“In seed starting, which plant benefits the most by having a grow mat under it?” Question from Tim of Burton, Ohio
Answer: Some seeds need supplemental heat for germination, and these are almost always seeds for warm-season crops that naturally sprout when the outdoor temperatures heat up. Summer flowers, like cleome, cosmos, coreopsis, gomphrena, marigolds, salvias, and sunflowers, sprout better and grow faster with added heat. When it comes to herbs and vegetables, think of anything that thrives during the warmest times of the season–basil, corn, eggplant, okra, peppers, rosemary, and tomatoes all germinate and grow best with bottom heat.
“When is it safe to plant summer annuals? Should I wait until after Mother’s Day to plant my marigolds, petunias, and other annuals? I live in Central Ohio.” Question from Diane of Newark, Ohio
Answer: Always plant warm-season annuals, like petunias and marigolds, after the threat of frost has passed. To do this, you need to know your last frost date. The Old Farmer’s Almanac provides this data. Every gardener should know both their first and last frost dates for the growing season. Here is the data that is yielded when I search using your Zipcode: