No, seeds starting mix is finer so that roots do not get torn up when you pull seedling apart when separating community flats/pots. It is mostly vermiculite peat moss and a bit of lime/dolomite to adjust pH. Potting mix is coarser and usually contains composted materials such as pine bark and other (originally) woody materials, often with a fluffer such as perlite or styrofoam, and lime/dolomite for pH adjustment. It can be used for starting seeds if you are not planning on pulling the plants out of the mix (I use it for starting everything). Potting soil is often much denser/heavier because it contains actual soil, I have seen it advertized for things that are to be permanently grown outside in containers like shrubs in planters, but someone else might have more info on this than me. Potting mix is usually better for most things than potting soil. For all of them you would have to check the bag to see if they contain starter fertilizer.

I don't know.. I don't know anything about Courtyard, but as you probably know, Midnight, Moonlight and Prosperity are in Galaxy and they are great cultivars. Here is the thing though, a 7 lb bag of Fenway costs $48 and a 10 lb bag of Galaxy costs $60. The Fenway is 50% filler so to equate to the same amount of seed in Galaxy, you would need 3 bags. I just did a full renovation last year and I also have a sprinkler system. If you willing to set it up to run 3x per day, 10 min per station for about a month, you don't have to worry about it drying out and don't need the Water Smart. That worked fine for me. You weren't planning on doing the renovation now are you? You would be much, much better off doing it in the fall and that would give you plenty of time to order from Rose Agri.

I do it because I get unusual plants/exotic colors only catalog seeds can give me. I do it because I like doing it. Yes, you can get earlier bloom with some plants. With others (like cosmos and zinnia) I find they do best planted directly outside. You learn from experience. Lately (after doing it for 30 years) it's become a bit of a chore so I stopped doing seeds that need to be started before March 1st and buy those plants in the nursery. I use an 8 tray light setup with two shop lights next to each other on each level, each light with one ordinary 40 watt tube and one full spectrum tube. Keep a list of when each plant needs to be started (by weeks before last frost), keep the lights no more than an inch from the plants, and always have a fan or slightly open window in the plant room to prevent fungus. Try to water from the bottom and without soaking the top of the soil. Have as much fun with this and go nuts obsessing over whatever you feel comfortable with. Rewmember, it's for pleasure!

DWD2, thank you for posting your methodology. It always good to see how others grow their seeds and compare methods. I have grown my own starts (36+ tomato varieties) for the past 5 years. Before last year, I had not had too many plant health problems, except for the first year when my light system was not close enough to my plants. In that year I had problems with leggyness. I strongly suspect that my problem last year was the seed starter mix, but it could have been a few other things. I may have introduced disease into the first batch by incorporating compost into the mix. I think this is unlikely because in other batches and other treys I did not use compost in the mix but still had the same problems. Also, once the plants were in the ground they recovered and grew well the rest of the summer. If it were a disease I would have expected that the plants would still have had problems after planting, which they did not. Tomatoes are really amazing in what they can take early on and still produce well. For example, I had a mouse eat all the leaves of two plants shortley after they were in the ground. There were only stems left and I thought they were done, but I did not pull them out. Both plants sprouted new leaves again and became bushy healthy plants. I was astounded. I have had others suggest that with an approximately 50/50 mix of vermiculite and peat, I may have had water retention problems that suffocated the roots. Thats possible, but I was pretty careful about my watering. I can't totally rule that out. It may also have been too many nutrients from a dilute solution of fertilizer at watering as the problems occured shortly after that. I have read that new seedlings don't need many nutrients becuase they get what they need from the seeds/cotyledons. Some have even suggested that you will cause more problems by fertilizing than just not fertilizing. The reason why I fertilized is because we had a number of storms in May that pushed my planting date back 3-4 weeks longer than our average frost date. So I fertilized a little. I may also have had root binding problems. There is another possiblity which DWD2 suggested. I used a seed heating matt for the first time last year and most of the tomatoes had it under them for at least a day. So I may have over-heated the soil a little and damaged the roots. However on the last seed trey that got started late, I did not use the heat matt because I suspected it may have caused the problems. Yet I still had the same problems in the last trey. My strongest suspicion is still the starter mix. I have read the ingredient list on several seed starting mixes. In most cases, they usually contain peat (as the main medium plus it has high cation exchange capacity) + vermiculite (for micro nutrient exchange and water retention) + lime (to balance the PH of the peat). They sometimes include perilite, but sometimes not (example Jiffy), they also sometimes include a few other things (mycorrhizae for example or a source of nutrients). The main ingredient that I was missing that most starter mixes have is lime for ph balance. I could not find lime in any stores in Utah at the time. They do sell it here, but it is not a common soil amendment in Utah because most Utah soils are slightly alkaline (PH 7.8-8.2). So most folks would not want to add lime. This year I am interested to try mixing my own starter again but I wanted actual recipies to get an idea of the right proportions to use. Also I had no idea that mycorrhizae was available so I am defintley going to use that in my mix. Alternatively I could just buy a pre-made starter mix, but I wanted to save money and its a learning experience as well.