Please see my two posts on March 30, 2014. Only the earliest of hybrids released had two parents,and both parents are known for some of them. Later hybrids can have up to 4 parental inputs in each breeding line,as I explained in a previous posts I mentioned above so 8 parental inputs in each line.The last one in each line is crossed with the last one in the other line to make the stable F1 hybrid. Yes,there are many companies that breed F1 hybrids,mostly in the Netherlands and Israel and Japan and China,some still in the US such as Petoseed,which does custom breeding for Burpee although Burpee now has some breeders back in PA but I don't know of any releases yet,and do so since commercial farmers want F1 hybrids and preferably determinate ones to facilitate machine harvesting and those in areas want ones with tolerance,no such thing as total resistance,where soilborne diseases are found,which is not in all places of the US.. Companies don't breed OP heirloom varieties, for that would be the antithises of the word heirloom and let us NOT get into a discussion of what an heirloom is or is not,I mean you can,but there are many threads here already about that,no one definition,and I'm out on that subject.,LOL. Heirloom tomato varieties are sourced from many places and most of them,well maybe some,end up being listed in the SSE Annual Yearbooks,where they are then available to SSEmembers. To date I've grown about 4,000 plus heirloom varieties and have in introduced close to 300 new ones from various sources myself. And if you look at Tania's superb data website she has individual pages for about 5,000 now and taking all the ones that are in seedbanks in different countries there are probably close to 20,000, I should live so long being 77 this June.LOL

jnjfarm I have not heard of Green Giant broccoli. Google search only brings up images of pre-packaged broccoli with the big green guy on the package. If you meant to say Green Goliath then I think the 76 DTM might be too long for the OP to start from seed now in Indiana to get a harvest before winter sets in. I agree with Wayne that an early variety like Pacman or Early Dividend would be a better choice for the OP at this point.

I say mix! When I bought for kitchen and bath I had 2 different sales reps tell me they liked Kohler best for bathroom and Delta best for kitchen. In the end I also liked the color choice in Delta for my kitchen faucet. Got Kohler for bath and I even mixed styles there. The style I liked best was very expensive so I got it on certain shower pieces where I didn't like the alternatives but went with a less expensive faucet and towel racks that match in color and compliment in style. In the end my bathroom has 3 different Kohler models/styles.. All the same color....I bet nobody even notices they're different.

Of course you can check! But don't be tempted to peek before twenty or more days. If you are using a heat mat to provide bottom heat, the seeds will germinate much more quickly. Verbena seeds can take forever to germinate, weeks and weeks. I've actually never seen a black plastic recommendation before. Usually, a covering of fluffy germination mix is all that is required for seeds that require darkness and that's all I've ever done as a professional or a retired hobbyist. I'd think that covering with black plastic would encourage mold and mildew and set the seedlings up for rampant damping off diseases after germination. Anyway, I'm not going to confuse you by telling you how I would do it, but just ease your mind about checking for germination. Be very careful that the medium is not overly moist when you cover it or your project will not be successful.