5 Signs It’s Time To Repot Your Seedlings
It’s important to be able to recognize when it’s time to transplant seedlings from the seed tray to a larger pot. Transplanting seedlings a few weeks after starting should be part of your seed starting routine.
We start the seeds in smaller containers because we can control moisture and temperature much better that way, and if you’ve heard me talk much about seed starting then you know my motto is that moisture and temperature are the most important factors in getting good germination.
But once the seeds sprout, they quickly outgrow their seed starting container. It would be a bad idea to let them continue to grow in a pot that is too small. They’ll become nutrient deprived and their roots will grow round and round into a big knot.
Transplanting them into larger pots, helps them develop healthier roots and grow faster. By not restraining their growth indoors, you’re training them to grow big and strong when it’s time to put them in the garden.
But how do you know when to repot seedlings?
There are a few simple things you can look for that are dead giveaways your plants need a bigger pot.
1. They have one or two sets of true leaves
The ideal time for transplanting your seedlings is about 3 weeks after they sprout or when you have 1-2 sets of true leaves. It’s better to get them in new containers before they start to show the signs of stress listed below.
2. The cotyledons are turning yellow and falling off
Cotyledons are the first leaves that emerge from a seed. They are different than the “true leaves.” True leaves are the second and subsequent sets of leaves that grow after the cotyledons emerge.
It is normal for cotyledons to yellow and fall off, but if they’re doing it when you only have 1 or 2 sets of leaves, your plants really need to be transplanted.
3. The true leaves are turning yellow
It’s definitely time to transplant if the true leaves are yellow. This is a sure sign that your plants are starved for nutrients.
4. The roots are wound around and around the root ball
You definitely want to see roots in your growing medium when it’s time to plant, but if they’re circling around the edges of the root ball, then they’re getting too crowded.
5. They’re crowded
You don’t want to overcrowd your plants when they’re young. Some plants will grow taller than others and that will affect how much light the others get. You’ll also get the larger plants sequestering all the nutrients and that will stunt the growth of your other plants as well.
Why transplant the seedlings at all?
You might wonder why we would go to the trouble of repotting seedlings at all? Why not just give them some fertilizer, or better yet, start them in a larger container to begin with?
You’ll be much more successful germinating seeds if you start them in small containers. This allows you to have more control over the temperature and moisture in the seed starting container. We’ve found we have much better sprout rates in the smaller cell trays as compared to using other types of seed starting containers.
You can dose your plants with some fertilizer but that will stimulate growth. They’re already telling you they need more space, why stress them by making them grow bigger in the same small space?
Both of those options are viable alternatives, but you’ll have healthier plants if you transplant instead.
How to repot seedlings
Transplanting seedlings is quite easy to do. You simply need a new container and some potting mix. We recommend a container that is twice as big as what they are in now and a high quality potting mix like Fox Farm Ocean Forest.
We like to mix the potting mix and the seed starting mix in a 50:50 ratio. This is especially helpful for young seedlings who still have tender roots.
Before filling your containers, wet down your soil mixture to ensure even watering after you plant. Then nest your seedling in the new container, filling in around the base of the plant and pressing down to seat it in well and remove air pockets.
For tomatoes, bury the stem leaving only 1 or 2 sets of leaves above the soil line. For all others, plant them level or bury the stem about 1/4 inch or less.
Water your transplanted seedlings well and place them back under the light.
What about fertilizing seedlings?
You can fertilize young seedlings after transplanting as needed. Use a liquid organic fertilizer diluted to half strength. If they tolerate the half strength and seem like they need more, you can up it to full strength.
Don’t fertilize your seedlings until after you transplant them. You don’t want to stimulate growth in a space that is too small.
Do you transplant or repot your seedlings?
Tell us about your experience in the comments below!
You've conquered seed starting. Woot! But do you know when to repot seedlings? Transplanting seedlings is a step you can't skip! Learn the signs your plants are telling you they've outgrown their seed starting tray.
When And How To Transplant Seedlings Into The Garden
Raising plants from seeds can be a rewarding and exciting way to add new varieties to your garden. Many of the best and most unusual varieties of vegetables are simply not available in your local nursery and your only option is growing these plants from seeds. But in order to grow these unusual varieties, you must know something about planting seedlings.
How to Transplant Seedlings
One common question from people who are growing plants from seeds is, “How do I know when my seedlings are big enough to put out in my garden?” This is a good question to ask when learning how to start plants from seeds because planting seedlings out in the garden at the proper time is crucial to their development later on. If you put them out before they are ready, they may have a hard time surviving the elements. If you wait too long, your seedling may become pot bound in its original container.
When it comes to how to transplant seedlings, there is no hard and fast rule to how tall a plant should be before you put it out in the garden, due to the fact that different plants grow to different sizes. Also, the amount of light a seedling gets can influence how quickly a plant grows in height when you are raising plants from seeds. If there is not enough light, a plant can grow very tall very quickly, but this plant may or not be ready for planting out. The best way to judge if a plant is large enough to plant out in the garden is to look at the number of true leaves.
True Leaves on a Seedling
The general rule of thumb is that when a seedling has three to four true leaves, it’s large enough to plant out in the garden (after it has been hardened off).
When you plant a seed, the first leaves to emerge are the cotyledons. These leaves will look different from leaves that will grow later. The purpose of these leaves is to provide stored food to the seedling for a short period of time.
True leaves grow shortly after the cotyledons. The true leave emerge and start generating energy through photosynthesis that will help feed the plant for the rest of its life. Making sure that the plant has enough of these leaves to keep it sustained when planted out in your garden is important to its proper growth.
Just remember, it isn’t how tall but how many true leaves your plant has that will determine when you should be planting seedlings out. But even when your seeds are big enough to plant out, make sure you harden off your seedlings before planting them. When growing plants from seeds, you want them to be plenty prepared to grow into beautiful plants that will provide you with a bounty of delicious vegetables.
One common question from people growing plants from seeds is "how do I know when my seedlings are big enough to put out in my garden?" This is a good question to ask, and this article will help.