What does "danger of frost has passed" mean?

Asked March 25, 2017, 9:29 PM EDT

Hello, I am planning on growing parsley, basil and bush green beans this year. I read on the UMD extension website that you should direct sow bush green beans outdoors when the "danger of frost has passed." I'm not too sure what that means (is that around April 1, April 15 or May 10?). I know for some vegetables like tomatoes and peppers, it's straight forward to not transplant anything until around Mother's Day. But I'm not too sure about green beans or parsley or basil that I will direct sow. The weather will be low 40s high 60s this coming week and I'm wondering if I could plant the parsley or bean seeds tomorrow or if that is too early. Could you clarify what "danger of frost has passed" means? Also, I've only done "indoor sowing" for tomatoes, peppers and eggplant. Is it "better" to do some indoor sowing for parsley, basil and lettuce and then transplant when the time is right or is it better to just sow outdoors? Thanks!

Howard County Maryland

2 Responses

The following page on our website should be of interest to you - SpringFrost/Freeze Dates. http://extension.umd.edu/growit/beyond-basics/spring-frostfreeze-dates-maryland
The last frost date in the spring and the first frost date in the fall dictate how long your growing season will be. You can take a gamble if you plant too early.
Frost dates are figured as a probability based on past history of frosts. As you will see in the chart, on the latest date listed, there is still a 1 year in 10, or 10% chance of a frost after this date.

In general, Mother's Day or later is a guide for planting warm season transplants and sowing seeds. The plants will not start to actively grow until the soil temperatures warm up. If you decide to plant, protect your plants from frost with a floating row cover, a lightweight gauzy fabric that also deters pests.

Parsley, basil, and beans are warm season crops and it is too early to plant outdoors. Wait until the last frost date has passed.
You can sow parsley and basil inside now or direct sow after frost is past.
You can sow leaf lettuce outdoors now in the early spring. It is a cool season crop. A floating row cover can promote good growth in the spring and deter pests. http://extension.umd.edu/growit/beyond-basics/floating-row-cover http://extension.umd.edu/growit/vegetable-profiles-lettuce

You can also sow lettuce indoors under lights.