So, the hard part is over, right? Getting seeds to germinate and keeping them alive long enough to admire them is a rush… but now what to do? They’re going to keep getting bigger, and we know that the small pots they’re in aren’t going to do the trick forever.
If you live in the northeast like us, it’s a very real possibility to see snow in the middle/end of April, so we won’t be doing any planting outside until mid-May. The best way to help your growing seedlings is to transplant them into bigger pots, as well as begin to feed them small amounts of fertilizer.
A quick way to determine if your seedlings are ready for transplant and feeding is to count the number of leaves. Seedlings sprout one set of leaves after bursting up through the soil, but they’ll also sprout a second set of leaves shortly after. These are their first sets of ‘true leaves’.
By the time you have 2-3 sets of true leaves, your seedlings are strong enough for a move to a bigger pot, and ready for a bit of added nutrients now that they’ve taken all they can from the seed starting mix.
We asked Jaci, the Head of Research and Development, for her best advice on transplanting seedlings:
What Seedlings to Transplant & When to Transplant
Jaci: For the most part, you’re starting things indoors to give them a head start before they go outside. Sometimes things need to be started so far in advance that they outgrow the pot you started them in… hence transplanting.
If you’re starting your seeds in seedling flats, you’ll want to transplant your seedlings into 3″-4″ peat, cow pots or an up-cycled container.
The longer amount of time that the seedling will be in it’s ‘final pot’ (the last container before being transplanted into the ground), the bigger pot you’ll need. The general rule of thumb is that you disturb the roots of your seedlings as little as possible.
What Type of Soil Should You Use for Transplanting Seedlings?
J: I suggest transplanting into a potting mix that contains more nutrients. You can also mix in worm castings as a supplement; this is something I do with my own transplants.
What Seeds Do I Not Transplant?
J: Some plants have such delicate root systems that they can’t really be transplanted into another container, like radishes, parsnips, or carrots. These things need to be sown directly into the soil.
What's the Best Fertilizer for Seedlings?
J: By the third set of ‘true leaves’, you’ll want to start feeding your seedlings with a greatly diluted fertilizer. I use a 1/4 dilution of suggested measurement to start off. You don’t want to burn the seedlings, so be careful how much you use. I suggest using fish emulsion or kelp fertilizer. You should fertilize about once a week with the diluted mixture. Keep an eye on your seedlings to make sure they stay green and healthy. If they start to change color or look unhappy, they may be missing a key nutrient.
We re-homed some of our own seeds this week:
Little Bing Tomatoes, Baby Blue Eucalyptus and Multi-bloom Mix Geraniums.
We used our Vermont Compost Company Fort Light Compost-Based Potting Soil as a base and gave it a good healthy drink before filling up our peat pots.
Next, we gently loosened the soil around our strongest seedlings to prepare for a move. If your seedlings are particularly delicate or small, a widger will help a lot.
Jaci, very carefully separated the Geranium seedlings. This thinning process allows the plants more room to grow.
Working with a pre-moistened soil makes it easier to ensure the fragile roots have an easier transition.
Once your seedlings are in their new pots, give them another small drink of water to help their roots establish in their new homes. Give them plenty of light, regular watering, and keep an eye on their growth! It won't be long before they're ready for the full garden.
Got questions? Give us a call or send us an email. We're here to help and are committed to helping every home gardener suc-seed🌱
Damping off is a disease and is spread in containers or soil that isn’t sterile. Clean your pots or flats before use and give them a bleach soak and then use seed starting mix – it is not soil and doesn’t contain the soil microorganisms that can cause damping off. Use potting soil to transplant once the second set of leaves is present and healthy. Damping off isn’t as much of a threat then.
I have been starting seedlings indoors for 53 years. 1) First thing I learned is if you bought one of those seed started kits with a clear plastic top to keep the flat moist – do not use that cover, ever, you will loose the seedlings to damping off disease. Just water the flats every other day. 2) Do not put the sprouting seeds in a south facing window. The sun’s heat will make the plants grow too fast and they will be weak and libel to damping off. 3) If you use peat type pots they must be inside of some kind of container to keep the pots from drying out. ( I use my wife’s old cake pans). 4) For light I use florescent lights about 4 inches above the plants. 5) Side by side trials of different growth mediums showed no difference between mid range starter, top of line seed starter, and my back yard compost. The cheep stuff that looks like shredded wood is really bad. All I use is my compost.
Very helpful information. Thanks !!!!
Good advice. Also to mention, handle the transplants by their leaves, not the stems. The plant can make new leaves, but if you break the stem, you have killed the plant.
Been doing this for years and the “little green seedlings” are so uplifting as spring approaches! I ALWAYS “bite off more than I can chew”, i.e., not enough space for transplants on windowsills etc.and am usually very pleased with the healthy seedlings I end up with! Handling the transplanting of the little ones is essential and thanks for the advice on diluted fertilizer which I knew but sometimes get over zealous! I HATE damping off disease!!! It’s the worst!! I actually keep my house at a warmer temperature during seeding time to avoid this, but it still happens and is heart wrenching watching them fall and rot!