When I first started my plant starts from seed, I needed some kind of container. I had yet to hear about soil blocking, so that wasn’t an option. And the flimsy containers at my local garden store didn’t seem like a great option either as I want to have a container that could be used multiple years in a row. Then, the simple solo cup was born as a seed starting container.
The world of seed starting containers
I’ve done my fair share of research on what’s the best way to start seeds. With that comes the best container to start you plants in. There are heavy duty pots, flimsy disposable pots, biodegradable peat pots, multiple cell flats, and even no pots at all (a method called soil blocking). There are so many options! And here I am, still hanging on to my reliable solo cup for starting my plants in. Why, you might ask? I definitely have my reasons. Let’s first look at a few of the many options along with their pros and cons.
Disposable plastic pots
These are, by far, the most common containers used to start seeds. Greenhouses use them all the time as they are cheap and yet reliable enough for customers to take their starts home without completely getting soil all over the place. Plus, it’s what the people expect. They also come in a variety of sizes, shapes, and colors which makes them even more appealing. These can be good to use because if you take care of them, you can re-use them for one or two years. However, if you are only starting seeds for your garden rather than selling, they can be a more expensive option compared to others. Also, because they are cheaply made and less durable, they are more likely to crack, rip, or break.
Heavy duty seed starting containers
When I say heavy duty, I mean heavy duty. Many greenhouses don’t use heavy duty plastic containers as they are more expensive and relative to the disposable ones, it really only costs them more without providing any extra value to the customer. However, home gardeners who start their own seeds would see the value in that the one purchase would last them many, many years. The containers fit well in trays and also come in many different sizes. Basically, they’re the nice Tupperware of the plant start world. These are likely the best quality, however their caveat is that they come with a large upfront cost.
Biodegradable peat pots
These pots are made of a material called peat which is often harvested from bogs. It’s soil like and degrades in nature, however there is only so much of it available. These are a one-time use, come in various sizes, and are relatively expensive. I have tried these in the past but have never had good luck. I believe this is for two reasons. One, they are difficult to water. The peat hold on to moisture and can cause molding which can in turn kill your plant starts. Second, while you are supposed to be able to plant the pot directly in the soil I feel as though it restricts the roots of the plant and hinders it’s overall growth.
Soil blocking essentially has no container at all for the starts. Instead, you press damp soil into a metal mold to form soil “blocks” which you then place in your trays to start your seeds in. There are different sized molds that you can choose to purchase depending on what you prefer to plant. From a cost perspective, you only have to buy just one mold to form hundreds and hundreds of blocks. There is an upfront cost, but then essentially you would never need to buy containers again. The downfall is that watering soil blocks is a little trickier than just dumping water into a tray. You need to be fairly careful or your soil blocks will just become soup.
Solo cups have a few unique factors that make them suitable for starting plants in. One, they’re fairly durable. They can crack or break, but usually they’re pretty reliable. This also makes them good candidates for being re-used. Two, They’re cheap. You can get hundreds of solo cups for literally a few dollars. Three, they hold a good amount of soil. Comparatively, solo cups are similar to a five-inch plant pot. They hold a lot of soil. However, a five-inch plant container is definitely going to cost you more than a solo cup. Why would holding more soil even be desirable? The more soil the container holds, the more room there is for root systems to develop. This allows the plants to grow a considerable amount without becoming stunted.
Reusing Seed Starting Containers
Let’s be real, reusing your containers year to year is cost effective and helps the environment by you as an individual “consuming” less. As I’ve pointed out, I reuse my solo cups each year. There is a step you need to take each year to ensure healthy plants when reusing containers.
Wash & Disinfect
This may sound obvious, but it’s a step that can easily be forgotten. When you re-use your containers each year, last years potting soil along with any bacteria, mold, or plant viruses can remain on the surface. If you fail to clean and remove these, you can be setting up your newly started plants to fail.
Take the extra steps and wash each container with soapy water first. This will remove any large particles like the potting soil or moldy residue. I tend to just do this in my sink (after which I wash my sink out really well), however if you prefer you can use a tote outside in your garage. The key is to use hot water.
Follow with making a solution of hot water and bleach. It doesn’t take much, I tend to just rinse out my sink, re-fill it with hot water, and add a dash of bleach. Submerge each container for at least 30 seconds to a minute, rinse with hot water, and set to dry.
If you’re using solo cups that are on the more durable side, you can also choose to just rinse the potting soil out and place in the top rack of your dishwasher to wash and disinfect. Full disclaimer, if I had this option I would choose it every time. Currently, I am without a dishwasher though, so hand washing and bleach it is!
The preferred choice
So, while many options exist I still continue to use my standard solo cups to start my plant seeds every spring. They hold a good amount of soil for literally pennies. They can be re-used year after year as long as you wash and disinfect them to get rid of any un-desirable “bugs”. And they’re durable and super easy to use. Those are the three main reasons. Every other option has at least one of the qualities, but never all three. Plus, it doesn’t hurt that they’re easy to acquire as well!
I’m not saying that I’ll never invest in some super durable plant start containers. In fact, some day I’d love to make the investment. However, I have no need to. If I do, it will be from a place of frivolity, not one focused on cost effectiveness. If you are focused on cost effectiveness, durability, and growth potential for your plants, the standard solo cup is a fantastic route!
So go out, buy yourselves some solo cups, add a couple drainage holes to the bottom, and lets start some seeds!