As promised, I’m back today with with a more detailed post on containers for seed starting!
The great thing about seed starting containers is you have a lot of options, each with their own advantages and disadvantages. Determining which one is right for you comes down to your personal preferences as a gardener: What’s your budget? How much time do you want to spend preparing? Do you prefer to do it yourself, or do you want to open a package and go? What’s your level of concern about environmental impact and sustainability? How much storage space do you have for the off season? And we haven’t even stopped to think about what you plan to start from seed yet!
To help you navigate through the many options, I’ve put together the following guide to seed starting containers. As you work your way through the list, evaluating the advantages and disadvantages, you’re sure to find at least one option that feels right and works well for you.
Plastic Cells + Pots
These familiar plant cells and small starter pots are readily available for purchase, reuse from previous greenhouse purchases, or even for free from the recycling pile at some garden centers. Plastic pots can be found in a wide variety of shapes and sizes, but the individual cells are a standard size designed to easily fill an entire starting tray. These containers are designed for good drainage and have good depth for root development, though the smaller cells may require some up-potting to prevent the seedlings from becoming root bound. It is not the best choice if you are concerned about plastic consumption, though plastic pots can be sterilized and reused for multiple seasons, and recycling options for cracked and broken pots are becoming more readily available.
Peat, Coir, or Manure Pots
This option is also available in the form of individual pots in various sizes, as well as packs of multiple cells. The cost for these pots is about the same to slightly more than what you would pay for their plastic counterparts, depending on the material. Because they are designed to breakdown within the course of a year, they do not hold up for repeated use. These containers are easy to use; they are package-ready, so there’s no preparation necessary outside of filling them with starting medium, and they can be planted directly into the ground at the time of transplant.
Coir or Peat Pellets
These little pellets are composed of compressed coir dust or peat, contained by a fine mesh or paper-like casing that hold it all together. When water is added, they expand to about three or four times the height of the dry disk and reveal a convenient little hole to pop your seed into. They are a little fussy to prepare, but you do get a container and starting medium all in one. These pellets are also a one-time investment, and tend to be more expensive than other plantable pots. They are not particularly effective for seeds that prefer to be surface sown, and the small size almost ensures that up-potting will be necessary if seedlings are growing for more than a few weeks.
Reusable Plastic Containers
From yogurt containers to solo cups, there is quite a bit of seed starting potential already in your recycling bin. Find containers of a suitable size, clean them up, and add drainage holes with a drill or a hammer and nail. Because seed starting containers are exposed to a lot of water, light, and heat, it’s a good idea to note the recycling number on the bottom of the container. Numbers 3, 6, and 7 should be avoided; 1, 2, 4, and 5 are safer options. These plastic pots provide the good depth and width for root development, and could be washed and reused for multiple seasons. If you are using a mixture of different kinds of containers, it is a good idea to make them as uniform in height as possible, to make it easier to position the light at the appropriate distance above the seedlings.
Clam Shell and Lidded Containers
Again, this is another great reuse of something that would otherwise end up in the waste stream. The lids can double as a germination cover, and they usually already have holes for good drainage. The lids also make these containers a great option for winter sowing (more on that to come!).
Raise your hand if you started an egg carton garden at some point during your elementary school years! The individual cells are convenient and easy to fill, and the paper material is very efficient at wicking up water from the bottom of the tray (almost too efficient at times; when there isn’t enough water in the bottom tray, they can wick the moisture from your starting medium, so keep a close eye on that). Because they have a lower profile, they also do really well on a heat mat. The obvious disadvantage is that the cells are very small and not very deep, so you will need to up-pot your seedlings after a few weeks.
While they might look super cute on Pinterest, that’s about all these little guys have going for them. In order to get much in the way of depth, you have to be a pretty stealthy egg-cracker. Even if you can remember that you need to crack off only the very top of the egg before it’s too late (don’t ask how many mornings of breakfast it took to get just these three eggs because it wasn’t my first instinct to crack the eggs that way), it’s just simply not worth the time. You will not end up with any more space than you would with the egg carton itself, which is a thousand times easier. Watering and drainage are also difficult, and despite Pinterest claims that that you can simply plant the entire thing in the garden (has that person actually ever planted a garden?), there is virtually no way that a tender seedling is going to develop the roots necessary to bust through that egg shell in the short time it will take to outgrow it. Your egg shells are better off in your compost pile or crushed in the bottom of the holes for your tomato transplants.
Toilet Paper + Paper Towel Tubes
If you’re looking for a much more practical Pinterest project, you can make starter pots out of the cardboard tubes inside a roll of toilet paper or paper towels (Minnesota Locavore has a great tutorial). While you can’t do much to adjust the width of these starter pots, you can opt to make them a little taller, which will give you a little more space for root development and buy a little time before up-potting is necessary. The cardboard does soften easily, but it doesn’t really breakdown enough to plant the entire thing without opening up the bottom of the pot or tearing into the sides a bit at the time of transplant to give the roots more room to spread out. Depending on the number of seeds you are starting and your household consumption of these products, you may need to plan ahead and start saving early to have what you need by seed starting time.
I’m going to go right out and say it: newspaper starter pots are my all-time favorite, personal go-to seed starting container. They are super easy to make and they can be made in any size you need. One Sunday paper has more newspaper than you will likely need for an entire season, and you probably have several suitable items in your home that can be used as a mold to shape the pots. The drawbacks are that the pots can become a little fragile as time goes on and the paper fibers start to break down (this can be especially true if you make very large newspaper pots as well), and on the other hand, if there are too many layers of newspaper, the paper won’t break down as easily or as quickly, and you may need to peel it off prior to transplanting.
Paper Pulp Pots
I experimented with these starter pots last year, thinking they would be a great option for a truly plantable starter pot. They are easy to make, but they are a little more time intensive and can also take up to a few days to completely dry. The muffin pan size has a lot of width, but not a lot of depth. I did have success in making deeper pots using a plastic wine glass as a form, but they were not as sturdy once they were filled and re-wet. For that same reason, they really are a much better option for a truly plantable starter pot and would be especially good for squash or cucumbers, which aren’t started that far in advance and do not like to have their roots disturbed. It’s also a good place to point out that just as not all plastic is safe for reuse, you may also want to look into what adhesives, inks, bleach, etc. is used in the paper products you use for seed starting.
If you’re looking to use as few materials as possible in seed starting, consider soil blocks as an alternative to seed starting pots and containers. Soil blockers are available commercially in several different sizes, or you can make your own with a few inexpensive pieces from your local hardware store (I made a simple one for about $2). While it may seem counterintuitive to saturate and then compact your starting medium, if it is composed of the right materials, your roots should still do well. These little plugs can then be transplanted into a larger container after the seedlings have a set of true leaves or outgrow the soil block, whichever comes first. You do need to watch your watering, as the only drainage provided is whatever indents might be in your drip tray.
Now that you’ve heard from me, add your voice to the discussion: Cast your vote by sharing your go-to container for seed starting. How have some of these options worked for you? What factor(s) drive your choice in a seed starting container?