|View from our porch: Tomatoes, Peppers, Basil, Beans covered with plastic sheets|
Common planting guideline suggests to start planting directly outdoors after Mother's day, but unfortunately that doesn't rule out occasional frost, even in May. So far this gardening year has been unusually cold, although if you remember last year we had an unexpectedly late frost as well and many farmers lost their vegetables. Fruit Orchards lost some of their seasonal peach produce due to the peach flower frost bite.
As a gardener you need to follow weather forecast, especially temperatures around 4am to 6am, when the temperatures are at their lowest. Tomatoes, beans, peppers are sensitive to cold as well as many flowers, herbs and fruit trees.
Cover Plants to Protect them from Frost Bite
For a short term frost protection you can use large plastic bins, glass jars to cover your plants or if you have a larger crop or long rows you can also use plastic cover. Plastic covers are cheap and can be purchased in a painting department at your local hardware store. Prop the sheets up so they are not touching the plants, they should be loosely fitting over the plants, use stakes to support the sheet up.
Next day, after the frosty night/morning has passed, lift the sheets and other coverings away from plants, you don't want your plants to "simmer", they can get easily overheated especially if it is sunny out.
Also remember if you have a plants in the containers, they are extremely susceptible to frost, their roots are unprotected. Make sure you protect these plants as well. You can take them inside, or to your garage, or cover them like I suggested.