Lilacs in First Leaf

I know it doesn't look like much but the first leaf of the lilac indicates that it is time to plant beets, cole crops (broccoli, kale, cabbage, turnips, etc.), lettuce, and spinach.  This is not just folklore but backed up phenology, the study of the timing of natural events.  Lilacs are most commonly used for observation and to time gardening activity.  I checked the soil temperature in my garden, it is 55-60 degrees.  That is well in the range for these crops.  

Here are some other indicators for planting: 

• Plant peas when forsythia blooms
• Plant potatoes when first dandelion blooms
• plant bean, cucumbers, squash when lilac is in full bloom
• plant tomatoes when lily-of-the-valley blooms
• plant eggplant, melons, peppers when iris blooms