If you’re like me and sow multiple seeds, eventually your little seedlings will run out of room in that initial cell or container. When that happens, you’ll need to move your seedling to a larger container so that it can keep growing. Read on to find out more about why you should pot up and how to do it.
Why pot up?
Potting up really depends on several factors, but ultimately you pot up to promote healthy, vigorous plants. If kept in those initial cells that you started with, the roots will eventually outgrow that space and become what we call root-bound. When this happens the roots begin to circle around themselves and become a tangled mess.
The stress that being root-bound places on the plant can cause stunted growth and when you are finally able to plant it out in the garden, a root bound plant might not be able to spread its roots and continue to grow.
How do you know it’s time to pot up?
There really isn’t any sort of rule for when you should repot seedlings and it’s up to each gardener to determine what works best for them. Here is what I look for:
- At least one set of true leaves. When seeds first emerge they have what’s known as a cotyledon leaves. After a few weeks, you’ll see new growth and that will be your true leaves. Once the true leaves have emerged, the cotyledon leaves will start to yellow and will likely fall off. I like to make sure I have at least one set of true leaves, preferably two, before I pot up.
- Roots have started poking out of the bottom. If you gently look on the bottom of your seed starting container, you may see some of the roots peeking through the bottom. This is not always an indication that it is root bound but it is a sign that it will need more room soon.
- Seedlings dry out quickly. This is not always a sign that your seedlings are ready to move up, but if I notice that they are drying out faster, meaning the plant is using more moisture, then I start making plans to move it up.
How to pot up your seedlings:
Now that you have determined that your ready to pot up, here is what you’ll need to get started:
- Potting soil. This is different than the seed starting mix you initially used. Potting soil will typically be a little bit more dense and might have some added fertilizers to promote growth. There are many options out there but I like to use Pro-Mix All Purpose, Fox Farms Ocean Forest, or Sunshine Mix and mix that with whatever leftover seed starting mix I have. Typically, it ends up being about 50/50. Some potting soil will be very dry when you take it out of the bag. Just lightly moisten it before you get started.
- Containers. There are a few different ways to approach container selection and it’s going to be contingent on what you’re growing and how far away you might be from your planing out date (the day you plant your seedlings outside). Ultimately I look at plant size as determine if the seedling can go in a larger cell-type container like this:
If the seedling is not particularly large, I’ll likely go with one of these cell type containers. If the plant has several true leaves, a sturdy stem, and a robust root system, I will choose a larger pot like this:
Step – by – step
- Prepare your containers by filling with potting soil. Leave a little bit of space on top.
2. Carefully remove seedlings from the germination cell. I usually hold the bottom and loosen the roots by giving the cell a little squeeze.
3. Begin separating the seedlings by gently teasing the roots apart. You’ll probably loose some roots in the process but it will be fine.
4. Once you have your seedlings separated, grab the pot you would like to use and make a hole that is deep enough for the roots plus some of the stem.
5. Carefully place the seedling into the hole and fill in around the plant. For peppers and tomatoes, I bury the stem up to the cotyledon leaves since any part of the stem that is buried will root.
6. Make sure to label your plant and gently water. Place them back under your grow lights and continue to care for them until it is time to harden them off outside. When you first repot your seedlings, you might notice that growth is a little bit slow. This is happening because the roots need to reestablish themselves and get comfy before it can put out new growth on top. This is normal and it might be a week or so before you see much going on.
