When it Frosts in Early May
The perennial veggies, shrubs, and trees all survive a light or hard frost this time of year. However, fruit tree blossoms will die in a hard frost (28 degrees) and rhubarb and asparagus will go mushy and be inedible in a light frost, but the plants will not be injured. I learned last year to harvest these veggies all the day before a frost. However, they are both just coming up, so when the forecast said 32 for tonight, I tucked them both under a hay blanket. We'll see how they hold up in the morning.
The garlic can tolerate light frosts easily, which is good because it is so big and tall mulching it with hay could damage some of the tender leaves.
The only other things up in the garden are transplanted peas and onions from the fridge (you know how onions all want to grow this time of year - you can pot them up or plant them outside). A few tiny pea seedlings, wee spinach seedlings, and a few other seedlings just breaking soil (carrot, beet).
A couple of perennials are coming back in - most notably lady's mantle, lavender, thyme, oregano, poppies, daylily, tulip, lilac, and a feathery and dainty bleeding heart variety, but they should all do well.
My seedlings that have been getting stronger and healthier enjoying life in our small greenhouse have been brought back inside, as have all of my perennial potted plants from the fall. The aphids were really killing morale around here (mine) and the plants, but bringing them outside introduced natural predators, the ladybugs in my house FINALLY produced aphid eating larva, and my father-in-law told me about an aphid killing spray that actually works. The neem spray I used was so ineffective, I resorted to squishing, which was A LOT of work and very challenging when dealing with tiny sun starved seedlings (poor seedlings). The aphid killing recipe is: dish soap, oil, and water. I used olive oil and Dr. Bronner's but I think a proper detergent would work better. I put that in a spray bottle, shook it up a bunch and went to town. The oil is emulsified by the detergent. The oil coats their bodies and suffocates them. Or something like that. All I can say is it is VERY effective and my plants would have been a lot happier if I knew this in December when someone gave us a Trojan Horse.