Like the guy said above there really is no way to naturally get buds in mid-summer unless you grow a autoflowering strain and these strains are low yield and only medium potency at best.
Also, I see you say you are from PA and on 4/29 it looks like it will get very close to freezing overnight and will be cool the nights before and after that date. There is no rush to get them out, middle of May would be fine. It seems a little known fact around here on GC is the longer your plants are in vegetation the longer it will take them to produce buds, marijuana builds up a chemical(cant remember name, will look it up) that will delay flowering to begin. So if you start your plants early, they will get big but if frost comes early, you may be left with shit bud because it didnt have adequate time to finish. I know it sounds crazy but 2 plants of the same strain that have one started in March and one started in May, the one started in May will finish first.
Just something to think about.
Pay attention to your weather and other gardeners, when the gardeners start preparing their gardens for the season, you should be good. I know most people from my neck of Pennsylvania will not start their tomatoes until middle to late May.
Another way of knowing is get a probe thermometer and put in the ground and see what the ground temps are, 55 degrees and up is great for sowing seeds if you cant start them indoors. These digital thermometers can be expensive though, I had one given to me by a friend who is a Health Inspector, so Im not sure what they cost.
Good Luck with your grow my man!