Most seeds can be started in two-inch pots or similar sized flat cells, and then repotted up to a four-inch size if needed before transplanting into the garden.
DIY Options
If you are taking a frugal or ecologically minded approach to gardening, you may be wondering if you can use DIY pots.
Some gardeners repurpose egg cartons, toilet paper rolls, paper or plastic cups, or nearly any other shallow vessel that will hold growing medium.
I tried the DIY egg carton and toilet paper roll methods years ago, and while this creative reuse scores points for the environment, these aren’t my favorite starter container options.
Cardboard egg cartons may work for smaller starts, but most annuals will outgrow their shallow cells very quickly.
And the year I tried using toilet paper rolls as seed cups, they started falling apart well before the seedlings were ready to transplant.
I can’t really give a hearty recommendation to either of these options.
I have successfully used paper cups as a DIY-biodegradable option, but since learning these contain a plastic coating, I won’t be going with this method again as I’m trying to keep microplastics out of my garden soil.
You can get creative and find other containers to start your seeds, but if you want to hedge your bets, your best option may be to purchase containers intended for this purpose.
Biodegradable Pots and Trays
You may also want to consider commercially made biodegradable trays or pots.
Seedlings grown in these can be planted, container and all, directly into your garden soil, raised bed, or even into a larger container, without disturbing the delicate roots of your seedlings.
As far as biodegradable options go, I highly recommend CowPots, a more environmentally friendly option than those made from peat moss.
CowPots are made from composted cow manure sourced from a Vermont dairy farm.
Not only do they have a light environmental footprint since they reuse waste material, but after transplanting, they will nourish your plants as they break down.
CowPots #3 Six Cell Flat
You can find six-celled CowPots flats in packs of various quantities at Arbico Organics. Each cell in the flat is approximately three inches square by three inches deep.
These flats can also be cut into individual containers!
And just like the biodegradable seed flats mentioned above, CowPots are also available in larger sizes for repotting.
CowPots #5 Square
You can find square CowPots sized at 5.25 by 3.5 by 5 inches in packs of 60 or 192 at Arbico Organics.
In my arid climate, these biodegradable types are a little tricky to manage as they have a tendency to dry out very quickly.
