potting on | MissingHenryMitchell

How to Pot Up Seedlings That Have Grown Through Paper Towels

1. As before, prepare a seed flat with moistened, sterile seed-starting mixture. This flat, incidentally, is an upcycled Chinese food take-out container, and it is perfect for such a task.

2. Taking care not to cut off the root (which may have tiny root hairs emerging from it), guide the blade of the knife or scissors between the sprouted seeds. Cut a small section of towel to support the seedling:

3. Carefully cut individual seed mats out of the towel. Hold the towel up to a light to help you find the space between the roots.

4. Plant the seedlings, giving adequate space to each one. Don’t overcrowd the flat. Gently firm the roots against the soil.

The seed capsules on the soil surface fell off during the planting process. These are not additional, fresh seeds planted in the flat, which would overcrowd the plants.

5. Top the seedlings off with fresh seed-starting mix, up to the base of the seed leaves.

6. Water gently, using a rose on a watering can or the spray function of a faucet or squirt bottle, and set in a bright, warm space.

Keep an eye on the seedlings, in whatever form they were potted up, and do not allow them to dry out. Bottom-watering is best: Set the flat in a shallow dish of water and allow the water to wick up through the drainage holes in the bottom of the flat. Once the seedlings have developed one or two sets of true leaves, they may be potted up again.

I began the germination test on my hollyhock seeds on January 7. Yesterday, I opened up the bag to find ‘The Watchman’ ready for duty.

From your test, gently unfold the paper towel and see what’s happening. The photo above shows an excellent germination rate, and indicates the seed is still quite viable. In fact, of the 17 seeds I tested, 15 sprouted (88% germination rate, or 15/17). I’ve opened up towels to find the seeds exactly as I left them, which is depressing until you remember that that means you must purchase fresh seed.

What to do with them now? Keep them going. And here is a tip: They don’t care to grow on in paper towels. Pot them up!

Potting up bag-germinated seedlings

The seedlings at this stage have only their cotyledons, or seed leaves. Any handling of these seedlings must be done by grasping (gently!) the leaves, not the stem (more properly, the hypocotyl). And to slightly complicate matters, some of the roots have grown through the layer of paper towel.

1. Prepare a seed flat as you would if you were sowing fresh seed (which, clearly, you are). Use a clean container and fill it with sterile seed-starting mix. Moisten the mix and tamp it down well.

A clean seed pan filled with moistened, sterile seed-starting mix.

2. Grasp the seed leaves and pull slowly, firmly, but gently. Some of the seedlings may be just beginning to penetrate the paper towel, in which case you may be able to free them entirely. They’ll look a bit like bean sprouts you might find on a salad bar.

3. Make a slit or trench in the seed flat using a spoon or knife. Your finger will work just as well. Lay the seedling into the trench up to where the leaves fork from the stem.

4. Gently firm the soil back over the stem and root. Follow the same procedure for additional seedlings, but don’t overcrowd the flat. I’ve allowed six seedlings to a flat 3 inches wide by 6 inches long. None of the roots overlap.

5. Keep the flat warm (65-70 degrees) and well lit, either in a sunny windowsill or under a grow light. A fine dusting of sand, vermiculite, or even chicken grit can help to fend off damping-off.

In one more post, I’ll show you how to pot up those seedlings that refuse to release their security paper towel.