Welcome to today’s blog, which focuses on maintaining seedlings during the process of starting seeds indoors. Hopefully you had a chance to see our previous blog on successfully germinating seeds indoors. It will give you insight on the first steps to take when deciding to start seeds indoors. Today we’ll assume (or pretend) that you read it, have begun germinating your seeds, and now need to move on to the seedling maintenance tips. Let’s jump right in!

Seedlings sprout fast when given moisture and warmth.
seedlings can be grown in many types of containers.

5 Steps for Maintaining Indoor Seedlings

1. After Germination, Remove Plastic Wrap from Seedlings

Congratulations! You’ve checked on your seed pots and you found your seed bursting open and a teeny, tiny plant is starting to unfurl. Hooray! You are now the proud parent of your very own seedling.

First step is to remove the plastic wrap you had on your pot to keep your seed warm. Once your seeds have germinated, the plastic is no longer needed to hold in humidity and moisture. Your newly sprouted seedling will need good air circulation and light.

With the plastic wrap off, you will need to be aware that moisture will be released as well as heat. Keep your seedlings in a warm area and make sure to check them everyday to see if they need water. Water gently when the soil is dry to the touch.

2. Provide a Light Source for Seedlings

Now that your seedlings have reached out from their inner seed casing and poked up and out of the dark soil they will naturally be looking for light. The seedlings will be craving and searching for the sun, so if you can’t offer them enough natural sunlight from a window in a protected area of your home, you may have to think about investing in some grow lights.

If you can offer a substantial amount of natural sunlight for your seedlings, coming from a south-facing window, go for it! Sunlight: It’s warm, it’s free; it’s full of Vitamin D! The sun provides energy to the seedlings for healthy growth and development. You’ll just need to make sure you are turning your pots around often so that all your seedlings receive equal amounts of sun exposure. Light from a window is somewhat one-sided.

(If your seedlings begin to look like they are really stretching out and getting lanky-looking, it might be a sign that they aren’t getting enough light. You are trying to grow fuller, more vegetative transplants from your seedlings, not weak, spindly, wispy transplants.)

If the windows won’t do the trick, there are plenty of grow lights available to mimic the sun’s rays. Grow lights can offer seedlings a light source any day, anytime of the year. Have a week of cloudy days? No problem, if you have a grow light. Grow lights can offer an overhead light source so that all your seedlings get even exposure. Grow lights can also offer an extra source of warmth for your young seedlings.

3. Moisture for Seedlings

You never want your seedlings to dry out, but too much water in the soil can be the kiss of death! You’ll have to find a middle ground and keep your seedlings happy in a soil medium that is consistently moist, and in other words, just right! If the soil medium dries out completely, it might never recover enough to provide any moisture to seedling and the roots shrivel up and die. If your soil stays too wet, the roots of the seedling basically soak in a bath until they become slimy, rotted and then die. Death is the common factor in these scenarios. Avoid it. Water sparingly while you have seedlings.

4. Thinning your Seedlings

Remember those three seeds we told you to plant in our previous blog? Here’s why. Take a look at the seedlings in your pot. Is there one seedling that looks a bit more attractive than the others? It’s okay if the answer is yes; “survival of the fittest” is coming into play. If you thin out the weakest links, you are leaving the strongest seedling plenty of root room to continue it’s healthy development. If you leave the three seedlings in the pot to develop into transplants, they will compete with each other and you may end up with three weak and compromised transplants and none of them are that great of a candidate to be planted in your garden.

When your seedlings develop their first true set of leaves, not the first or two little mouse-ear shaped cotyledons that develop right after the seed germinates but the true leaflet set of leaves, it’s time to thin your seedlings. True leaves have the appearance that all future leaves on the seedling will have, and they probably look very different than the first leaf or two that you see. (See pics below for examples of the 1st and second set of leaves.)

Take a pair of scissors and cut the weakest seedlings off at the soil line. Don’t try to pull the seedlings out as this could disturb and damage the roots of the strong seedling left behind.

Thin seedlings when they have developed their first set of leaves.
Seedlings have developed their first true leaves and are ready to be thinned.

5. Hardening off Seedlings

Once you’ve thinned your seedlings and your plant is continuing to grow new leaves, it’s time to either transplant your seedlings into a larger container or think about “hardening them off” for planting in the garden, if the timing is right. (Early tomatoes get bumped up to larger containers to grow while being protected until danger of frost has passed.)

“Hardening off” seedlings is a process where you gradually adapt your seedlings to the environment they will be exposed to in your garden.

Once the danger of frost has passed, set your seedlings outside, in a shady area for a few hours a day and bring them back in at night. You can do this for about 4-7 days. The following week, incrementally offer more exposure to sunlight so that by the end of two weeks, your seedlings are ready to be outside all day and night, and ready to be transplanted in your garden.

Extra tip: When you move your seedlings outside, keep an eye out for slugs and snails which love to munch on young, tender shoots of new plants.

That’s basically the gist of seedling maintenance before the plants head into your garden. Hopefully you’ve prepped your garden soil and it is ready to welcome these new plant babies with open arms.

Are you ready for the next step? Keeping those young, tender, plants growing so your seed starting endeavors won’t have been in vain? Head on over to our next blog which is all about successfully getting your indoor transplants to the outdoor garden. See you there!

~The Happy Gardener, Lisa Mulroy