I just ordered some more - I loved that as well. I am growing every single tomato variety from Seeds Trust along with a pile of others. It's over 100 varieties now - ridiculous. It is my hope to sell tomato plants at the Farmer's Market again this year. Many friends will attend.
On Valentine's Day we plant tomatoes - it's great fun - we really look forward to it. It makes it "Tomato Day". This triggers a snowball effect of flats growing all over the place. How do I plant so many varieties and keep it all straight? Pretty easy stuff.
I use wooden flats - with slats on the bottom, lined with newspaper, filled 3/4 full with decomposed pine needles, then covered with an inch or more of a coir based seed starting mix. They become nice and spongey and barely leak.
To keep the varieties apart I use craft sticks - popsicle sticks - to label them and to separate them. It's easy and cheap - you can get a huge box of craft sticks for very little.
If I do not somehow physically separate the tomato varieties there will be confusion and mix ups. When you grow so many varieties this is a huge issue, from seeding, to transplanting, to labeling and selling - you need to know who's who.
The other option is to plant another plant between them - but something that likes to germinate at 75 degrees, like tomatoes, which could include peppers, eggplants or basil.
Since I love to use my open flats and since I learned a ton from my friends at a nursery I used to work at, I learned I could crowd the heck out of the flats. At the baby stage, they don't need much and quite possibly in nature, germinate clustered from the fallen tomato. So I can dump the seed quite closely - because I'm going to prick them out with another craft stick and pull them apart by the leaves and pop them into their individual pots where they can do their thing.
They are only going to be in the seedling flat for a short time - so they can wait for the yummy potting soil they are going to get next to grow on with.
After I carefully sow and label as many as I can squeeze in, it's time to cover the seeds lightly with the soil-less mix I use which is almost always coir based. (Coconut fiber.)
It doesn't matter if the horizontal craft sticks - the barriers, get buried a little - it all works out later when I am pulling plants out of there. It is clear who is on what side of the stick.
Seed to soil contact is imperative for better germination so I lightly press it down with my hand gently but firmly. After that I use a fine rose spray to water with so as not to wash the seeds away. This is why we start with pre-wetted, moist mediums.
The last step is to cover the moistened flat with some plastic or glass - in this case I am using re-used produce bags, they float nicely on the flat and eventually, the plants.
They will go on top of the propane heater where the pilot's rising heat will keep the flat warm. Tomatoes like to germinate around 75 degrees so this works great. I spot water them with the fine spray occasionally, usually around the edges. They'll be up in a few days, it's so fun to watch.