage. I try to avoid anything with added fertilizer, since I’ll be adding my own. I like Miracle Gro Organic Choice–despite not being fond of their fertilizing products, this potting soil has a lot of organic material to promote good drainage. Your mileage may vary.

Step 2

I pre-moisten my potting soil. No little seedling wants to be roughly ripped from it’s nice, moist home and planted in bone dry potting mix, then drenched with water. Putting your seedlings into nice moist soil is the way to go. Here, I’ve dumped some potting mix into a stainless steel bowl.

Here a look at the potting mix and my ghetto setup. Yes, I’m using a printer box as a table. As I’ve mentioned, I’m cheap.

Here I’m adding some water to the mix. I like to use hot water–it gives the seedlings a nice warm place to move to.

I’m going to stir this up with a large stainless steel kitchen fork. (Anything will do for mixing up the soil, but the fork works really well for me. It’s like a miniature garden fork.) The goal is to make the soil moist and crumbly but not wet and gummy. You do not want mud.

(Note that the camera perspective makes the bowl look small and my hand look big. The bowl is actually fairly large. I can fill several 4 inch pots before I need to mix up more potting soil. But…you could do this in a large plastic storage bin just as easily and it would probably be much more convenient. I had no such bin on hand, so…steel bowl.)

Step 3

Fill up your pots with the moistened soil. You can go ahead and fill the pots right to the top as long as you don’t compact the soil. By now, your potting up room smells like spring and you’re longing for the great outdoors.

I’ve put my soil into 4″ plastic pots. These pots are either newly purchased or sterilized repurposed pots. They must be clean, because you don’t want to transfer fungus or other diseases to your healthy little seedlings. If you’re reusing last year’s pots (which I recommend, since I don’t like to waste resources), clean them thoroughly in a 10% bleach and water solution.

Now, make a hole for the seedlings. I use the big fork. I simply stick it into the middle of the mix, wiggle it back and forth a couple of times, and voila! —I have a nice hole, perfectly shaped, in which to plant my seedling.

Step 4

Now that my pot’s all prepped, into it the little seedling goes. I had to gently try to separate this crowded flat of impatiens by pulling the roots apart with a dinner fork. (I use a lot of forks, as you can see.)

Here’s a piece I separated out from the crowded flat. You want to be sure you’re getting as many roots as possible when you remove seedlings from a flat (this isn’t a problem with seedlings grown in individual cells, so I almost always use that method when I can, but no such luck with these impatiens.) I tend to work carefully, pulling the foliage apart and peering down at the soil to make sure I’m separating off a good sized piece that will have a sufficient root base.

The seedling fits neatly into the hole I’ve prepared with the fork.

And there’s baby in his new home. Isn’t he cute?


Since I moistened my soil before planting, I don’t usually worry about watering on day one after transplanting, but I do like to keep my seedlings in moist soil to avoid stress. I set the potted up seedlings in a tray and bottom water so they can wick up what they need. Note that you can always add more water to the tray if your first shot wasn’t enough, but that it’s a pain to move individually potted plants if you over-watered so that you can drain the tray. Don’t let your babies stand around with their feet in the water–this promotes fungal growth and rot, which can spell the death of an otherwise promising crop if newbies.

I keep my youngsters potted up indoors and under lights until the outside temperatures are warm enough for hardening off, and then out they go into the world to learn what it’s like to live in the great outdoors.


Entry filed under: Gardening Tips. Tags: , , , , , .

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4 Comments Add your own

  • 1. The Buxom Baker  |  March 25, 2011 at 4:44 am

    Your posts about seed starting have been so helpful! I’m starting my first seeds ever this year, just a few herbs, and your pictures and tips have been great. Thanks for posting them! My seedlings aren’t quite ready to pot yet but now I’ll know what to do :).

    • 2. petiolejunction  |  March 25, 2011 at 7:32 am

      Glad you found the information helpful! Good luck with your seed starting. For me, it makes waiting for spring weather almost bearable. πŸ™‚

  • 3. knoxee  |  May 7, 2013 at 10:34 am

    Great post for a plant noob such as myself! I’ve starting growing my first herbs, although I’ve realised I have far too many seedlings for the space in my apartment once I get to transferring them to bigger individual pots. (Is it ever OK to put multiple seedlings into one pot, or is that a bad idea?)

    • 4. petiolejunction  |  May 9, 2013 at 8:02 am

      Thanks for the kind comment, Knoxee. πŸ™‚

      In my experience, herbs will grow like weeds–fast and furious. It probably wouldn’t hurt to put more than one plant in a single pot as long as that pot was large enough (people do this with container gardens all the time), but be aware that most herbs grow quickly and you’re going to have to be sure you harvest often and keep an eye on them to make sure they’re not crowding each other out.

      Even so, you’ll probably never use all the seedlings your indoor seed starting adventures produce. I give the extras away to friends and family, or you could even list them on something like Craigslist or Freecycle and find homes for them that way. Gardening is all about sharing!


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