Four Different Seed Starting Methods

If you’ve found me via the rabbit hole of seed starting, welcome! A cursory internet search will turn up an overwhelming amount of advice, and I’m glad you’re here to check out mine. Through all my research and personal experience I’ve come up with the four most popular methods of seed starting and I want to share some information about all of them in one place (spoiler: I use all four!). If you’re not sure where to begin or you’re not super happy with the method you’ve been using this is the post for you. I list my pro’s and con’s for each type of container as well as shopping recommendations!

Plastic Cups

AffordableCan be out of stock due to supply issues
Easy to labelMay start to decompose if not treated properly
Semi-ReusableNot environmentally friendly
Locally AvailableRequires modification for drainage holes
Plastic Cup Pros & Cons
Cup Seedlings

This is the route many people take when they’re first beginning to start seeds at home, and for many it’s an enduring solution! I still prefer to pot up my tomatoes into plastic cups because they’re easy to store, they’re reusable, and they’re usually easy to find – I say usually because since the pandemic hit there has been a shortage of the particular type of clear Solo cups that I like to use, and while generic brand plastic cups work perfectly fine, my experience is that they really are only viable for one year of use. This is neither practical nor sustainable, so I prefer to buy name brand and they’ve occasionally been hard to come by the past two seasons. That being said I still have cups that I’ve been reusing since my first season nearly 4 years ago, so that tells you how long they can last when properly cared for! Even though they’re recyclable, these are probably the least environmentally-friendly option on the list if that’s important to you personally.

Plastic cups are a really attractive option for those who don’t want to continue to pot up their seedlings as they get larger, meaning they’ll experience less shock as a result of repeated transplanting. Some of the latter options I list here require potting up and like I mentioned earlier, I still prefer to pot my tomato plants into plastic cups after about 4 weeks because I can bury the stems as far as I want when I do so.

Now, are colored or clear cups better? Some people say that using clear plastic isn’t good for root health because of light exposure, but I have noticed absolutely no difference in root development using the classic red vs. clear Solo cups. I like to use the clear green plastic cups to provide a little opaqueness but still enough clarity to keep an eye on the roots. Having a window into the condition of your seedlings beneath the surface is a wonderful tool. Whichever you decide to use you can rest assured that they will all provide the same results. Just be sure to drill a hole in the bottom to ensure proper drainage!

You can also write directly on them using a permanent marker, which makes labeling your plant starts super easy. Any seedlings that I sell or give away make the journey to their new homes in plastic cups just for this reason – no tags to fuss around with or get lost in transit!

Plug Trays

ReusableRequires potting up
Available online and sometimes in storesCan be difficult to label
Easy to useMid-level startup cost depending on brand
Many types to choose from
Plug Tray Pros & Cons
Plug Seedlings

When it comes to plug trays there are many different options to choose from. Products vary in material, plug size, tray size, and usage. I haven’t personally bought many plug trays because I have limited use for them, but I can attest to the quality and functionality of Burpee’s Super Seed Starting System. I stocked up on these thinking that I would use them for all my starts but I ran into a potting-up problem early on since I have to start seeds so far in advance in my cold climate. However, I still use them for starts that are indoors for a relatively short amount of time and I love them for what they are. The silicone bottoms made for easy pricking out, and the bottom trays are pretty sturdy. They’re a mid-range option in cost and since Burpee is a large company they have superior customer support if any issues may arise, like a cracked tray or handle. This didn’t happen to me but my mom experienced it twice in one shipment of this product.

A brand that is highly recommended across the board is Bootstrap Farmer. They have a line of durable, quality seed starting materials in many different configurations and even colors to choose from. I am the proud owner of a few precious flats from their old-style products, and I can tell you with great conviction they’re made to last!

Open Flats

AffordableRequires potting up
Locally availableCan be difficult to label
Many types to choose fromNot suitable for all seed needs
Good option for multisowingCan’t bottom water some types
Reusable, depending on type
Open Flat Pros & Cons
Flat Seedlings

Another option for seed starting is simply a shallow, open container which you fill with soil and then plant with seed. This can be a designated gardening product or something you can repurpose of the same shape and size. The possibilities are almost endless for this type of planting, and I’ve seen gardeners use foil pans, Tupperware containers, or even takeout boxes for this method. I start my onion bulbs in flats and I prefer to use cake pans which I sourced from the Dollar Tree (score!).

One of the things I dislike about this method of seed starting is if you’re not using a specialized seed starting product, most of these containers must be modified for drainage. If you use this type of container be mindful of overwatering and be sure not to let them dry out either.

Plants that are more sensitive to transplanting like cucumbers and squash shouldn’t be planted in open flats since they usually require potting up. However, flats can be a wonderful solution for gardeners that multi-sow and prick their seedlings out directly into the garden plot.

Soil Blocks

Infinitely reusableHigh startup cost
Reduced plastic wasteCan be difficult to label
Many types to choose fromNot suitable for all seed needs
Good option for multisowingTakes time to learn technique
One-time investment
Soil Block Pros & Cons
Soil Blocks

I’ll just say up front that soil blocks are my favorite way to start seeds! I own the entire series of Ladbrooke blockers from the micro to the large size, although I have yet to use the latter. The system I’ve devised uses cookie sheets (again, Dollar Tree or Walmart special, so very affordable) to stamp out my soil blocks onto, and I attach miniature binder clips with tape labels to indicate each row and what type of seeds it contains. Soil blocks boast many health benefits for your seedlings, including the natural pruning of the roots as soon as they hit the air – so no bound-up roots or soggy rot to be dealt with.

However, soil blockers can take some trial and error before you’ll become really skillful when using them. They require a very particular type of soil mixture in order to work, and getting the dampness of the growing medium just right is what will make or literally break your blocks. Too wet, and they won’t shape well. Too dry and they’ll crumble apart. So achieving the proper seed starting mix and moisture ratio is very important to using these tools effectively. There are many videos out there on mixes and moisture levels and I encourage you to do lots of research and not to get discouraged. It took me a few times to get the hang of them, but since I have I’m enamored of them! I’ve never had better results with my seedlings and they eliminate the need for plastic waste.

While there are plenty more seed starting methods out there I’m sure we’ve covered the most popular in this post. Please share in the comments your favorite tips for seed starting!

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