Last Summer I spent quite a lot of time researching plant timing to figure out when to plant seeds in our greenhouse so they are all ready at the same time for our spring plant sale.I've seen the question a few times posed here about when to plant, when to have a plant sale, timing etc. I created a spreadsheet for myself to know when to plant, what. It was extremely helpful for me and I thought I'd share this for others. You just plug in your plant sale date and the spreadsheet counts back for you to tell you what date to plant your seeds. It also had PGR recommendations, note those amounts are for BNine. When researching the maturity time most manufacturers list a range, I shot in the middle with the range and it worked out well for me. You may have adjust based on your greenhouse and if you select ones that are early varieties. If you want to build upon it I suggest googling the plant with the variety name culture guide, you can usually find a pdf from the seed company with the information. I just stuck it all on a spread sheet to keep it handy. I hope this helps, also note I am by no means an Excel expert so this spreadsheet may not look the prettiest but it worked fine for me last year.