Heavens no. It's just barely safe for most crops. I'm in the Detroit area, so we have the same climate. It MAY be getting "iffy" for some of the cool weather crops like peas or lettuce, and onions planted now won't be as big as if planted in April, but even with the cool weather crops, it just depends on the season we have. Many years, it's not all that hot and they do fine into the summer. Realistically, you can plant cool season crops from late March/early April until about the first of June, and then do a fall planting from mid July through mid August (depending upon the crop and days to maturity). With warm season crops, from mid May through mid June, with a few things as late as early July (say, a really late crop of corn). Get out there and plant! Not a problem at all.

You have plenty of time. Both vegetables will be ok if you get light snows or frosts. I don't harvest my storage carrots until late October or early November. The cold ground makes them very sweet.

Very interesting reading. Thought I'd chime in on cherries now that spring is starting to arrive. I have a Black Gold cherry which appears to have now survived 2 winters. The buds were starting to swell this last weekend when I looked at it, same as the pie cherries. Sunday night the weekend before, the temp. reading overnight was 4. The year before last when I planted it, I finally realized I wasn't giving it enough water until Aug. and when I increased the water, it started to grow instead of having just the leaves that emerged in the spring with no growth. That fall, it didn't go dormant until cold temps in Nov. finally froze the leaves down. We only got down to about -20 that winter. I was worried last spring that it hadn't made it, and the new growth in Aug. didn't, but buds came out all over the stem and grew well last year (much more water all summer). In mid Sept. I stopped all water so it would dry down and the leaves turned colors and dropped in Mid. Oct. along with the pie cherries. This winter we got down to about -25, but we also didn't have warm spells like we have had so often the last few years. In fact, this spring it seems like spring still hasn't arrived. One nice day, then back to the 40's and 50's lately (75 today, supposed to be 50 tomorrow, maybe back close to 60 by next week). I get almost no natural rainfall, so controlling soil moisture is easy as long as I have a way water it. Also, the only protection it gets otherwise is a snow fence wrapped around it to try to discourage the deer.

I often start perennial and biannual seed in July. Right now I have shasta daisy, sweet william, foxgloves, painted daisy already germinated and am waiting on delphinium, columbine, salvia and sage to get started. I find it much easier to get them started outside when the soil is already warm and the temps make germination faster. If you start seed in July you can expect the plants to flower the following year. Some perennial and biannual seeds are very easy and some are hard. I follow directions on back of packet as far as if the seed needs to be covered or needs light and some need to be frozen for a while, set them on wet miracle grow potting mix, water well, but gently and put in a shady place until germination starts and then I move them to an area that gets a few hours of morning sun a day. Once their first set of true leaves is out I will move them into a place that gets 4 or 5 hours of morning sun. When their second set of leaves shows up the seedlings will be moved to either a nursery bed in my veg garden or for some into their permanent spot right away. The bulk will go to the veg garden and those I might cover with shade cloth if it is very hot (it will be in Arkansas in August). The hardest thing is to keep the soil moist while germination is going on and when they are vey small. Sometimes I have a complete failure, but for some like shasta, sweet william, foxgloves, painted daisy, gillardia they are so easy you will get dozens of plants. Almost always I get at least a few. Well worth the couple of bucks the packet of seed costs. Hope this helps.